archived-products-and-moulds

Hello everybody.. this is the very beginning of this new channel.

up the conversation around products and moulds!

Here I am! Maybe it isn't the best starting for the channel since my project isn't related on the "official" machines, but however ... I decided to follow my own path in developing the project. The main reason is that I love the marbling effect of the "hand mixed" molten plastic, so I made a small, and undoubtedly perfectible, compression molding system. I just started trying to make molds with the right shape and concept, I'm a lathe machinist and CNC programmer for two decades now, so I know how to machine metals and it helps me a lot, but I'm new to mold making , so any suggestion is more than well accepted. I made a system that allows me to heat and cool the molds with glycolate water (I'm working on it to improve it, at now I can reach no more than 50°C in the mold, but it is better than nothing) so, after a first try with a cold mold I made my first one with water passages. This one isn't machined on the CNC, but with my small benchtop milling machine, so it isn't perfect. I just finished a modification to reduce the thickness of the "burr trimmer ring" (I don't know if it is the right term, I know they call "tranciabave" here in Italy), where the molds comes in contact, to make easier for it to reduce the plastic burrs coming from the little excess material. This is the mold.

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6:40 PM

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6:42 PM

And this is the product (I removed the burrs on the lathe trying to have a good finish).

6:42 PM

6:43 PM

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Hi, I have an injection machine being built for me (due to be completed in May). I have my own cnc machine so will be making my own moulds. I know from experience from melting plastic in a toaster oven that it shrinks after it cools. I will be using HDPE in the injection machine. Does injected plastic also shrink after cooling and if it does, does anyone have any idea how much it shrinks? (edited)

Upcycler_Simon

Hi, I have an injection machine being built for me (due to be completed in May). I have my own cnc machine so will be making my own moulds. I know from experience from melting plastic in a toaster oven that it shrinks after it cools. I will be using HDPE in the injection machine. Does injected plastic also shrink after cooling and if it does, does anyone have any idea how much it shrinks? (edited)

Yes, it shrinks around 4%, depending on the starting temperature, from what I read on some molding information documentation. That is the main reason because you can't see plastic industrial products with thick walls, since while shrinking, it deforms the surface and even the shape of the object.

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Hi, we have just got our injection moulding machine set up and looking to source moulds, we aren't in a position yet to make our own but I'm really struggling to find anyone that can make them for us as the shot size is only 20g. Does anyone have any recommendations? I found a place in Leeds UK but they wanted to charge more than double what we'd paid for the injection moulder for one mould!

SamT411

Hi, we have just got our injection moulding machine set up and looking to source moulds, we aren't in a position yet to make our own but I'm really struggling to find anyone that can make them for us as the shot size is only 20g. Does anyone have any recommendations? I found a place in Leeds UK but they wanted to charge more than double what we'd paid for the injection moulder for one mould!

you could post it on #archived-talent-pool searching for a mould maker with some details about specific requirements, if you have a precise job/mould in mind you could instead #archived-post-jobs with your budget available (edited)

Mattia

you could post it on #archived-talent-pool searching for a mould maker with some details about specific requirements, if you have a precise job/mould in mind you could instead #archived-post-jobs with your budget available (edited)

perfect thank you I'll do that

SamT411

perfect thank you I'll do that

Have you tried searching the bazar? (edited)

Mattia

Have you tried searching the bazar? (edited)

yes and contacted everyone that says they'll post to us but no one so far is able to accomodate the small shot size.

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I think if you post exact requirements + budget + timeline in #archived-post-jobs someone will help you out

SamT411

Hi, we have just got our injection moulding machine set up and looking to source moulds, we aren't in a position yet to make our own but I'm really struggling to find anyone that can make them for us as the shot size is only 20g. Does anyone have any recommendations? I found a place in Leeds UK but they wanted to charge more than double what we'd paid for the injection moulder for one mould!

If you want, send me the drawing, if it isn't too complex maybe I can make it, on my mini mill or on the lathe at mi job, and however I can also ask to my employer if they can give you a quotation if it is needed to do it on a CNC miling machine. We aren't expert on molds, but...maybe it worth a try.

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Hi everyone! We are trying to make wall hangers from HDPE. However the base, that should lay flat against the wall curls up a bit after cooling (maybe because of mould shrinkage). I hope you are familiar with this issue, and can help me. ........... Because this is my first ever post in the Precious Plastic community, I would like to say a little about me. I was asked to help to manage a plastic workshop in Győr, Hungary. Our project is still in its infancy, but I hope we can work trough some problems and take steps forward. We have one injection machine and one shredder (which is weak, and has gaps between the teeth :(( ). If anyone is interested and would like to help me with a little mentoring, it would be much appreciated too. Have a great day :), Benedek!

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Bebe

Hi everyone! We are trying to make wall hangers from HDPE. However the base, that should lay flat against the wall curls up a bit after cooling (maybe because of mould shrinkage). I hope you are familiar with this issue, and can help me. ........... Because this is my first ever post in the Precious Plastic community, I would like to say a little about me. I was asked to help to manage a plastic workshop in Győr, Hungary. Our project is still in its infancy, but I hope we can work trough some problems and take steps forward. We have one injection machine and one shredder (which is weak, and has gaps between the teeth :(( ). If anyone is interested and would like to help me with a little mentoring, it would be much appreciated too. Have a great day :), Benedek!

The thing with HDPE is that it shrinks by 2 precent when heated and expands by 2 precent when cooled

Alex_recycles and creates

The thing with HDPE is that it shrinks by 2 precent when heated and expands by 2 precent when cooled

No, it is actually the opposite. When cooling it shrinks.

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Davide->PreciousPlasticRomagna

No, it is actually the opposite. When cooling it shrinks.

You sure about that ?

Yes, totally.

Davide->PreciousPlasticRomagna

No, it is actually the opposite. When cooling it shrinks.

Yes, it does shrink when it cools (When I open the mould I see the plastic piece being slightly smaller then the metal frame). And when it shrinks, the hanger part pulls the backplate into a curve. I'm going to try to take out the plastic from its form still warm, and clamp it to a flat surface. (Maybe what would work??)..... The other option is to redesign the mould, but I don't know anything about 3d designing. So please, if anyone has any ideas, or experience with this, give me a text or an email to komczbenedek@gmail.com. I was invited into this project because it was stagnating. I really want to make progress. But first I need help.

Maybe try to cool down the mould completely before opening, that's what i do. Still, HDPE is the worst plastic concerning shrink and warp. Just try with PP or PS to see if this changes the game.

Bebe

Hi everyone! We are trying to make wall hangers from HDPE. However the base, that should lay flat against the wall curls up a bit after cooling (maybe because of mould shrinkage). I hope you are familiar with this issue, and can help me. ........... Because this is my first ever post in the Precious Plastic community, I would like to say a little about me. I was asked to help to manage a plastic workshop in Győr, Hungary. Our project is still in its infancy, but I hope we can work trough some problems and take steps forward. We have one injection machine and one shredder (which is weak, and has gaps between the teeth :(( ). If anyone is interested and would like to help me with a little mentoring, it would be much appreciated too. Have a great day :), Benedek!

hi! i cant open the pictures, i dont know why, would you mind sending a screenshot to understand how it looks like?

1:13 PM

if its warping or you have heat sinks that means you need to hold the pressure for longer after injecting so that it cools down under pressure

Hi all, I posted this in the machines thread but I'm posting it here too JIC. How big of an object can the injection machines make? I have an object that I think is on the large end for these machines. Each object is about 70-80g (PET), Vol: 60x80x55 Is it too big? A related question I had was about the pressure/force required to make the object, and if the machine+me could produce that force (edited)

Carolina

hi! i cant open the pictures, i dont know why, would you mind sending a screenshot to understand how it looks like?

Hi! Can we connect trough email? I could send you some photos there. Also I'm not always active here. My adress is komczbenedek@gmail.com

I have a plank extrusion question that was brought up. Why do we start beam extrusions from one end to the other instead of extruding directly into the center for beam making? All i can figure is for space reasons, but if you consider it, the extrusion machine only has to extrude half as far so there's a potential for there being less resistance to the plastic flow when filling a beam mould. Any thoughts on this? I plan on giving it a try when i find the time to figure out a 90 degree fitting for my extrusion machine to beam mould

Bebe

Hi! Can we connect trough email? I could send you some photos there. Also I'm not always active here. My adress is komczbenedek@gmail.com

we prefer to keep the conversations here so everyone can learn from everyone's questions

(edited)

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Hi everyone, just one short question.... we produced a good quantity of tiles in HDPE and we wanted to realize the twister game with it, which means using them as outdoor pavers. But we are concerned about the direct exposure to sun... are there any against indications for that?? Thank you!

xeroblaze

Hi all, I posted this in the machines thread but I'm posting it here too JIC. How big of an object can the injection machines make? I have an object that I think is on the large end for these machines. Each object is about 70-80g (PET), Vol: 60x80x55 Is it too big? A related question I had was about the pressure/force required to make the object, and if the machine+me could produce that force (edited)

I'm working on a machine that should be ready in the next few weeks, it has a massive ~350gm capacity

So it's all dependant on the machine you're working with

Ben - Precious Plastic Ciledug

I have a plank extrusion question that was brought up. Why do we start beam extrusions from one end to the other instead of extruding directly into the center for beam making? All i can figure is for space reasons, but if you consider it, the extrusion machine only has to extrude half as far so there's a potential for there being less resistance to the plastic flow when filling a beam mould. Any thoughts on this? I plan on giving it a try when i find the time to figure out a 90 degree fitting for my extrusion machine to beam mould

I'm guessing Beam extrusion starts at the end so you can make it as long as you want.

Hello. I have a question. If my organization was to collect, clean, shred, and sort HDPE would we be able to send it to someone who could use it to make lacrosse heads?

Lacrosse heads look like something that an injection mold could do. But you'll have to find someone who can model and create the mold for you. (Might be wrong though).

Ben - Precious Plastic Ciledug

I have a plank extrusion question that was brought up. Why do we start beam extrusions from one end to the other instead of extruding directly into the center for beam making? All i can figure is for space reasons, but if you consider it, the extrusion machine only has to extrude half as far so there's a potential for there being less resistance to the plastic flow when filling a beam mould. Any thoughts on this? I plan on giving it a try when i find the time to figure out a 90 degree fitting for my extrusion machine to beam mould

I haven't direct experience on extruding, but thinking about your idea it seems to me that your idea can cause some issue. The fastest the flow, the slow the cooling per lenght of the extruded part. Splitting in half the flow, you have double the cooling, the surface become worse, and if the cooling is uneven you risk to have a branch blocked by solidified plastic and one flowing.

Watching the kids play this year, those heads take a beating! would HDPE stand up to the pressure?

Davide->PreciousPlasticRomagna

I haven't direct experience on extruding, but thinking about your idea it seems to me that your idea can cause some issue. The fastest the flow, the slow the cooling per lenght of the extruded part. Splitting in half the flow, you have double the cooling, the surface become worse, and if the cooling is uneven you risk to have a branch blocked by solidified plastic and one flowing.

My extrusions tend to be 1.5 meters long, i always heat the mould so there's no flow issues like what you're describing. The extrusion surface comes out smooth.

NJ90210

Watching the kids play this year, those heads take a beating! would HDPE stand up to the pressure?

I’ve done some research and it seems like it would. At the very worst they would be great for making beginners equipment for kids just starting out. Then if they take to the sport they can invest in something a bit more sturdy

Our coach got lucky and sourced a bunch of STX 6000 for $20 apiece I think.

yeah i bought 25 sticks from a local used sporting goods store for like 125 bucks

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Ben - Precious Plastic Ciledug

My extrusions tend to be 1.5 meters long, i always heat the mould so there's no flow issues like what you're describing. The extrusion surface comes out smooth.

Never saw any extruded beam made with PP extruder coming out smooth, that's because I thought it isn't a good idea to split the flow in half. If your mold and extruder haven't flow limitations or issues, try to follow your idea!

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Davide->PreciousPlasticRomagna

Never saw any extruded beam made with PP extruder coming out smooth, that's because I thought it isn't a good idea to split the flow in half. If your mold and extruder haven't flow limitations or issues, try to follow your idea!

Well, let me introduce you to some thicc and smooth planks

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@Ben - Precious Plastic Ciledug that's a great texture. How do you heat your molds? Active contact with a cartridge heater, blown air, etc?

CitSciWorkshop

@Ben - Precious Plastic Ciledug that's a great texture. How do you heat your molds? Active contact with a cartridge heater, blown air, etc?

I need to shift to a contact style heater. Currently just a really long oven.

Hey, are the writings on the molds laser-made?

Which software should i learn to create my own 3d moulds? Which sort of files would i need to make?

Carolina

we prefer to keep the conversations here so everyone can learn from everyone's questions

(edited)

Alright then. I hope I can send the pictures here So again, we made the mould and basically it ate up all our budget. The form is a wall hanger, and it has a back piece which should be flat, but it curls up as the plastic cools.

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10:45 AM

Also, is here anyone that would help me with the Logo? I tried Figma, but I can't understand how it works, I'm sure it would be much faster is someone helped. I just need our name on the basic workspace logo, nothing fancy. P:S:: Why can't I send pictures that show in the chat?

Bebe

Also, is here anyone that would help me with the Logo? I tried Figma, but I can't understand how it works, I'm sure it would be much faster is someone helped. I just need our name on the basic workspace logo, nothing fancy. P:S:: Why can't I send pictures that show in the chat?

you are sending them in an strange format .HEIC ? that makes it not possible to preview in the chat and i still cannot open it, just open them on your computer and take a screenshot (edited)

Right. I did not realize that weird format.

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We want to extrude a beam as thin as possible. Is there anyone that has tried to extrude a beam of max. 1 cm thick (with a width of 3,5cm and 30cm long) The thinnest beam we have tried ourselves was 1,5cm by 3cm and the metal beam that served as mold was 2mm thick. Which showed us that the metal mold was too thin and the plastic got stuck and the builded up pressure which made the beam bent.

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Julie

We want to extrude a beam as thin as possible. Is there anyone that has tried to extrude a beam of max. 1 cm thick (with a width of 3,5cm and 30cm long) The thinnest beam we have tried ourselves was 1,5cm by 3cm and the metal beam that served as mold was 2mm thick. Which showed us that the metal mold was too thin and the plastic got stuck and the builded up pressure which made the beam bent.

Not extruded but compression molded. I'm working on that. To extrude a beam of that dimension you need to heat the mold well, or the flow become blocked by solidified plastic.

Julie

We want to extrude a beam as thin as possible. Is there anyone that has tried to extrude a beam of max. 1 cm thick (with a width of 3,5cm and 30cm long) The thinnest beam we have tried ourselves was 1,5cm by 3cm and the metal beam that served as mold was 2mm thick. Which showed us that the metal mold was too thin and the plastic got stuck and the builded up pressure which made the beam bent.

I think you will find that if you heat your mould hot enough, you won't have flow issues like this.

Hey! So I joined a Precious Plastic group. We have self made moulds, but they don't work so good. (They were professionally made with a CNC machine, but because they aren't symmetrical shapes, they bend and curl after cooling down). So I was thinking while we are experimenting with our own moulds, I should buy 1 or 2 that are working fine. So my questions to you: Is the Bazar the only place where I can buy good moulds? Is there any other place or group that sell them as well? Any tips before I go online and buy some moulds for our injection machine? Thanks for every response, Benedek!

I never checked, but aren't there any free mould designs available on the PP website?!

Bebe

Hey! So I joined a Precious Plastic group. We have self made moulds, but they don't work so good. (They were professionally made with a CNC machine, but because they aren't symmetrical shapes, they bend and curl after cooling down). So I was thinking while we are experimenting with our own moulds, I should buy 1 or 2 that are working fine. So my questions to you: Is the Bazar the only place where I can buy good moulds? Is there any other place or group that sell them as well? Any tips before I go online and buy some moulds for our injection machine? Thanks for every response, Benedek!

You can also check there : https://community.preciousplastic.com/how-to?tags=xEfoXujd49MgXTnMg7wj you will find some open mould design, and make it yourself or go to a local machining shop / laser cut. To buy moulds already done, yes, the bazar is the place to go !

@Ben - Precious Plastic Ciledug @Davide->PreciousPlasticRomagna thank you we will give it a try with pre-heating the mold and going for a thicker metal if there is anything available.

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Julie

@Ben - Precious Plastic Ciledug @Davide->PreciousPlasticRomagna thank you we will give it a try with pre-heating the mold and going for a thicker metal if there is anything available.

Making a rigid mould is a good way to avoid problems, but if the plastic and the mold are hot enough, you can have less problems. I don't know how your mold is made, however.

Julie

@Ben - Precious Plastic Ciledug @Davide->PreciousPlasticRomagna thank you we will give it a try with pre-heating the mold and going for a thicker metal if there is anything available.

I use 5mm steel plate. It doesn't seem to mind being cold and seeing lots of pressure but the plastic results get pretty bad on longer planks.

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1:46 AM

1:49 AM

These are extruded from the left side. They were both heated but top one was not heated enough. The further from the entry point of the plastic, the worse it gets when it's too cold.

plastic lumber can be nailed together like wood

however it appears that you will need to use concrete nails as regular nails may be too weak.

2:40 AM

without pre-drilling which kind of misses the point of building without a lot of extra tools and steps

Has anybody used PET instead of HDPE with the sheet press?

3:06 AM

Thaknjs

3:06 AM

thanks

TechDaddyTomerts

Has anybody used PET instead of HDPE with the sheet press?

just do not

3:07 AM

brittle, result, not good stuff.

hmmm. ok

3:09 AM

But Precious NEEDS to address the PET water absorption problem, it is one of the most wasted plastics (in form of water bottles) that are laying around.

3:09 AM

Without the use of PET all this plastic recycling is kinda useless.

TechDaddyTomerts

Without the use of PET all this plastic recycling is kinda useless.

We do not have the technical means to address this and PET is one of the most recycled plastics. Used PET where I live for example is now 52.8cents USD per kilo at the recycling centers. It is made into polyester fabric.

ok

3:41 AM

cool

3:42 AM

I would like to use PET as a building material

it is a high value plastic for recycling. We at PP are addressing the lower value plastics that are lesser recycled, Plastic films, bags, the PE and PP plastics

PET_Bricks_.pdf

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Butte (PP Philippines)

it is a high value plastic for recycling. We at PP are addressing the lower value plastics that are lesser recycled, Plastic films, bags, the PE and PP plastics

Ok, I understand

3:42 AM

thanks

PET is a terrible building material. When melted it is a milky brittle product that has very lot UV resistance

3:43 AM

very low UV

maybe PP is not the best orginization for what I want to do then?

3:43 AM

HDPE is NOT good for UV

3:43 AM

and it expands and shrinks a lot

3:44 AM

https://www.youtube.com/watch?v=-Nep7q5EpmE&ab_channel=TEDxTalks

TEDx Talks

3D Printing Houses with Recycled Plastic | Matt Watkins | TEDxTauranga

UV and expansion are unrelated qualities, and HDPE is used in outdoor furniture all the time. As a example the resovior in Los Angeles is filled with millions of HDPE plastic balls with a 50+ life because they have carbon added

ok, how do I add carbon?

You do not build structural HDPE buildings. You use it for the infill

3:45 AM

HDPE is not meant to be used for structural building support. simple engineering

3:46 AM

small sheds or furniture is OK,

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Well, I understand. But HDPE is NOT as common (where I am) as PET

HDPE and PP is the majority plastic used in food packaging

right

3:46 AM

I need To use PET

Where are you?

U.S. But doing work in Ghana, Africa

3:47 AM

in Ghana, there is TONS of plastic water bottles. and NO HOMEs

I am pretty sure that Africa has the same plastic as the Philippines where I am at

I would like to change that

3:47 AM

probably

3:47 AM

but there are very few recycling centers there

Plastic water bottles are terrible for building material. it was tried here for making eco bricks and it made even bigger mess after the plastic broke down

hmmm. ok

3:48 AM

that;s unfortanate

3:48 AM

did you look at the PDF I sent you?

you can make a alloy PET and HDPE but you will need to add in something for UV resistance like finely powdered charcoal or pigments

ok

i did not recieve a PDF

https://discord.com/channels/586676777334865928/968160764802269214/981372220356050964

3:49 AM

basiclly it says that PET plastic is BETTER than concrete

3:49 AM

for cinder blocks

3:50 AM

PET_Bricks_.pdf

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In theory,

thank you so much for your input

but in practice not really

yeah

3:50 AM

probably

3:51 AM

but in theory means "possibly"

you are talking something that is very difficult to make.

ya...

3:51 AM

but....

3:51 AM

if it actually worked

we are barely able to get a decent plastic board

3:51 AM

and been working on this for 4 years

3:52 AM

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3:52 AM

water issues in this batch

3:52 AM

because it is rainy season here

I see

3:52 AM

is that HDPe?

the plastic blocks require a BIG extrusion machine, bigger than the v4 to work right

oof

hdpe with some pp mixed in

wow

3:53 AM

ok

3:53 AM

why is it so hard?

3:53 AM

difficult*

we are extruding about 60 kilos of plastic daily

3:54 AM

many issues

wow

3:54 AM

have you tried "the brick"

water, dirt, coloring, surface finish,

yes we made the PP brick and sell the brick starter kit

ok, how much money can you make off of that?

the surface finish is very rough

Could you start a construction company?

3:55 AM

(sheds, etc)

we are selling the 2x4 foot beams for 25usd per 8 foot piece

3:56 AM

it is not used in buildings

that's a lot

3:56 AM

what is it used in?

furniture, and outdoor items

ok

we did try it in a door frame

how did it work

we also make eco pots

cool

it is a sellable product. people buy it so there is that

that's great

the key here is to keep it simple and keep it dumb, with a successful precious plastic procuct to start with

3:57 AM

you are learning a totally new trade

Yeah. I only have a PP shredder

3:57 AM

right now

3:57 AM

just got it

learn, make simple items, do not get too complicated

good advice

3:58 AM

thank

when you get better you can make more complicated items

3:58 AM

like this

3:58 AM

3:59 AM

this was 6 months to perfect the process

3:59 AM

full time

wowo

3:59 AM

what is it?

plastic soap container. the red block was our first attempt in 2018

4:00 AM

we went from this red block to the soap containers in 4 years

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WOW

4:00 AM

interesting

4:02 AM

I wish it was easier

and we went from working in my garage with only a few hand tools, to a full metal fabrication shop, laser cut parts, full time engineer, full time welder, in 4 years.

4:04 AM

all paid for by building machines, and molding plastic

4:04 AM

in the Philippines. just with hard work

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WOW

4:05 AM

That's amamzing

4:05 AM

I love it

if it was easy everyone would do it. Plastic fabrication is a trade, a skill to learn, just like learning how to work in wood, or metal, or sculpt clay

yes! I never would have thought that so many people would buy such "basic" plastic products

4:06 AM

that's so cool

just keep at it, experiment, all the information is somewhere on the internet for free

4:06 AM

but not all the free information is good

like you!

4:06 AM

Thanks!

Butte (PP Philippines)

but not all the free information is good

right

4:07 AM

What about creating a trackable re-usable water bottle with a builtin filter

4:07 AM

and make it kinda cheap

anyways i have to go offline. 10am here, I have to go to the metal fabricaiton shop to work

would people buy that?

Butte (PP Philippines)

anyways i have to go offline. 10am here, I have to go to the metal fabricaiton shop to work

ok sounds good!thanks!

water bottles are hard

yeah

keep it simple

ok!

4:07 AM

Yes!

plant pot, or something simple.

4:08 AM

chair

ok

trash can

with plastic baords?

yes

ok

4:08 AM

cool

trash cans are easy to make

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with HDPE?

3

4:09 AM

3

4:10 AM

chicken coops are another thing that is simple to make

1

good idea

dog houses

HDPE?

yes

ok

4:10 AM

go to work now

ok

blessings!

Butte (PP Philippines)

Click to see attachment 🖼️

That looks like it could be made into a Cider press pretty easily.

7:36 AM

Recycled plastic Cider press... I think that might do well in a hipster bespoke kinda way.

Butte (PP Philippines)

plastic lumber can be nailed together like wood

Very nice @butte !

Butte (PP Philippines)

Click to see attachment 🖼️

@Hugh I think we oughtta talk about this.. I think @butte was processing

loads of plastic into these beams.. maybe you two touch base and we write a story?

Butte (PP Philippines)

Click to see attachment 🖼️

These look great

do you have more pics?

Mattia

@Hugh I think we oughtta talk about this.. I think @butte was processing

loads of plastic into these beams.. maybe you two touch base and we write a story?

yes yes i agree - @Butte (PP Philippines) could you message me directly and lets work out a post for you

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Mattia

These look great

do you have more pics?

these were examples of items we were asked to make. we did not make the item in the pictures, but we will be fabricating a similar item.

Does anyone know where to potentially order a custom made Mould. I am currently in Thailand if that helps hahaha.

YBG90

Does anyone know where to potentially order a custom made Mould. I am currently in Thailand if that helps hahaha.

have you looked in the bazar?

https://bazar.preciousplastic.com/

I did but was unable to find someone that makes custom made moulds and is able to send them to Thailand or knows someone in Thailand that does so. But I will keep looking thanks for the suggestion though

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Happening now!

https://discord.com/events/586676777334865928/976234598897942538

so. we are trying to make a injection model however we arenot able to get a proper output from it. and the heaters that we have applied havent been able to heat the model as fast as it has in the extrusion.

7:46 AM

what maybe the problem?

7:47 AM

when we fed a mold through extrusion it tend to deform the mold from one side. what may have happened?

Anyone from the US Midwest?

I’m just wrapping up a mould for Purdue University in Indiana! @Joseph

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YBG90

I did but was unable to find someone that makes custom made moulds and is able to send them to Thailand or knows someone in Thailand that does so. But I will keep looking thanks for the suggestion though

we can ship to thailand from the Philippines. @Rory - Sustainable Design Studio can do the engineering work if you do not have the stl file or solid model. steel or aluminum molds

5:34 AM

should be low or no tax because in aesan

5:35 AM

plastic beam production coming along... we ran low on available plastic to keep production continous

Taylor

Anyone from the US Midwest?

I’m just wrapping up a mould for Purdue University in Indiana! @Joseph

I am in MN

2

7:44 PM

New mold to be tested. Made with cast iron, I want to test different heat transfer properties.

Taylor

Anyone from the US Midwest?

I’m just wrapping up a mould for Purdue University in Indiana! @Joseph

I’m from the East coast

Davide->PreciousPlasticRomagna

New mold to be tested. Made with cast iron, I want to test different heat transfer properties.

That’s awesome - I’ve never machined cast, how does it machine compared with aluminium?

speaker casing moulds - https://twitter.com/TechInsider/status/1537509590295887873?t=D513cULQCjERvIrAH_EfSA&s=19

Tech Insider (@TechInsider)

How nonrecyclable plastic is turned into speakers

Likes

147

3

I really like the imperfect texture extruded plastic can obtain, bumbs etc, I know it isn't ideal for commercial products but I like it. There is something very organic about the texture. Does anyone know a specific way of getting those textures everytime or exacerbating it? I'm almost slightly disappointed when the plastic comes out of the mold super smooth. Extrude slower at a lower temperature? Faster at a higher? Any insights are appreciated.

janitordebris

I really like the imperfect texture extruded plastic can obtain, bumbs etc, I know it isn't ideal for commercial products but I like it. There is something very organic about the texture. Does anyone know a specific way of getting those textures everytime or exacerbating it? I'm almost slightly disappointed when the plastic comes out of the mold super smooth. Extrude slower at a lower temperature? Faster at a higher? Any insights are appreciated.

This texture in an extruder mould, generally comes because the moulds is cold. So extrude in a cold mould (not used before, of completely cool down from previous extrusion). To exaggerate the process you can extrude as fast as you can at a low temperature (but of course with melted plastic). And to get things smooth, just do the opposite : warm (pre-heated) mould, lower speed, higher temperature.

FYI, when making plastic beams, I found that if the shredder is tearing the plastic rather than nice sharp sheared flakes, the plastic will feed about half the speed into the extrusion machine. I noticed this yesterday. Testing a new machine with some very nice shredded flake and it pumped out 15+ kilos in a hour. Then running some less than ideal flake i could not even get past 5 kilos per hour. it simply was not feeding well. Plastic flake size and quality matters.

2:58 AM

Also since we are doing so much large bottles now, we are looking at a variation of the Jeremy Fielding scary saw blade shredder to pre-shred big bottles into more manageable pieces before granulating.

Butte (PP Philippines)

FYI, when making plastic beams, I found that if the shredder is tearing the plastic rather than nice sharp sheared flakes, the plastic will feed about half the speed into the extrusion machine. I noticed this yesterday. Testing a new machine with some very nice shredded flake and it pumped out 15+ kilos in a hour. Then running some less than ideal flake i could not even get past 5 kilos per hour. it simply was not feeding well. Plastic flake size and quality matters.

Just as a note, i shredded something like 20kg of PP cups and i noticed that there's a difference between the shredded PP cups and shredded HDPE bottlecaps. The PP takes up almost 2x the space for the same weight when compared to the shredded HDPE bottlecaps. No doubt if everything was pellets things would flow much much smoother.

i am wondering if I should again try feeding the shred thru my pellet mill

update, so the plastic has been re-shredded after the blades in the granulator were sharpened and adjusted. It is looking like the plastic is just too dirty to extrude. Too much food residue in the plastic. I got some mesh, and made a sort of table to hold the mesh. Spray with bleach and the garden hose. Hopefully this will give a usable plastic as there is nearly 250 kilos of plastic in this batch of shred. We bought out every single bottle cap in the area, and have to use bottles now as feed stock.

Taylor

Anyone from the US Midwest?

I’m just wrapping up a mould for Purdue University in Indiana! @Joseph

Heya, how do u get the finish like that? Is it anodised?

Upcycler_Simon

Heya, how do u get the finish like that? Is it anodised?

Hey man! That finish is achieved by sandblasting, don’t go too hard or it will deform the ally, but a nice blasting removes tooling marks and makes a nice matte finish on the plastic parts

@Davide->PreciousPlasticRomagna Hi, I have a question about injection moulds. So I have an injection machine and cnc, and designing an aluminum mould to mill. I am having a hard time designing the nozzle part where the plastic will enter. I want to insert the nozzle like you did with your mould. How did you do it, just screw it in?

Doruk Yıldırım

@Davide->PreciousPlasticRomagna Hi, I have a question about injection moulds. So I have an injection machine and cnc, and designing an aluminum mould to mill. I am having a hard time designing the nozzle part where the plastic will enter. I want to insert the nozzle like you did with your mould. How did you do it, just screw it in?

This isn't an injection mold, I made it for compression molding. I put a "ball" (in reality it reminds more a small turd rather than a ball...) of molten plastic in the lower halve of the mold and then I press it. In this mold I think I can also insert a passage for injection molding, but since I haven't the injection machine (so far), I never thougt about how to do it.

1

Taylor

That’s awesome - I’ve never machined cast, how does it machine compared with aluminium?

It is something like the opposite of aluminum. Cast iron, expecially gray one like this, is hard and brittle, it is abrasive on the tools and it is something like impossible to polish. I tried because I had that raw material at home and I wanted to make a mold that can be precise and durable, I was asked to make >300 dominoes to play with them falling... The mold is very precise, it leaves virtually no burrs since there are 0.05mm between the two halves where the upper one goes in the lower one. Since the material is hard, I have no trouble about deformation under pressure.

Davide->PreciousPlasticRomagna

It is something like the opposite of aluminum. Cast iron, expecially gray one like this, is hard and brittle, it is abrasive on the tools and it is something like impossible to polish. I tried because I had that raw material at home and I wanted to make a mold that can be precise and durable, I was asked to make >300 dominoes to play with them falling... The mold is very precise, it leaves virtually no burrs since there are 0.05mm between the two halves where the upper one goes in the lower one. Since the material is hard, I have no trouble about deformation under pressure.

That’s awesome. Are you using dlc tungsten carbide? I have some cast aluminium ingots off my melted down chips from the cnc, and one day I’ll get around to trying those out. Making moulds from waste aluminium would really close the loop

Taylor

That’s awesome. Are you using dlc tungsten carbide? I have some cast aluminium ingots off my melted down chips from the cnc, and one day I’ll get around to trying those out. Making moulds from waste aluminium would really close the loop

No, I'm using Fraisa coated carbide tooling, I made this mold on the CNC lathe at job.

1

Davide->PreciousPlasticRomagna

Click to see attachment 🖼️

Tested. But the day after I had a little accident at job (nothing too bad, just a few stitches on two fingers) and I don't make photos of the result. In next days I post some pics!

Butte (PP Philippines)

update, so the plastic has been re-shredded after the blades in the granulator were sharpened and adjusted. It is looking like the plastic is just too dirty to extrude. Too much food residue in the plastic. I got some mesh, and made a sort of table to hold the mesh. Spray with bleach and the garden hose. Hopefully this will give a usable plastic as there is nearly 250 kilos of plastic in this batch of shred. We bought out every single bottle cap in the area, and have to use bottles now as feed stock.

Well plastic is washed, and re-shredded. But still slow to extrude. the jagged edges from the first shredding, are causing the material to feed slow. my employee ran the machine almost a full 200 kilos without checking the blade sharpness or adjustment. I am wondering if I can briefly heat the shred flake with a torch and cause the rough edges of the flake to melt and make it more of a pellet consistency?

3:30 AM

Also I have been thinking about the plastic brick project. Do we really NEED to make the brick interlocking with plastic? Why could we not just use cheap steel rod to pin the pieces together? Considering that we already need to use thread rod to tie the existing brick design together? We could easily make a drilling jig for the holes and this job could be done in the field with hand tools, and a miter saw?

Butte (PP Philippines)

Also I have been thinking about the plastic brick project. Do we really NEED to make the brick interlocking with plastic? Why could we not just use cheap steel rod to pin the pieces together? Considering that we already need to use thread rod to tie the existing brick design together? We could easily make a drilling jig for the holes and this job could be done in the field with hand tools, and a miter saw?

I would say not necessarily, I think the main thinking there is : the bricks needs to be hollow or they contain too much plastic (high cost), so the mould is complex already and adding an interlocking system doesn’t make it much more complex. But if the material cost is reduced (like adding sand, ashes, wood the the plastic), then why not

Yann

I would say not necessarily, I think the main thinking there is : the bricks needs to be hollow or they contain too much plastic (high cost), so the mould is complex already and adding an interlocking system doesn’t make it much more complex. But if the material cost is reduced (like adding sand, ashes, wood the the plastic), then why not

As someone who has already made a bunch of the PP bricks, the labor involved to de-mold and reassemble the mold again is extremely labor intensive. Even at the low third world labor costs of the Philippines, it simply is not feasble. Whereas plastic some types the local gov units are paying money for it to be taken away.

4

1

12:00 PM

Red one is PP, green one is LDPE

12:01 PM

4

1

12:02 PM

Since LDPE gives me the best result (abd and I know it flows a lot better in the mold), seems I definitely make the water passages in the mold to heat it.

Question

‍♀️ My project idea is to make recycled plastic chain links like these: https://www.etsy.com/listing/784837823/50-pcs-assorted-color-flat-twist-plastic?click_key=6550acf590859d78373a5022b730ab68ea6d4a1e%3A784837823&click_sum=f46139e8&rec_type=ss&ref=landingpage_similar_listing_top-8&frs=1 (couldn't find any recycled options on the market) and make croakies/face mask lanyards

50 Pcs Assorted Color Flat Twist Plastic Chain Links Open - Etsy

This Chain Links item by DIYartworld has 112 favorites from Etsy shoppers. Ships from China. Listed on Jun 9, 2022

1:17 AM

I was told by a local precious plastic person in my area that they didn’t think that this idea would work for recycled plastics. What do you guys think?

I wanna turn these chains into crookies and facemask lanyards

the end product for all the plastic lumber we been making.. Sand boxes. they hold sand for golfers to refill their bottles of sand. that sand is used to fix divots on the greens. since the tropical climate here is so harsh to metal and termites attack wood, the course was looking for a better item.

8

3

Please share when in location

Does anyone have experience building Injection molds for GEODESIC DOME 5-way + 6-way joints? I would like to make a mold like this in Brazil, but I find it difficult

9:16 PM

https://bazar.preciousplastic.com/moulds/injection-moulds/injection-mould-for-geodesic-dome-5-way-6-way-joints/

Moulds :: Injection Moulds :: 2 Injection moulds for GEODESIC DOME ...

geodesic dome joints injection mould how to plastic recycling design plastmakers

9:16 PM

I wanted this mold, but they don't ship to Brazil, any suggestions?

Precious Plastic Espírito Santo

https://bazar.preciousplastic.com/moulds/injection-moulds/injection-mould-for-geodesic-dome-5-way-6-way-joints/

have you thought about just buying the machining file and having a local cnc shop make it? That is how I do it now.

thank u so much

5

4:32 AM

leopold bench is perfect for the PP lumber

4:33 AM

a friend made this from wood, but it can be easily done in PP lumber

3

Butte (PP Philippines)

a friend made this from wood, but it can be easily done in PP lumber

Thanks for sharing the design. This saves so much time and brainpower. Since i need a bench and have planks....i'll give this a try.

2

Hi everyone i wanted to ask your opinion about this product, its a bowl made of recycled plastic bottle caps, im working on making some products like plates or glass out of it but im worried about the material, is it toxic for the food? should i write some warnings about it if i try to sell it? maybe the design is not that good? im doing this in a resin mold and melting the plastic in a wood oven, maybe should i use another method? this is my first time trying this so please tell me any comment or critic about it, it will help me a lot

Hanekáwa

Hi everyone i wanted to ask your opinion about this product, its a bowl made of recycled plastic bottle caps, im working on making some products like plates or glass out of it but im worried about the material, is it toxic for the food? should i write some warnings about it if i try to sell it? maybe the design is not that good? im doing this in a resin mold and melting the plastic in a wood oven, maybe should i use another method? this is my first time trying this so please tell me any comment or critic about it, it will help me a lot

Different countries have different regulations and classifications for recycled food grade plastic. Some countries do not allow for recycled plastics to be labeled as food grade. So i'd say it depends on your country and depends on lab testing if required. Also depends on how you clean your plastic and if there's any sort of crevices in the plastic. It's MUCH easier to just assume that nothing we make is food grade and tell customers this.

Hello! [Looking for someone who can design our plastic injection mould] We are a small company based out of Sweden looking to get started with plastic injection molding. Our machine is currently in the process of being built and now it is time to start creating the molds as well. We sell rings made out of recycled plastic, which we previously made on the lathe which took ages. There is a company who can manufacture the mould for us with proper machinery but we need someone with expertise in mould design to help us create it (in some kind of 3D program). We have the ring created already in a 3D program but need to make it into a mould. We are also willing to pay for this. Kind Regards, Adam

M0lnet

Hello! [Looking for someone who can design our plastic injection mould] We are a small company based out of Sweden looking to get started with plastic injection molding. Our machine is currently in the process of being built and now it is time to start creating the molds as well. We sell rings made out of recycled plastic, which we previously made on the lathe which took ages. There is a company who can manufacture the mould for us with proper machinery but we need someone with expertise in mould design to help us create it (in some kind of 3D program). We have the ring created already in a 3D program but need to make it into a mould. We are also willing to pay for this. Kind Regards, Adam

I know someone who could probably help you there. I can send you his mail address

DataWorm (PP Berlin)

I know someone who could probably help you there. I can send you his mail address

Thank you!

1

Fritz @easymoulds does great moulds!

2

Having a BIG problem sourcing plastic to recycle these last couple weeks. Am I the only one?

M0lnet

Hello! [Looking for someone who can design our plastic injection mould] We are a small company based out of Sweden looking to get started with plastic injection molding. Our machine is currently in the process of being built and now it is time to start creating the molds as well. We sell rings made out of recycled plastic, which we previously made on the lathe which took ages. There is a company who can manufacture the mould for us with proper machinery but we need someone with expertise in mould design to help us create it (in some kind of 3D program). We have the ring created already in a 3D program but need to make it into a mould. We are also willing to pay for this. Kind Regards, Adam

@Rory - Sustainable Design Studio attention (edited)

Butte (PP Philippines)

Having a BIG problem sourcing plastic to recycle these last couple weeks. Am I the only one?

that would be great news

1

Butte (PP Philippines)

Having a BIG problem sourcing plastic to recycle these last couple weeks. Am I the only one?

No problem in Indonesia. Recycling networks here are wide and vast on the big islands.

Hello everyone I am looking to develop a product. I am interested in 100% recycled. I think I have to produce 5000 units per month. The product consists of Polycarbonate 5000U/month Polyethylene 5000U/month Each product is about the size of a fist thank you for your answers

Answers? Where is the question?! xD

vincent0420

Hello everyone I am looking to develop a product. I am interested in 100% recycled. I think I have to produce 5000 units per month. The product consists of Polycarbonate 5000U/month Polyethylene 5000U/month Each product is about the size of a fist thank you for your answers

What's your question?

Excuse me Can anyone produce this? That is the question

vincent0420

Excuse me Can anyone produce this? That is the question

This is a global community and there's workspaces all over, but not everyone is on Discord. Where are you located? What type of item do you want to produce? Do you know what machine is required for the production of your product?

I live in Marseille in France I develop a navigation light for boats The base will be black and the caps will be transparent I think we need an extruder

Maybe more a case for an injection machine? How many gramms are your models?

What are people using for mould release agents and has anyone used anything organic?

vincent0420

I live in Marseille in France I develop a navigation light for boats The base will be black and the caps will be transparent I think we need an extruder

i see two precious plastic workspaces in Marseille

4:37 AM

https://www.instagram.com/ateliermelt/

Login • Instagram

Welcome back to Instagram. Sign in to check out what your friends, family & interests have been capturing & sharing around the world.

4:37 AM

https://www.instagram.com/les_petits_labos/

Login • Instagram

Welcome back to Instagram. Sign in to check out what your friends, family & interests have been capturing & sharing around the world.

vincent0420

I live in Marseille in France I develop a navigation light for boats The base will be black and the caps will be transparent I think we need an extruder

Please have a look at the community map. Not everyone is on discord or the map, but the map is a good start. https://community.preciousplastic.com/map

Precious Plastic Community

A series of tools for the Precious Plastic community to collaborate around the world. Connect, share and meet each other to tackle plastic waste.

Ben - Precious Plastic Ciledug

Please have a look at the community map. Not everyone is on discord or the map, but the map is a good start. https://community.preciousplastic.com/map

Thank you

InspiredMechanic

What are people using for mould release agents and has anyone used anything organic?

Silicon oil is what we found working the best. But you can also try vegetal oil that have a high burning temperature, we tried peanut oil and grape seed oil with good results.

InspiredMechanic

What are people using for mould release agents and has anyone used anything organic?

I've tried palm oil but it tends to discolor the plastic. I've met someone who uses lotion as a release agent which is a bit different. Sticking to silicone mould release agent has great results.

Yann

Silicon oil is what we found working the best. But you can also try vegetal oil that have a high burning temperature, we tried peanut oil and grape seed oil with good results.

Thank you @Yann and @Ben - Precious Plastic Ciledug ! I have some sesame oil but it's a bit pricy so I will try peanut oil and grape seed.

InspiredMechanic

Thank you @Yann and @Ben - Precious Plastic Ciledug ! I have some sesame oil but it's a bit pricy so I will try peanut oil and grape seed.

You need something with a high smoke point, otherwise you're gonna have issues with bubbles and likely more discoloration. Here's a list i found online. *palm oil is 450F-232C, it's probably the cheapest available stuff in indonesia, but i cant speak for other countries (i think europe banned imports?)

Ben - Precious Plastic Ciledug

You need something with a high smoke point, otherwise you're gonna have issues with bubbles and likely more discoloration. Here's a list i found online. *palm oil is 450F-232C, it's probably the cheapest available stuff in indonesia, but i cant speak for other countries (i think europe banned imports?)

Wow! Olive oil is a lot higher than I thought and California has lots of it! But I can't have olive oil around without a baguette! (edited)

8:46 AM

And some balsamic vinegar.

8:48 AM

Thank you this is really helpful!! I will try it this week. I need to reflow 3 clocks that I didn't compress long enough so they warped.

hi people this is my first post/question here. We are a group of students from Augsburg University and are trying to establish a Precious Plastic workspace at the university since 2 semesters. Currently we have a project where we want to make a bottle opener. Our idea is as you can see on the picture a bottle opener with a coin. Now my question: Does anyone have experience with injection molds that create cavities in the part? We need a slider that goes in and out. What is the easiest/best way to implement something like this ? Maybe there is someone here who has a similar problem. many thanks and greetings from Augsburg(Germany)

Prototyp_Bottle_opener.pdf

129.29 KB

@(Christoph) fruitdudeI think this is a case for overmolding:

12:34 PM

https://www.youtube.com/watch?v=yEomyn1oTTc&ab_channel=TheTOOLSShow

The TOOLS Show

Overmolding Handles

1

(Christoph) fruitdude

hi people this is my first post/question here. We are a group of students from Augsburg University and are trying to establish a Precious Plastic workspace at the university since 2 semesters. Currently we have a project where we want to make a bottle opener. Our idea is as you can see on the picture a bottle opener with a coin. Now my question: Does anyone have experience with injection molds that create cavities in the part? We need a slider that goes in and out. What is the easiest/best way to implement something like this ? Maybe there is someone here who has a similar problem. many thanks and greetings from Augsburg(Germany)

Hey! Seems trycky to get a cavity there. Though might be easier to have a place in the mould in where you place the coin so that it get injected around it. Look at this commuinty examples

https://bazar.preciousplastic.com/products/household/bottle-opener-pp/ (edited)

Recyceld Bottle Opener

Bottle opener made from recyceld polypropylene and a Swiss 10 cent piece. Available in different Colours and mixtures. Personalization available by showing year the coin was made. Contact us for special wish

2

3:07 PM

https://bazar.preciousplastic.com/products/household/bottle-opener-key-ring/

Products :: Household Items :: Bottle opener - key ring

can anyone help me

6:59 PM

with designing a mold

@Alex_recycles and creates Whats your question or problem?

FYI, something not covered in the about plastic pages is that there are multiple types of HDPE. We are learning this the hard way as we start to make plastic lumber on a larger scale. there is a injection mold grade and blow mold grade. Generally the Blow mold HDPE is in blow mold HDEP bottles, and the injection grade is in the caps and similar. Blow mold HDPE is EXTREMELY difficult if not impossible to injection mold. It is also much more difficult to extrude. We ran 100 kilos of HDPE recycled pellets yesterday that was blow mold grade. It did not fill the molds as easily as the other plastic. We resorted to thinning it down with PP flake to make it fill the mold. Today we will be trying different percentages of HDPE/PP alloy for our lumber. starting with a 25% HDPE. Mainly because PP is now half the cost of HDPE over here as we do not have a street collection system and rely on junk shops and other collectors for our raw product.

1

Butte (PP Philippines)

FYI, something not covered in the about plastic pages is that there are multiple types of HDPE. We are learning this the hard way as we start to make plastic lumber on a larger scale. there is a injection mold grade and blow mold grade. Generally the Blow mold HDPE is in blow mold HDEP bottles, and the injection grade is in the caps and similar. Blow mold HDPE is EXTREMELY difficult if not impossible to injection mold. It is also much more difficult to extrude. We ran 100 kilos of HDPE recycled pellets yesterday that was blow mold grade. It did not fill the molds as easily as the other plastic. We resorted to thinning it down with PP flake to make it fill the mold. Today we will be trying different percentages of HDPE/PP alloy for our lumber. starting with a 25% HDPE. Mainly because PP is now half the cost of HDPE over here as we do not have a street collection system and rely on junk shops and other collectors for our raw product.

It depends on the additives. There are also several kind of PP, some are for injection, some for blow molding and some for vacuum forming. Even the temperature in wich they are designed to work means a lot. For example, speaking about injection one, I found a lot of difference between the hand/body cream container I find here (precisely, Nivea Soft creme container) and the ice cream cups made for the "coppa del nonno" (grandpa cup, it is a cooffee ice cream) here in Italy. The first one is brittle and it is easy to shred and it tend to melt (in oven, for compression molding) without being too sticky, the cup is the opposite, a lot flexible and soft and it tend to become a sticky puddle in the oven. It is a matter of research the right procedure...

We are starting to get more tech assistance from companies in the plastic industry lately. There is a lot we did not know before. For example de-gas the extrusion machine, we really need a method for the v4 machine to do this. We are finding big issues with moisture causing back pressure and preventing the machine from feeding the plastic. We are also working on getting some donations of older plastic molding and extrusion machines from some local plastic manufacturers. equipment that is a bit worn and not suitable for big production, but too valuable just to send for scrap.

We had a group meeting with fellow plastic recycling manufacturers on Tuesday this week. A lot of good information was shared. One issue not really mentioned in the PP universe is materials handling. How do we handle the large amounts of shred plastic we process as we get into the hundred+ kilos per day production. We had a big dust collector, but it was used on another project. So now we are looking at a more industrial blower, and 55 gallon metal barrels to store and keep our shred. We are not at the point where we need a storage tank (yet) but one of the local industry startups has passed that point, and they are having a hard time managing the micro plastic and stray bits of plastic flake on the floor. The current idea locally at least is to use grain handling blowers (although wood workshop dust collector will also do the same task) The local industry partner is running 50hp granulators, but running into issues with heating of the plastic. We are also running into these similar issues with the smaller 5hp granulator.

2:19 AM

In addition, we think that a 2 stage plastic shredding system needs to be devised. A 2 shaft shredder to process the big stuff into more manageable flake. This flake can be easily washed, and then run thru a granulator at the second stage. Big pieces are more efficient with a 2 shaft shredder, but the final 6mm flake size needs to be handled with a high speed granulator, that can not handle big pieces efficiently but can process the small flake size fast.

does anyone sell motors for shreaders ?

Alex_recycles and creates

does anyone sell motors for shreaders ?

Where are you located?

https://www.youtube.com/watch?v=T0-Fp18B0O4

Action BOX

We Made Our Own Building Blocks At Home

Ben - Precious Plastic Ciledug

Where are you located?

USA

5:31 AM

NY

Alex_recycles and creates

USA

If you were in Indonesia I know where to go. Amazon has quite a few electric motors available that would work, but I suggest contacting a workspace in the USA and ask them where they sourced their motor from.

what metal do you recommend for molds stainless steel or aluminum ?

Alex_recycles and creates

what metal do you recommend for molds stainless steel or aluminum ?

From my 20+ years of machining experience... Stainless steel can be used but it is a very problematic alloy to machine. It also tend to warp with temperature change. It also haven't a big strenght. I don't recommend it, it is an alloy made to resist corrosion. In the industrial molding world they use tempered steel like K100 or 1.2311, but they made mold that need to last years of continue cycle. For our need I think aluminum molds (made from Anticorodal, like 6082 alloy, or ergal, like 7075 alloy) are more than enough, expecially for injection molding. I'm experiencing with other materials for my compression molds, since I have to make a tight fit between the two halves it is better to have a hard surface at least on the coupling/"sliding" zones. I made a mold with cast iron, it is good but it isn't the right material to have thin parts on the mold, since it is fragile. For the next ones I'm thinking about using case hardening steel like 18NiCrMo5, it has to be case hardened and tempered to have a hard surface on those zones. For injection molding for small scale production any mild steel can be ok, since we are speaking about injecting in a static mold. Steel can be better than aluminum since it has less thermal conductivity, then the plastic remains hot for more time during injection. I think for thin plastic parts it can be better.

I was wondering about compression molds

Alex_recycles and creates

I was wondering about compression molds

I'm working on that. At the moment I'm making molds with precise sliding surfaces and two guide pins to align the two halves precisely (~0.02mm play) and some channels to let the excess plastic flowing out. The press doesn't press the two halves together, but the stroke is stopped directly by the plastic when the upper halve has closed the channels and there isn't way for it to escape, closing the channels, in this way I can continue pressing the plastic until it solidifies, to make the part straight. Take a look on the cast iron ones I posted some weeks ago.

the simplest plastic beam chair and bench. Leopold bench

4:19 AM

About Aldo Leopold Plans to build your own Leopold bench for birdwatching and nature photography | Iowa DNR-Aldo Leopold was born in Burlington in 1887. As a boy with a lively interest in studying birds and natural history, he spent hours observing nature and exploring the river bluffs. A top high school student, he studied forestry at Yale University, which offered the nation’s first graduate forestry program. Earning a master’s degree in 1909, he joined the U.S. Forest Service, still in its infancy, established in 1905 under ardent conservationist, President Theodore Roosevelt. After just a few years, Leopold became supervisor of the 1.5 million-acre Carson National Forest in New Mexico (which was still a territory). Here, he developed the first comprehensive management plan for the Grand Canyon and wrote the Forest Service’s first game and fish handbook. He also proposed the first national wilderness area in the Forest Service system, the Gila Wilderness Area in New Mexico. He later taught at the University of Wisconsin and was at the forefront of wildlife conservation and management. The internationally recognized scientist and gifted writer penned the non-technical classic, A Sand County Almanac in 1949, regarded as one of the century’s foremost books of the conservation and environmental movement. Using short stories, he examined humanity’s relationship to the natural world. Unfortunately, just one week after hearing it was to be published, Leopold died of a heart attack on April 21, 1948 while fighting a wildfire. With more than 2 million copies sold, it has become one of the most respected books about the environment ever published, and Leopold is regarded by many as the most influential conservation thinker of the 20th century. Learn more at The Leopold Foundation at aldoleopold.org and his hometown group, leopoldheritage.org (edited)

2

Butte (PP Philippines)

FYI, something not covered in the about plastic pages is that there are multiple types of HDPE. We are learning this the hard way as we start to make plastic lumber on a larger scale. there is a injection mold grade and blow mold grade. Generally the Blow mold HDPE is in blow mold HDEP bottles, and the injection grade is in the caps and similar. Blow mold HDPE is EXTREMELY difficult if not impossible to injection mold. It is also much more difficult to extrude. We ran 100 kilos of HDPE recycled pellets yesterday that was blow mold grade. It did not fill the molds as easily as the other plastic. We resorted to thinning it down with PP flake to make it fill the mold. Today we will be trying different percentages of HDPE/PP alloy for our lumber. starting with a 25% HDPE. Mainly because PP is now half the cost of HDPE over here as we do not have a street collection system and rely on junk shops and other collectors for our raw product.

It seems to me that making a plastic alloy is a bad idea for future recycleability. You can probably never seperate them again

Butte (PP Philippines)

We are starting to get more tech assistance from companies in the plastic industry lately. There is a lot we did not know before. For example de-gas the extrusion machine, we really need a method for the v4 machine to do this. We are finding big issues with moisture causing back pressure and preventing the machine from feeding the plastic. We are also working on getting some donations of older plastic molding and extrusion machines from some local plastic manufacturers. equipment that is a bit worn and not suitable for big production, but too valuable just to send for scrap.

Sounds very good!

Paul Bogaers

It seems to me that making a plastic alloy is a bad idea for future recycleability. You can probably never seperate them again

they are already combined so you can choose to throw them away now or find something to use them for. With 2 of the worlds top ocean plastic sources located within 10km of where I sit right now, I think that mixing the sachet plastic is the least of our worry.

Can’t afford to buy moulds or machines to melt metal but I’m experimenting with making silicone moulds

Paul Bogaers

It seems to me that making a plastic alloy is a bad idea for future recycleability. You can probably never seperate them again

That makes sense, but you have to remember that the major % of collected plastic is going to become fuel for incinerators. And, from what I know, at least here in Italy, they recycle only packaging, not other objects. For example toys, kitchen machinery parts and so on aren't recycled. Maybe it isn't a major problem mixing plastic to make durable objects, rather than let them to be burned.

Butte (PP Philippines)

they are already combined so you can choose to throw them away now or find something to use them for. With 2 of the worlds top ocean plastic sources located within 10km of where I sit right now, I think that mixing the sachet plastic is the least of our worry.

How are they already combined? I agree that doing something is better than doing nothing, and I'm really happy to see and hear that there are people like you acitivly fighting the plastic problem. But I think at some point we should be focussing on long term circularity and for that its crucial that materials are not mixed.

sachet plastics are already combined. usually a foil with LDPE and PET

I think many sachets are from BOPP (biaxially oriented polypropylene) and aluminum.

Paul Bogaers

How are they already combined? I agree that doing something is better than doing nothing, and I'm really happy to see and hear that there are people like you acitivly fighting the plastic problem. But I think at some point we should be focussing on long term circularity and for that its crucial that materials are not mixed.

long term circularity with plastic will get you in trouble. I think optimism in the circularity of plastic is far too high. It's much better to produce a product that lasts a long time that is durable. The plastic problem is defined differently from person to person. It's my firm belief we work on the symptoms to the problem but really there needs to be products/material that move away from plastic and something more sustainable and less problematic. I want to run out of plastic to recycle.

3

Hmm okay, interesting take

Hi, I’ve previously been in contact with @Rory - Sustainable Design Studio regarding the production of an injection mould. Now I can not seem to get a hold of him anymore… Does anyone here know how I perhaps can reach him or what he is up to. OneArmy

Hey @M0lnet Seems we have reconnected.

1

Hi everyone, the workspace in Guwahati is trying out some old school compression moulding using the oven and mechanical compression. They have had the issue that the bowls that they are trying to make always turn out to have some deformities or holes in them. They are using PP, set the temperature to 230deg Celsius, and after melting in the oven let the bowl sit in the compression for 10 min. Subsequently they are cooling it down with water. Does anyone have any suggestions on how to optimise the process to not get the holes anymore? I am quite sceptical about the cooling down with water part.

10:19 AM

Nikolalelu

Click to see attachment 🖼️

Your moulds are filled but product has bubbles. I have the same issue with my low tech bowl pressing I do sometimes. Air bubbles always occur up near the lip/edge. I'm afraid I have no advice for this other than to prod the plastic before you press the mould into the plastic and check for bubbles. It may or may not be possible for you to do this

12:21 PM

And here's something for the extrusion folks. I don't think it's normally visible to see the flow of plastic through products but on this one you can. It flows like a river. Check this out, you can see the flow of the plastic through my planks. These are PP except for the brown.

OK so I have a question. I'm working on a product for a client but they're saying the surface is a little too slippery still. Does anyone have any suggestions? Heres a photo of extruded planks with a texture.

1

4:35 PM

The pattern is to help the plank be non-slip for walking on.

Maybe sandblasting can improve the grip, at least until the suface get worn.

10:26 PM

Sandblasting the mold, obviously

Hey i like to know about interlock using plastic

8:04 AM

Could you help me

Ben - Precious Plastic Ciledug

OK so I have a question. I'm working on a product for a client but they're saying the surface is a little too slippery still. Does anyone have any suggestions? Heres a photo of extruded planks with a texture.

How big are those squares?

Carolina

How big are those squares?

about 1.7cm x 1.7cm

sijo sam

Hey i like to know about interlock using plastic

Ask away and maybe someone will answer?

Ben - Precious Plastic Ciledug

about 1.7cm x 1.7cm

but you are trying to find a solution for the one on the picture, or a way to redesing the existing mould to improve the gripping?

sijo sam

Hey i like to know about interlock using plastic

you mean about interlocking systems with recycled plastic? like bricks?

Carolina

but you are trying to find a solution for the one on the picture, or a way to redesing the existing mould to improve the gripping?

Oh! I'm not going to lie, the mould was quite expensive. So i'm hoping i can find some solution for making the surface less slippery. I was hoping that these shapes would help, but it seems not enough. I might need something more textured. I'm half tempted to see if a meat tenderizer will work

Ben - Precious Plastic Ciledug

Oh! I'm not going to lie, the mould was quite expensive. So i'm hoping i can find some solution for making the surface less slippery. I was hoping that these shapes would help, but it seems not enough. I might need something more textured. I'm half tempted to see if a meat tenderizer will work

how big is the total surface?

Carolina

how big is the total surface?

1.5m x 10cm x 2cm is the plank size. The textured surface side is 1.5m x 10cm.

i think you might need to find ways to create even more texture on the small squares, options that i can think of on the top of my head: 1) sand it with a metal brush like the one for cleaning welds, either by hand or on a grinder (this is not ideal because of the microplastics, but if you do it in a closed space in where you can collect the particles later should be ok) 2) with a sharp knife make diagonal cuts in both directions. 3) maybe making some texture with a soldering iron (this might take long and probably wont be super aesthetic. *Solution for the mould itself would have been to make the squares as small as possible and making them less thick, they seem to stick out a lot, so they are not a texture anymore but almost like an elevated surface (if that makes sense)

1

Carolina

i think you might need to find ways to create even more texture on the small squares, options that i can think of on the top of my head: 1) sand it with a metal brush like the one for cleaning welds, either by hand or on a grinder (this is not ideal because of the microplastics, but if you do it in a closed space in where you can collect the particles later should be ok) 2) with a sharp knife make diagonal cuts in both directions. 3) maybe making some texture with a soldering iron (this might take long and probably wont be super aesthetic. *Solution for the mould itself would have been to make the squares as small as possible and making them less thick, they seem to stick out a lot, so they are not a texture anymore but almost like an elevated surface (if that makes sense)

That makes sense. Lots of food for thought. I need a solution that doesn't take too much time or effort but also is not bad to look at.

When I figure out what I'm going to do ill share.

Ben - Precious Plastic Ciledug

That makes sense. Lots of food for thought. I need a solution that doesn't take too much time or effort but also is not bad to look at.

When I figure out what I'm going to do ill share.

something tells me that there should something like a spray or a product you can use as "anti-slip"

something like this maybe? https://www.nonpaints.com/en/rust-oleum-supergrip-anti-slip-spray-in-500ml-aerosol

Rust-Oleum SuperGrip Anti-Slip Spray in 500ml Aerosol

5:00 PM

not sure whats the best one for plastic though

Does anyone have advice in terms of making tiles used for roofing, Or plastic solutions for roofs? Also looking to make crutches out of the plastic? Any advice?

Ben - Precious Plastic Ciledug

That makes sense. Lots of food for thought. I need a solution that doesn't take too much time or effort but also is not bad to look at.

When I figure out what I'm going to do ill share.

Have you considered texturing the beams with a fabric-like pattern? Perhaps use a low thread-count sheet with an iron and parchment paper. Put the sheet on the plastic and the parchment paper between the sheet and iron to keep any plastic from melting through the sheet into the iron. Should only take a few minutes per beam and provides a subtle but much less slippery surface?

NelsonMandela

Does anyone have advice in terms of making tiles used for roofing, Or plastic solutions for roofs? Also looking to make crutches out of the plastic? Any advice?

There is a few people that produce roofing material out of plastic, often mixed with sand. On YouTube, if you type recycled plastic roofing you should find some option. Where are you based ? Most of the things I saw were in west or south Africa, south-east Asia, or Russia. But in my knowledge I didn't see anyone from Precious Plastic doing saw, and for sure no open-source system.

Smarterer

Have you considered texturing the beams with a fabric-like pattern? Perhaps use a low thread-count sheet with an iron and parchment paper. Put the sheet on the plastic and the parchment paper between the sheet and iron to keep any plastic from melting through the sheet into the iron. Should only take a few minutes per beam and provides a subtle but much less slippery surface?

Interesting idea. That reminds me, there's some teflon cloth that might work well for this

Ben - Precious Plastic Ciledug

Oh! I'm not going to lie, the mould was quite expensive. So i'm hoping i can find some solution for making the surface less slippery. I was hoping that these shapes would help, but it seems not enough. I might need something more textured. I'm half tempted to see if a meat tenderizer will work

Maybe its an idea to add some sand to the plastic like the guy in #just-chatting did for his bricks?

Carolina

something tells me that there should something like a spray or a product you can use as "anti-slip"

something like this maybe? https://www.nonpaints.com/en/rust-oleum-supergrip-anti-slip-spray-in-500ml-aerosol

Something like this should work for a release spray

jensdb

Maybe its an idea to add some sand to the plastic like the guy in #just-chatting did for his bricks?

That doesn't work unless you melt the surface and toss sand on. If you extrude only plastic and have a smooth surface, you'll have almost the same surface texture as the plastic will fill in all the voids. And there's no way i'll be putting sand in my machine.

Alex_recycles and creates

Something like this should work for a release spray

This is the opposite of what I want. the discussion was more about how to make the surface more textured/non-slip

Ben - Precious Plastic Ciledug

That doesn't work unless you melt the surface and toss sand on. If you extrude only plastic and have a smooth surface, you'll have almost the same surface texture as the plastic will fill in all the voids. And there's no way i'll be putting sand in my machine.

You can do also the opposite. I'm wondering if heating sand and pour it on the plastic,then rinse with water can do the job...

heat the surface with a torch and toss dry sand on?

Hi, I'm trying to use some square box section aluminium tube (22mm x 22mm) to make short blanks that I can then turn into something else. I'm using a diy method - sandwich toaster to begin melting, and then popping gooey HDPE into the tube and putting that in a small oven. Once melted in my box section mould, remove from the oven and clamping with a stopper in the top and bottom to apply pressure whilst cooling. The process semi-works but the big issue is getting the cooled blank out of the tube. I've used a silicone release spray but that doesn't seem to help. Reheating / removing whilst warm seems like the best bet, but any other thoughts? Specifically - I understood that HDPE would shrink whilst cooling, so thought this would help, but I'm wondering if the aluminium expands and then shrinks more than the HDPE, leaving the plastic too tight inside? Might it be better to try a steel tube for this type of method? TIA

Hey everyone, I have a question. Last year I saw somewhere on instragram a workspace that had a mould for Christmas/winter ornaments. They had a star, a tree and a snowflake. For our workspace we are looking for something like that. Does anyone now where to find these moulds ? Or someone who can help us with making them?

Butte (PP Philippines)

We are starting to get more tech assistance from companies in the plastic industry lately. There is a lot we did not know before. For example de-gas the extrusion machine, we really need a method for the v4 machine to do this. We are finding big issues with moisture causing back pressure and preventing the machine from feeding the plastic. We are also working on getting some donations of older plastic molding and extrusion machines from some local plastic manufacturers. equipment that is a bit worn and not suitable for big production, but too valuable just to send for scrap.

You mention de-gassing. Has anyone done any work with vacuuming air / gas out of a mould while injecting?

11:51 AM

I mean within Precious Plastic.

Vincmer

Hey everyone, I have a question. Last year I saw somewhere on instragram a workspace that had a mould for Christmas/winter ornaments. They had a star, a tree and a snowflake. For our workspace we are looking for something like that. Does anyone now where to find these moulds ? Or someone who can help us with making them?

I used a silicone mould for this https://www.instagram.com/p/CWVbgKzvQR1/?igshid=MDJmNzVkMjY=

preciousplasticciledug

I'm not sure of the word for this but there's something kind of funny about having a plastic Christmas tree ornament that goes on a plastic Christmas tree. Anyways, these came out nicely.

Likes

104

Mortar Art (Melb, AU)

I mean within Precious Plastic.

nothing yet. with injection, bubbles are mainly caused by moisture. you need very very dry plastic. also plastic can absorb water. see the 3D printing world and all those filament dry issues.

You don't get it by trapping air during compression in your process?

3:21 AM

That was what I was assuming was causing my problems.

moisture makes steam, and then bubbles, just like a cake.

Aha.

3:22 AM

And I'm using hyrdoscopic PLA...

3:22 AM

For testing.

3:22 AM

I'll try drying it out next time. Do you have a favourite method for that?

I too was struggling with bubbles until i realized my issues were same as my 3d printing days. now that i use dry flake instead of the straight from the trash flake, my plastic lumber is dense

Cool! That's really good to hear, because I was having trouble figuring out how I could produce a good vacuum from moulds.

even when extrusion, i kept struggling, the machine would work well one day, then barely work next day.

3:26 AM

was getting steam blowing out of the hopper

3:26 AM

figured out that it was a vapor lock.

Yeah... that makes a lot more sense too, because the air pockets are often deep in my part.

3:27 AM

*gas pockets.

3:27 AM

And because I'm melting in the mould air has heaps of time to get out.

yesterday I was talking with a guy who builds the big plastic factories. we was discussing a possible purchase of a bigger commercial extrusion machine. he told me that I needed to set up a sort of tank, or bin that used a blower to suck plastic flake from the bottom, and deposit it back to the top of the bin, the air movement and flow of the plastic would dry the plastic.

3:29 AM

like attaching a dust collector to the bottom of a bin, sucking it out and blowing it back to the top of the bin

Ahhh.

all that movement and air flow to dry it

That should be easy to put together.

you could probably make a simple system with some 55 gallon drums welded end to end in a silo, and a 2hp sawdust collector

3:32 AM

that was my idea before, but now I reached the point of keeping a ton or more of plastic in stock, that idea is too small.

3:32 AM

so maybe a plywood and steel bin instead.

Yeah, for me I'd probably be doing about 20kg at once.

3:33 AM

So a 200lt drum should work.

for smaller batches... robot digg has a dryer

3:33 AM

1000usd from Shanghai.

3:34 AM

it looks very attractive for batch drying, but the customs fees to the Philippines will kill me

Usually that's not bad for me.

3:34 AM

How much would you have to pay there?

https://www.robotdigg.com/product/1380/25Kgs-or-50Kgs-Vertical-Hopper-Dryer

12Kgs, 25Kgs or 50Kgs Vertical Hopper Dryer - RobotDigg

Hopper dryer for extruder or injection molding machine Features: Hot air well-distribute heated wind. The heat efficienc...

3:35 AM

they would hit me maybe 500-600usd in tax and shipping at least

3:36 AM

300usd for 12 kilo size dryer plus shipping

3:36 AM

for injection mold that is plenty.

For me it's about 15% if customs stops it, but usually for stuff under $5k or so they don't.

i barely do 7-8 kilos in a full 8 hour shift for injection mold

Even though they changed the rule to $1,000aud.

Butte (PP Philippines)

i barely do 7-8 kilos in a full 8 hour shift for injection mold

My plan for the initial pilot run of formwork is to make 10 bricks a day.

3:37 AM

They're 2.1kg each if it's PLA, 1.6 if it's HDPE.

of course just keep in mind that at that rate of production, it is your experimental and learning phase.

3:39 AM

after that you will have to go bigger to make it cost effective in electric usage and labor. that is where we managed to get to the last few months. learning the techniques and details not in Daves videos

Yeah. For proof of concept (for the formwork) I just want to get a batch out relatively quickly.

I understand

It'll still take about a month of full time work, but there's no other way to do it.

3:40 AM

But after that, I am thinking to try to build an automated tool.

You can either buy your way into it, or work your way into it.

3:41 AM

all our working funds are from work... lol machine sales, product sales

3:42 AM

Mad science in the shop is not cheap... but you can trade labor for results.

I've got some tentative funding to demonstrate an alternative to formply.

nice

Already took a decent amount of labour to get to this point.

3:42 AM

But I got sidelined by COVID for a few months.

3:43 AM

Was too exhausted to do metalworking.

we have been struggling with putting together a business plan for the next level. Covid stole 2+ years of progress from us.

3:44 AM

We was selling a shredder a week, and had nearly enough to buy a 3 car garage shop space. then the lockdowns and we got down to our last 20USD for awhile.

Damn.

3:45 AM

Have you got any connections with the construction industry there?

yes

You already do plastic lumber right?

although most business now is NGO,

3:46 AM

Plastic lumber, eco pots, and soap cases

Long, flat plastic boards are an instant drop in for formply.

3:46 AM

And there are global shortages.

my next order for lumber in the pipeline is for walkways.

I'm trying to target structural formwork, which is much higher end / more expensive.

here in some areas there are eco resort areas,

3:48 AM

and the only access is via elevated walkway thru mangrove swamps. otherwise people will damage the area

Aha! Yeah, they often do similar in national parks here.

3:48 AM

The irony is the areas become kind of inaccessible without the walkways.

Nice.

3:50 AM

I'd love to visit some day. Seems like a beautiful country.

the problem is they are bamboo and rot fast.

3:50 AM

this is the beach at the end of the walkway

Butte (PP Philippines)

the problem is they are bamboo and rot fast.

Is bamboo grown locally?

the problem is the trash makes everything look terrible here.

3:51 AM

bamboo is like a weed here.

3:52 AM

the entire country is covered in trash. people do not care for the most part.

Butte (PP Philippines)

the problem is the trash makes everything look terrible here.

Yeah, I've noticed that Philippines seems to have a bit of a problem with that compared to some other Asian countries.

the ocean around the country, I observed on a boat trip last month was a soup of plastic trash (edited)

3:54 AM

Indonesia is maybe a little similar.

But on the other hand.... Plastic is money and has value... free money just in the street waiting for someone to pick it up

Yeah. That's sort of the angle of a lot of these projects.

4:00 AM

Or at least the enabling factor. Which plastics do you use the most?

HDPE, PP

Never PET?

We hopefully will start working on PET, but only as a funding source.

Oh, as in like you'd be paid to take care of it.

We started working with a soft drink company and they will buy all the PET we can supply

4:06 AM

so as a consolidator between the street collectors, and trash trucks, there is a niche available

Ah, yeah, so that's going to be highly specific to the local economy.

and logistics/energy issues

I plan to try to make a brick out of PET, but partly because I want a clear one.

4:07 AM

At least to see how it looks.

PET is like water when melted

4:07 AM

and brittle when hard again

Low viscosity is good for me. Brittle is not.

4:08 AM

My first bricks cracked into pieces, but I now suspect that's because the plastic was wet.

it is also breaks down easy in sunlight

That's not ideal for use in formwork...

you could make fiber more easily with it

4:08 AM

see andry kolev on youtube

4:09 AM

he extrudes it and has a blower under the extruder nozzle

4:09 AM

the PET blows away from the machine, looks like fiberglass

4:09 AM

he runs the machine around 280c

Yeah, PET has high processing temps.

I built a PET fiber machine years ago

4:12 AM

but I used a heated nozzle like a spray gun.

4:13 AM

it did not work well.

4:13 AM

Andreys design is way better

4:13 AM

i kept burning the heaters in the part that heated the compressed air.

4:14 AM

maybe if I had built andreys current design it would have worked (edited)

I'll check out his designs today.

4:18 AM

What's the end use for the fibre?

4:24 AM

A PET wool substitute?

Mortar Art (Melb, AU)

A PET wool substitute?

yes.

Hello, Has any videos or content been published to do with these rocks making them ect, this one was featued in pp part 5.2, thanks

Is it possible to purchase or have a mold made for a one off project?

HappyN00dl3

Is it possible to purchase or have a mold made for a one off project?

You can ask sellers on the bazar https://bazar.preciousplastic.com/

Precious Plastic Bazar

Plastice to sell products, machines, and plastic. Empowering our recycling ecosystem around the world.

HappyN00dl3

Is it possible to purchase or have a mold made for a one off project?

Or you can ask machine builders around you on the map https://community.preciousplastic.com (edited)

Precious Plastic Community

A series of tools for the Precious Plastic community to collaborate around the world. Connect, share and meet each other to tackle plastic waste.

Searching for an information. Someone knows what is the optimal pressure for the plastic during injection? I'm adding some modifications to my DIY press to add an injector. Since I found a good hydraulic pump that meet my needs (I have some electric power limitations in the laboratory, that is the main reason why I made the first version of the press with a 16bar pump making a pressure booster cylinder from scratch), a NOS Parker pump with a 0.8cc/rev displacement, capable to up to 280bar pressure with the right flow for my 50mm cylinder, I decided to modify the system. From my calculations, using a 30mm ID barrel for the injection, with 200bar oil pressure I can reach up to 550bar in the injection barrel. Seems to be more than enough, but I don't have experience in this topic. I want to make some thin parts (something like 5x30x130mm in the thinner zone) for a project I started with a childhood friend I met after decades...more info in next months.

1

Davide->PreciousPlasticRomagna

Searching for an information. Someone knows what is the optimal pressure for the plastic during injection? I'm adding some modifications to my DIY press to add an injector. Since I found a good hydraulic pump that meet my needs (I have some electric power limitations in the laboratory, that is the main reason why I made the first version of the press with a 16bar pump making a pressure booster cylinder from scratch), a NOS Parker pump with a 0.8cc/rev displacement, capable to up to 280bar pressure with the right flow for my 50mm cylinder, I decided to modify the system. From my calculations, using a 30mm ID barrel for the injection, with 200bar oil pressure I can reach up to 550bar in the injection barrel. Seems to be more than enough, but I don't have experience in this topic. I want to make some thin parts (something like 5x30x130mm in the thinner zone) for a project I started with a childhood friend I met after decades...more info in next months.

just for you to have an idea, the lever injection machine reaches up to 43 bars and other arbor design up to 75 bars. Just keep in mind that if you go much higher in pressure you'll need much much stronger moulds, so be careful with that!

Carolina

just for you to have an idea, the lever injection machine reaches up to 43 bars and other arbor design up to 75 bars. Just keep in mind that if you go much higher in pressure you'll need much much stronger moulds, so be careful with that!

Thank you a lot for the informations! I don't need to go at excessive pressures, I was wondering about what I can achieve. I found some papers about industrial machines, and they start around 450bar, but obviously industrial molds and machines are just a little more robust than mine (I'm working in a factory that make industrial mold holders and sliders so I know what they are!

), but nothing about the PP machines. I can start at a lower pressure, I can adjust it from 0 to 280bar in the cylinder, and then I have to check the result. Speaking about the strenght of the molds, I think there aren't problem, since I make them how I want!

Thank you!

I'm not sure if this is the right section, but this video described techniques to make a nice polished surface, which was something I was seeking methods to do for the steel plates in my moulds; https://www.youtube.com/watch?v=7B5u5cMBNrI

adam the machinist

Improve your polishing with 3D printing

1

where can we buy the stamp coins? on bazar they only have an indian supplier but they do not ship to belgium?

9:25 PM

What do you think about this mould?

3

9:25 PM

Amazing design

5

1

2

tomi.machuca

Click to see attachment 🖼️

wow!!

How-to?

1

do created with colaborators that study industry design

1:19 PM

The material is aluminium

Very beautiful mold! Can't wait to see the product!

Davide->PreciousPlasticRomagna

Very beautiful mold! Can't wait to see the product!

7

2

Hi there! I'm new to this whole space and was wondering what software you'd recommend for making a mold. I currently am using Blender and didn't know if there was another free open source program out there.

Ben Atlas Games

Hi there! I'm new to this whole space and was wondering what software you'd recommend for making a mold. I currently am using Blender and didn't know if there was another free open source program out there.

SolidWorks came to my mind but I guess there is only a demo free version you open using your browser

1

Ben Atlas Games

Hi there! I'm new to this whole space and was wondering what software you'd recommend for making a mold. I currently am using Blender and didn't know if there was another free open source program out there.

Fusion 360 from Autodesk is free for personal use, or startups for a year. They really try to get you to pay for it, but I've been using it for free for 3 years now.

7:57 PM

The cheapest SolidWorks option is a $99 annual maker license

7:58 PM

https://www.autodesk.com/products/fusion-360/personal

Erik72

Fusion 360 from Autodesk is free for personal use, or startups for a year. They really try to get you to pay for it, but I've been using it for free for 3 years now.

thanks I'll look into that. I read somewhere that people didn't recommend Blender to make a mold. Is that outdated or is this still something that would be recommended?

Ben Atlas Games

thanks I'll look into that. I read somewhere that people didn't recommend Blender to make a mold. Is that outdated or is this still something that would be recommended?

I have not used Blender very much at all, but I feel it's better suited to "pure digital" creations and animations? F360/SW are specifically built to integrate with physical manufacturing.

2:23 PM

TinkerCAD is an option also

Thanks for the answer

Hi everyone, we're working on making an aluminium pot mould for a school and we've heard that having surface roughness (as opposed to a mirror finish) helps the part not stick to the mould. I've seen that we can use a sandblaster with glass beads to roughen it and also we could acid etch it but is there an easier way to roughen the surface that you are employing?

Ben Atlas Games

thanks I'll look into that. I read somewhere that people didn't recommend Blender to make a mold. Is that outdated or is this still something that would be recommended?

With Blender you have to build in settings and and be very careful about your unit of measurement, and it isn't as easy to export files for production. Can you do it? Yes, but it is generally a thing that folks take on when they are already familiar with Blender, like 10-15 years ago when not much was out there at all.

1

Awesome info to know.gonna check out fusion 360

1

Depends on what you're doing and how you're doing it. If you're wanting to do a somewhat simple 2.5d design, you can use http://easel.inventables.com

Just a thought, but referring to the most durable use of plastic as the construction building, has anybody tought about producing the so called "iglu", that is a 3d arch-shape (check the link) to be embedded in pavements and foundations for various advantages (isolation, ventilation, savings on materials etc), check the website https://www.daliform.com/en/iglu-ventilated-under-floor-cavity/

dg-admin

Iglu'® ventilated cavities | Daliform Group

Disposable formwork for ventilated under-floor cavities, sanitary spaces, ventilated cavities, ventilated floors and ventilated roofs.

3:07 PM

blastic

Just a thought, but referring to the most durable use of plastic as the construction building, has anybody tought about producing the so called "iglu", that is a 3d arch-shape (check the link) to be embedded in pavements and foundations for various advantages (isolation, ventilation, savings on materials etc), check the website https://www.daliform.com/en/iglu-ventilated-under-floor-cavity/

Yes, I do. But it is more like an industrial product rather than something you can make in a small workspace.

1

8:45 PM

I also thought to remove the dozen of them sitting in construction site of a building of a bankrupt company near my home to have some raw material...

Davide->PreciousPlasticRomagna

Searching for an information. Someone knows what is the optimal pressure for the plastic during injection? I'm adding some modifications to my DIY press to add an injector. Since I found a good hydraulic pump that meet my needs (I have some electric power limitations in the laboratory, that is the main reason why I made the first version of the press with a 16bar pump making a pressure booster cylinder from scratch), a NOS Parker pump with a 0.8cc/rev displacement, capable to up to 280bar pressure with the right flow for my 50mm cylinder, I decided to modify the system. From my calculations, using a 30mm ID barrel for the injection, with 200bar oil pressure I can reach up to 550bar in the injection barrel. Seems to be more than enough, but I don't have experience in this topic. I want to make some thin parts (something like 5x30x130mm in the thinner zone) for a project I started with a childhood friend I met after decades...more info in next months.

I started out with the manual machine, but for production it is exclusively the 5 ton hydraulic low splitter mod to injeciton mmolder. Even then, it depends on the plastic. PP is the easiest to get a good result, although even there your donor material can vary in regards to sinkage issues. HDPE is much more difficult to mold and at at the beginning I did not know there was a difference between blow mold hdpe and injection hdpe so i had a huge amount of unnecessary problems. Blow mold HDPE even at 5 tons pressure is like trying to inject a gummy bear. it is possible but not easy and you need HUGE clamping force. I literally blew apart several molds with blow mold grade stuff.

2

Thank you for the feedback! What is the injector diameter? And what is the nozzle diameter? Did mixing blow molding HDPE with injection molding one make some differences? I'm asking, because as usual I'm making the machine with a different design.

at least 20% of the injection mold HDPE with the blow mold plastic, and ideally 50/50

8:09 AM

blow mold hdpe is better suited to use as a engineering plastic for machining, it is a ultra high molecular weight HDPE. If you can produce good solid beams without air bubbles, it will find a ready market with machine shops

2

More golf course sand box orders. We are improving our product by using a wood plane to smooth the surface chamfer the corners, and a blow torch to flame polish the rough parts. Also by using dryer plastic we have eliminated the big bubbles we had before. (edited)

4

First sheets in Bali

️

7

2

Hello @Butte (PP Philippines)! I saw you talking about blow mould HDPE and that was not anything I have heard about until now. We have just gotten our manual plastic injection machine and are making rings out of recycled HDPE in form of bottle caps and milk jugs. We have trouble filling our moulds whenever we use the milk jugs and as of reading your post and with a few Google searches I suspect they are blow mould HDPE. I understand you have a bit of experience regarding this, so do you think there is any way for us to still use blow mould HDPE or is it impossible with a manual injection moulding machine?

Butte (PP Philippines)

I started out with the manual machine, but for production it is exclusively the 5 ton hydraulic low splitter mod to injeciton mmolder. Even then, it depends on the plastic. PP is the easiest to get a good result, although even there your donor material can vary in regards to sinkage issues. HDPE is much more difficult to mold and at at the beginning I did not know there was a difference between blow mold hdpe and injection hdpe so i had a huge amount of unnecessary problems. Blow mold HDPE even at 5 tons pressure is like trying to inject a gummy bear. it is possible but not easy and you need HUGE clamping force. I literally blew apart several molds with blow mold grade stuff.

Super Precious info, thanks for sharing

M0lnet

Hello @Butte (PP Philippines)! I saw you talking about blow mould HDPE and that was not anything I have heard about until now. We have just gotten our manual plastic injection machine and are making rings out of recycled HDPE in form of bottle caps and milk jugs. We have trouble filling our moulds whenever we use the milk jugs and as of reading your post and with a few Google searches I suspect they are blow mould HDPE. I understand you have a bit of experience regarding this, so do you think there is any way for us to still use blow mould HDPE or is it impossible with a manual injection moulding machine?

Milk jugs are blow molded

Davide->PreciousPlasticRomagna

I also thought to remove the dozen of them sitting in construction site of a building of a bankrupt company near my home to have some raw material...

I know that feeling

Also you have got a magical supershredder that could do the job very well

Davide->PreciousPlasticRomagna

Yes, I do. But it is more like an industrial product rather than something you can make in a small workspace.

Yes i was thinking to a project similari to the Plastic brick. Also they are made with the extruder in big molds

M0lnet

Hello @Butte (PP Philippines)! I saw you talking about blow mould HDPE and that was not anything I have heard about until now. We have just gotten our manual plastic injection machine and are making rings out of recycled HDPE in form of bottle caps and milk jugs. We have trouble filling our moulds whenever we use the milk jugs and as of reading your post and with a few Google searches I suspect they are blow mould HDPE. I understand you have a bit of experience regarding this, so do you think there is any way for us to still use blow mould HDPE or is it impossible with a manual injection moulding machine?

you have to thin the blow mold stuff with injection mold plastic or maybe PP

there is also a blow mold ldpe. either way it is a thick plastic like a gummy bear when hot, that is so they can blow it up like blowing a bubble in chewing gum. same plastic but they link the molecules in a longer chain by using heat and catalysts during the manufacturing process.

1

Hye everybody. I have a startup who wants to start creating flowerpots and soap dishes but i am no designer. So iam looking for someone who can make moulds and help design them. Hit me up if you help!

blastic

I know that feeling

Also you have got a magical supershredder that could do the job very well

It has to prove it's superiority. I'm going to finish it in these weeks.

1

Butte (PP Philippines)

there is also a blow mold ldpe. either way it is a thick plastic like a gummy bear when hot, that is so they can blow it up like blowing a bubble in chewing gum. same plastic but they link the molecules in a longer chain by using heat and catalysts during the manufacturing process.

Did you have suggestions about blow molding and thermoforming polypropylene? I collected some, but from the first tests it seems to be very fluid when melted.

Hi! I was looking for a sheetpress channel but it seems there is none. So I'm just going to throw this here and hope someone will be able to help me :) Last week and this week, my sheets came out of the press with lot of "holes". I didn't have that problem before and I'm not sure what could cause them. I'm thinking maybe :

air bubbles? But why now and never before
change of temperature (difference between outside and sheetpress temperature) or humidity ?

... Did anyone already had the same problem and discovered the reason? Thanks for your help!

11:45 PM

11:46 PM

You can see here the "holes", a bit like the surface of the moon.. as if something had poked the sheet..

Marie.Pan

Hi! I was looking for a sheetpress channel but it seems there is none. So I'm just going to throw this here and hope someone will be able to help me :) Last week and this week, my sheets came out of the press with lot of "holes". I didn't have that problem before and I'm not sure what could cause them. I'm thinking maybe :

air bubbles? But why now and never before
change of temperature (difference between outside and sheetpress temperature) or humidity ?

... Did anyone already had the same problem and discovered the reason? Thanks for your help!

were you using the same plastic as before?

Marie.Pan

You can see here the "holes", a bit like the surface of the moon.. as if something had poked the sheet..

holes? Do you mean bubbles? Your photos are showing that it looks like you filled it properly. There's no flow/movement in the plastic so i'm a bit curious how you're pressing it. Some people make the mistake of pressing with a lot of force before things start melting and this can cause air to become trapped. Trapped air is hot and as it cools it will create a vacuum and pull down on the plastic which will cause these depressions. I think everyone struggles to make sheets with no trapped air, but you need to try your best to be as consistent as possible, that way if there's any variables you can quickly figure out what it was. (Plastic source, time on machine, temperature, type of plastic, color of plastic, wet plastic, is it windy?, what demoulding agent were you using?, etc etc...)

/Hello everyone! I work for a company that uses biocomposite (wood waste) as a material for one of its products. I wonder if anyone has any experience using this material on the machines. If so, I would love to hear about your experience. Looking forward to reading your messages!

Leonor

/Hello everyone! I work for a company that uses biocomposite (wood waste) as a material for one of its products. I wonder if anyone has any experience using this material on the machines. If so, I would love to hear about your experience. Looking forward to reading your messages!

Go to #archived-beyond-plastic

Carolina

Go to #archived-beyond-plastic

Hi Carolina! Already did, however, I haven't gotten any answer, hence I tried on a different group

Thank you!

Hello everyone, I am looking for a sturdy modular toolbox storage system. Something similar in quality to the "Milwaukee Packout" or "Systainer" Systems. Please let me know if you have heard of anything or if someone is motivated to design something that can be opensourced. I should be able to get some dollars together to pay for it. Cheers Hannes

Is there in this channel a good mould maker? We need a flowerpot mould, but the distributors in our country aren't cooperating because our machine is too different. Kind regards in advance

Joey

Is there in this channel a good mould maker? We need a flowerpot mould, but the distributors in our country aren't cooperating because our machine is too different. Kind regards in advance

Hello, I would recommend you to contact https://easymoulds.de/ or https://plasticpreneur.com/ . I have very good experience with moulds from these guys PreciousPlastic

Work

The various services easymoulds offers to our customers

admin

plasticpreneur - plastic recycling solutions

We develop and provide small-scale plastic recycling solutions and combine them with social entrepreneurship skills to generate positive impact.

1

Marie.Pan

Hi! I was looking for a sheetpress channel but it seems there is none. So I'm just going to throw this here and hope someone will be able to help me :) Last week and this week, my sheets came out of the press with lot of "holes". I didn't have that problem before and I'm not sure what could cause them. I'm thinking maybe :

air bubbles? But why now and never before
change of temperature (difference between outside and sheetpress temperature) or humidity ?

... Did anyone already had the same problem and discovered the reason? Thanks for your help!

wet plastic, steam bubbles

3:35 AM

we are making a different brick design, it fills the mold like the plastic lumber. no cnc parts, just standard dimension flat bar stock, tubular stock and angle bar stock.

3:36 AM

the bottom extends out slightly to make a drip overhang. hopefully to prevent water from entering thru the wall so easily. we will be testing this today. wish us luck

5

Butte (PP Philippines)

the bottom extends out slightly to make a drip overhang. hopefully to prevent water from entering thru the wall so easily. we will be testing this today. wish us luck

Very interesting design. Good luck! Only a suggestion, find a better welder...

Davide->PreciousPlasticRomagna

Very interesting design. Good luck! Only a suggestion, find a better welder...

i do what i can with the guy. he is $12 a day we wasnt finished welding when the pic was taken. (edited)

Butte (PP Philippines)

i do what i can with the guy. he is $12 a day we wasnt finished welding when the pic was taken. (edited)

I understand. Maybe you can pay someone to teach him.

Hello Friends - my struggle with mould release continues. I tried extruding shredded curd containers (PS) but the lumber is stuck in the mould and not coming out. I tried using vegetable oil for greasing the mould from inside but it seems to not have workded. I am using iron moulds. Any suggestions friends on where am I going wrong?

Priyank Mishra

Hello Friends - my struggle with mould release continues. I tried extruding shredded curd containers (PS) but the lumber is stuck in the mould and not coming out. I tried using vegetable oil for greasing the mould from inside but it seems to not have workded. I am using iron moulds. Any suggestions friends on where am I going wrong?

hello! So there are are a few things that might be causing the problem. 1. if its the white PS containers, these are generally HIPS (high impact polystyrene) which on my experience is much tougher to work with 2. PS in general has a very low shrinkage rate (~0.5%) unlike PP or HDPE (2.6% and 3.3%) 3. If you really want to try making beams with it try with smaller lenght (less than 1 m) that might make it easier to take out of the mould 4. for mould releaser we generally use silicon oil or WD-40 5. whats the shape of your mould? and whats the thickness of the walls? (if its too thin it might deform while extruding, making it impossible to demould) (edited)

1

the work continues on our brick molds.

6

1

Butte (PP Philippines)

the work continues on our brick molds.

How was the unmolding with this complex shape ? It didn’t shrink too much around the tube inside ?

Butte (PP Philippines)

the work continues on our brick molds.

wow! that worked pretty nicely, i thought some plastic could leak under the beam that makes the slot since it wasnt welded all the way. Did you try making another one to see how they fit together?

I would like to know if anyone has built a Noggles injection mould from NounsDAO?

Carolina

wow! that worked pretty nicely, i thought some plastic could leak under the beam that makes the slot since it wasnt welded all the way. Did you try making another one to see how they fit together?

it was changed to a thicker 1x1 inch tube for the slot, fully welded and fillet grind with the angle grinder

12:42 AM

that is third attempt, it was shortened to 12 inch length because 24 inch was too much friction to push out.

12:43 AM

fourth attempt once we for the release to work, we changed the fit of the tongue making it slightly larger than the bottom groove. it is now a force fit with a rubber hammer.

https://www.youtube.com/watch?v=4yziZQjEY4w

Precious Plastic Philippines

recycled brick plastic

Video on making steel trays/boxes, with a jig design that I thought others might find useful for simple mould making: https://www.youtube.com/watch?v=yrb1Oh0aJM4

Pask Makes

How to Make Useful Steel Boxes - Simple Jig with No Folding Equipme...

1

Carolina

hello! So there are are a few things that might be causing the problem. 1. if its the white PS containers, these are generally HIPS (high impact polystyrene) which on my experience is much tougher to work with 2. PS in general has a very low shrinkage rate (~0.5%) unlike PP or HDPE (2.6% and 3.3%) 3. If you really want to try making beams with it try with smaller lenght (less than 1 m) that might make it easier to take out of the mould 4. for mould releaser we generally use silicon oil or WD-40 5. whats the shape of your mould? and whats the thickness of the walls? (if its too thin it might deform while extruding, making it impossible to demould) (edited)

Thanks Carolina. Trying a shorter beam worked. Aslo steel moulds with bit of vegetable oil giving better results.

1

Ben - Precious Plastic Ciledug

OK so I have a question. I'm working on a product for a client but they're saying the surface is a little too slippery still. Does anyone have any suggestions? Heres a photo of extruded planks with a texture.

Hi Ben, just wondering if you got this sorted? There are a couple of things i might suggest. Let us know how you resolved it.

Geoff (PBI NTB)

Hi Ben, just wondering if you got this sorted? There are a couple of things i might suggest. Let us know how you resolved it.

Although a little inefficient, using a heat gun and pressing in different textured surfaces helped. I used a noodle cutter and also a meat tenderizer to test. Haven't asked/heard back from the client yet though.

3:20 PM

I'll share the results first thing in the morning for me

Hey! Is it possible to create cardboard out of mangoes or oranges?

Ben - Precious Plastic Ciledug

Although a little inefficient, using a heat gun and pressing in different textured surfaces helped. I used a noodle cutter and also a meat tenderizer to test. Haven't asked/heard back from the client yet though.

In a previous job for non-slip flooring we use epoxy resin and then throw fine quartz over it. Was thinking maybe using the heatgun to soften, then some sand or quartz into the raised plastic squares. Otherwise, mod the mould (if possible) with a dremmel tool to create texture.

Jakob

Hey! Is it possible to create cardboard out of mangoes or oranges?

Great question for #archived-beyond-plastic

https://youtube.com/shorts/P3KSN5vl0aE processing molded parts. 650 shampoo bar cases takes a little less than 2 weeks.

Precious Plastic Philippines

triming

Butte (PP Philippines)

https://youtube.com/shorts/P3KSN5vl0aE processing molded parts. 650 shampoo bar cases takes a little less than 2 weeks.

Just a suggestion. Have you tried vargus shaviv deburring tools? I use them in metalworking since over 20 years at now, there are lots of blade shape, and they are really useful on plastic, for my little experience on it.

1

Hi everyone, what is the best way to print on hdpe in your experience? Tried UV printing but it comes of rather easily

1

Doruk Yıldırım

Hi everyone, what is the best way to print on hdpe in your experience? Tried UV printing but it comes of rather easily

?

Hi all! I have been experimenting with bits of old crayons and silicone molds to make crayons with embedded designs. I've been wondering if I could replicate this process to make recycled plastic objects using a series of injection molds. Does anyone know if it's possible to embed a plastic piece (maybe with adhesive or a snug cavity?) into a mold and inject around it? Or if there would be heat/pressure issues that would ruin anything already in the mold or cause other tragedies?

3:35 AM

I've used a similar process to salvage excess activated Jesmonite (polymer-modified plaster) so it doesn't go to waste, and I love the range of unpredictable results in the color and pattern combinations! Would love to try making block sets using plastic shreds.

(edited)

3

Doruk Yıldırım

Hi everyone, what is the best way to print on hdpe in your experience? Tried UV printing but it comes of rather easily

I've had a few friends suggest UV printing, however, the plastic they print on isn't textured. They dont seem to have any issues, but they recommend extra drying time for the process. If you rush it, it will get messy. Your other alternative is to use stickers. But UV printing looks very clean...hard to beat i think.

Davide->PreciousPlasticRomagna

Very interesting design. Good luck! Only a suggestion, find a better welder...

That inside piece looks galvanized (white burned off zinc on the inside) and it looks like flux wire, it's not the best but it's not going to look pretty with those resources

waterppk

That inside piece looks galvanized (white burned off zinc on the inside) and it looks like flux wire, it's not the best but it's not going to look pretty with those resources

Zinc has to be removed before welding to avoid health issue (did you ever have had zinc fever?) and welding of parts subjected to pressure has to be made with knowledge to avoid risk. Doesn't need to look pretty, it does have strenght (and maybe to avoid poisoning of the welder).

Does anyone have a filament spool mould? Makes heaps more sense than buy them or 3D printing them.

bookymargoof

I've used a similar process to salvage excess activated Jesmonite (polymer-modified plaster) so it doesn't go to waste, and I love the range of unpredictable results in the color and pattern combinations! Would love to try making block sets using plastic shreds.

(edited)

very cute!

Anyone North/South American individuals/groups selling compression sheet molds? There are a few on the PP bazaar but they're all in Europe or Asia with super high shipping costs (+lots of shipping emissions!)

12:45 AM

12:49 AM

First injection mold made, for small plant pots of 70mm diameter x 70mm high. I wanted to do something different than the common conical ones, here I made the exterrnal diameter cylindrical, and only the internal part have a 2°taper in total. Since the taper is less than average (I can correct it if needed) I put the ejection pin in the middle. It is spring loaded and it has +/- 5 mm stroke.

12:52 AM

Surface seems rough on photo, but they aren't, it is an optical issue. Made with C45 - EN 10083 steel.

Second one. Just another hexagon tile mold, but I made some modifications. I read that someone had problems keep the tiles sticking on the wall, so I decided to try to add some little spacers on the side. They are 2.5mm thick and they protrude from the sides 4mm. I made them to help to keep the distance between the tiles during installation, and they also lock the tiles when incorporated in the grout, no matter if it is made with resins (I'm wondering using black poliurethane sealant to glue them on the wall) or adhesives or probably also the normal tile grout.

12:51 AM

1

12:52 AM

I also made the back plate convex to make the tile concave, to help it sticking on the wall thanks to vacuum. I'm waiting to complete the injector and the shredder to test them.

12:53 AM

All made on CNC lathe with live tooling (Mori Seiki NL2500).

12:56 AM

Finish would seems rough even here on the external face side, but it is so smooth, after one hour of oil stone and abrasive paste...just a matter of light reflection. On the rear I made it rough on purpose.

Has anyone tried making weight plates with recycled plastics? They are in high demand and could use up a lot of material. Obviously these are for concrete, but picture metal moulds that are properly sized to reach the desired weights.

1

any suggestions to create a DIY coaster or stool mould for a personal project scale?

4:56 PM

I'm new in this world of recycling

Halcyon2024

any suggestions to create a DIY coaster or stool mould for a personal project scale?

Ok personally I wouldn’t do a mold because it would have to be a pretty big mold. I would use a extruder to make the legs (rectangular beams) and a sheet press to make he part you will sit on. You’d an cut the sheet press with a saw or something to make it round or what ever shape you desire. (edited)

Today I tested my injection machine. Seems working fine, I made some hexagonal test tiles with the mold I made this week. First one came out incomplete, others came out a lot better. Not the coolest colors since I had limited amount of shredded material, but enough to test it. I can't find any chart for right temperatures. I started with 180°C barrel and 200°C nozzle, and then I cranked up to 225°C barrel and 250°C nozzle. With higher temps seems working better. ~330bar inejction pressure. Any suggestion is highly appreciated. PS:I didn't try to make pots because I forget to take in account that barrel lenght increases with heating...I made the mold to slide precisely under the barrel, but with it in temperature they collide, it is matter of half a mm or less. Tomorrow or monday I give it a touch on the lathe to make it fit as needed...

12:01 AM

MIfoodie

Ok personally I wouldn’t do a mold because it would have to be a pretty big mold. I would use a extruder to make the legs (rectangular beams) and a sheet press to make he part you will sit on. You’d an cut the sheet press with a saw or something to make it round or what ever shape you desire. (edited)

I’m planning to use mould for smaller items

i see. an extruder would make a more sturdy leg

MIfoodie

Ok personally I wouldn’t do a mold because it would have to be a pretty big mold. I would use a extruder to make the legs (rectangular beams) and a sheet press to make he part you will sit on. You’d an cut the sheet press with a saw or something to make it round or what ever shape you desire. (edited)

You’ve also created furniture with recycled plastic?

Halcyon2024

You’ve also created furniture with recycled plastic?

I haven’t.

cwakeman

Anyone North/South American individuals/groups selling compression sheet molds? There are a few on the PP bazaar but they're all in Europe or Asia with super high shipping costs (+lots of shipping emissions!)

You may message us through the bazar, we aré in México

anyone ever made DIY moulds with concrete? lol (edited)

Halcyon2024

anyone ever made DIY moulds with concrete? lol (edited)

No, but this doesnt seem like a totally crazy idea to me. There are different kinds/grades of concrete, and with a fine particle size and good amount of reinforcement like glass fiber it might even work. It would be hard to get close tolerances so you'd have flash to trim. I'm very curious now..

Halcyon2024

anyone ever made DIY moulds with concrete? lol (edited)

I used plaster of paris once. Worked ok, but it's only good one time because it's a bit too fragile. Concrete might work but you need to make sure to get all the moisture out first. I got a long list of things to try and one of them is to make a ceramic mould. Nothing too crazy but basically just find a ceramic studio that does pottery and such and i think you should be able to make a very nice and sturdy mould. If done right, you can glaze the ceramics and get a really smooth surface so you wont have plastic sticking in all the wrong places. You might be able to get away with making a nice mould from something that's bisque fired and then putting a light coat of epoxy on it. Ah, so many things to try. (edited)

is there any followup tutorials on this one?

Davide->PreciousPlasticRomagna

Today I tested my injection machine. Seems working fine, I made some hexagonal test tiles with the mold I made this week. First one came out incomplete, others came out a lot better. Not the coolest colors since I had limited amount of shredded material, but enough to test it. I can't find any chart for right temperatures. I started with 180°C barrel and 200°C nozzle, and then I cranked up to 225°C barrel and 250°C nozzle. With higher temps seems working better. ~330bar inejction pressure. Any suggestion is highly appreciated. PS:I didn't try to make pots because I forget to take in account that barrel lenght increases with heating...I made the mold to slide precisely under the barrel, but with it in temperature they collide, it is matter of half a mm or less. Tomorrow or monday I give it a touch on the lathe to make it fit as needed...

Dude! The job what you do is amazing

Oscar Cornejo

Dude! The job what you do is amazing

Thank you man!

6:02 AM

I also tested the plant pots mold.

6:03 AM

1

You know that those plant pots reminds me the thrill pipe caps and those are expensive

@primordialgrue @Ben - Precious Plastic Ciledug My plan is to create a mixture of cement with fine sand particles. Use silicone spray on the object that I would like to mould in so hopefully it doesn't stick to the concrete. I'm planning to do some experiment, will update on the results.

Davide->PreciousPlasticRomagna

I also tested the plant pots mold.

can you share the pot moulds picture? what material does it use?

Halcyon2024

can you share the pot moulds picture? what material does it use?

You're welcome

Oscar Cornejo

You know that those plant pots reminds me the thrill pipe caps and those are expensive

What are thrill pipe?

Davide->PreciousPlasticRomagna

You're welcome

very nice! looks good

Halcyon2024

very nice! looks good

Thanks!

Halcyon2024

can you share the pot moulds picture? what material does it use?

I forgot to mention the material. Molds are made from C45 or 1.0503 (AISI 1045) steel. Pots are made with HDPE but I want to make them also (or mainly) in PP.

Davide->PreciousPlasticRomagna

I forgot to mention the material. Molds are made from C45 or 1.0503 (AISI 1045) steel. Pots are made with HDPE but I want to make them also (or mainly) in PP.

that's industrial grade type of equipment. This is no longer a hobby for you is it? haha

Original message was deleted or could not be loaded.

oh no, I'm just amazed with the equipment being used bcs I'm still on a DIY level trying to create small stuff

7:00 PM

hope I can get there someday

Halcyon2024

that's industrial grade type of equipment. This is no longer a hobby for you is it? haha

Nope, it is an hobby, but you know, I'm in the metalworking industry since last century, I can't make bad parts fo me...

1

Davide->PreciousPlasticRomagna

Nope, it is an hobby, but you know, I'm in the metalworking industry since last century, I can't make bad parts fo me...

hahaha nice perks

1

We’ve had some trouble releasing the finished products from molds, like a vase and some glasses that we have (I can attach photos if it helps. We’ve read about some mold release sprays, has anyone used them and/or recommend them? Also, are there any DIY alternatives to the spray while we find it?

Alberto

We’ve had some trouble releasing the finished products from molds, like a vase and some glasses that we have (I can attach photos if it helps. We’ve read about some mold release sprays, has anyone used them and/or recommend them? Also, are there any DIY alternatives to the spray while we find it?

silicone oil or silicone release spray is what I commonly found being used in tutorial videos

8:20 PM

also apply to the mould before the process

Alberto

We’ve had some trouble releasing the finished products from molds, like a vase and some glasses that we have (I can attach photos if it helps. We’ve read about some mold release sprays, has anyone used them and/or recommend them? Also, are there any DIY alternatives to the spray while we find it?

Share photos! There's some different sprays but there's also a non-aerosol sold in jugs you can use but it depends on if you can find it where you are located. Silicone mould release works. Silicone oil has different viscosities so be sure to use the thinnest one, otherwise you'll have a mess on your hands.

2:36 AM

1

2:36 AM

Here's what I use. I should put it in a spray bottle so I stop using too much

ordinary oil will work as a mold release too. I had a South African engineer tell me they used that instead of silicone.

2:37 AM

i have used palm cooking oil as a release

I've had discoloration and build up issues with cooking oil when using sheet press, but it's really hard to beat that price.

mineral oil has a higher polymerization temp

Ben - Precious Plastic Ciledug

Click to see attachment 🖼️

is it available on tokopedia?

Halcyon2024

is it available on tokopedia?

https://www.tokopedia.com/atlanticchemical/ups-f-301-silicone-mould-release-silicone-mold-literan-1-liter

Ben - Precious Plastic Ciledug

https://www.tokopedia.com/atlanticchemical/ups-f-301-silicone-mould-release-silicone-mold-literan-1-liter

thank you my good sir

1

Davide->PreciousPlasticRomagna

Second one. Just another hexagon tile mold, but I made some modifications. I read that someone had problems keep the tiles sticking on the wall, so I decided to try to add some little spacers on the side. They are 2.5mm thick and they protrude from the sides 4mm. I made them to help to keep the distance between the tiles during installation, and they also lock the tiles when incorporated in the grout, no matter if it is made with resins (I'm wondering using black poliurethane sealant to glue them on the wall) or adhesives or probably also the normal tile grout.

Hey, this mould be be possible to make with laser cut, and you could save tons of money. Laser cut mould would need to be from 4x parts. Of course you would lose rounded corners, but its perfect for experiments, or even small production

1

Martin PP Slovakia

Hey, this mould be be possible to make with laser cut, and you could save tons of money. Laser cut mould would need to be from 4x parts. Of course you would lose rounded corners, but its perfect for experiments, or even small production

I know. But I'm a lathe machinist on a CNC one with live tooling, I made the parts for free (for the tile mold I made it from scrap material)!

1

Davide->PreciousPlasticRomagna

I know. But I'm a lathe machinist on a CNC one with live tooling, I made the parts for free (for the tile mold I made it from scrap material)!

lathe molds are cheap to make and sell compared to cnc 3 or 4 axis stuff.

A CNC lathe with live tooling isn't simply a lathe. How did you think I made the hexagon milling?

Hello haven’t been here in a while hope all of you are doing good … i’m here asking for some help wondering if anybody has built the brick mold I’m hoping to get the thickness of the material that is needed to create the mold

Hello I am looking for help with building the Lego mold brick that is used with the extruder my question is what thickness of metal Is used to construct the mold

@1plasticlife.org Hey, the thickness of the material is in the file name of each lasercut file?

1:31 AM

https://community.preciousplastic.com/how-to/brick-mould step 4 explains the naming structure of the files

Brick mould

Recycled plastic has the potential to replace more conventional and wasteful building materials such as hollow blocks. In this How-to, you will learn how to assemble the mould for the extruded plastic brick, ready for production. This brick was developed with the Extrusion Pro machine. Learn here how to build it:

What do people like for software for designing molds to be machined by CNC?

@JohnNephew I love Fusion360, but I also use FreeCAD. Other tools like Meshlab, TinkerCAD and Meshmixer have some interesting functions for workflow.

1

CitSciWorkshop

@JohnNephew I love Fusion360, but I also use FreeCAD. Other tools like Meshlab, TinkerCAD and Meshmixer have some interesting functions for workflow.

Hmm, seems like TinkerCAD might be best for a beginner looking to fiddle around?

JohnNephew

Hmm, seems like TinkerCAD might be best for a beginner looking to fiddle around?

It's great for sharing ideas, moves right up into other AutoCAD software and actually has some pretty powerful tools. (edited)

JohnNephew

What do people like for software for designing molds to be machined by CNC?

People use quite a few different programs for this. I think Fusion360 is quite popular but they had some fairly recent changes with licensing so it's quite expensive, in fact i think it's not feasible for any workspace who operates at precious plastic workspace level unless you manage to get a free educational account. Personally, i use sketchup. there's a free web version that's easy to use and i prefer it over TinkerCAD.

Ben - Precious Plastic Ciledug

People use quite a few different programs for this. I think Fusion360 is quite popular but they had some fairly recent changes with licensing so it's quite expensive, in fact i think it's not feasible for any workspace who operates at precious plastic workspace level unless you manage to get a free educational account. Personally, i use sketchup. there's a free web version that's easy to use and i prefer it over TinkerCAD.

Thanks!

CitSciWorkshop

@JohnNephew I love Fusion360, but I also use FreeCAD. Other tools like Meshlab, TinkerCAD and Meshmixer have some interesting functions for workflow.

I'm in search of a software who can allow me to make 3D parts, I started using Inventor years ago, but now I lost it (long story), I know that it is possible to use blender, but I have to learn all from scratch and I'm busy... I need to export 3D as .stl to make CAM programs at job...

Ben - Precious Plastic Ciledug

People use quite a few different programs for this. I think Fusion360 is quite popular but they had some fairly recent changes with licensing so it's quite expensive, in fact i think it's not feasible for any workspace who operates at precious plastic workspace level unless you manage to get a free educational account. Personally, i use sketchup. there's a free web version that's easy to use and i prefer it over TinkerCAD.

F360 is free for personal use, and you can also apply for a free startup license https://www.autodesk.com/products/fusion-360/startups

Davide->PreciousPlasticRomagna

I'm in search of a software who can allow me to make 3D parts, I started using Inventor years ago, but now I lost it (long story), I know that it is possible to use blender, but I have to learn all from scratch and I'm busy... I need to export 3D as .stl to make CAM programs at job...

FreeCAD has some good workflow with CAM, you just need to set it all up independently. It's a good way for folks who can and like to do that. Paid F360 carries a lot of good CAM workflow and popular machine profiles, I'm not sure where those features kick in but they do have a lot of sales for small business and I believe at least some of those features are in the entrepreneur license.

1

Hello! Very nice feedback around here

I am a furniture master student in Bergen, Norway... and currently doing some research about HDPE furniture. Do you know if there is somewhere I can get some medium large sheets of HDPE? Thanks in advance!

Helenemily

Hello! Very nice feedback around here

I am a furniture master student in Bergen, Norway... and currently doing some research about HDPE furniture. Do you know if there is somewhere I can get some medium large sheets of HDPE? Thanks in advance!

Did you look here ? https://bazar.preciousplastic.com/raw-material/sheets/ There is sellers in France, Austria and Netherland, I believe they can ship to Norway if you ask them.

Raw Material :: Sheets

Yann

Did you look here ? https://bazar.preciousplastic.com/raw-material/sheets/ There is sellers in France, Austria and Netherland, I believe they can ship to Norway if you ask them.

Oh wow, that's perfect! Thank you very much! :))

Davide->PreciousPlasticRomagna

Today I tested my injection machine. Seems working fine, I made some hexagonal test tiles with the mold I made this week. First one came out incomplete, others came out a lot better. Not the coolest colors since I had limited amount of shredded material, but enough to test it. I can't find any chart for right temperatures. I started with 180°C barrel and 200°C nozzle, and then I cranked up to 225°C barrel and 250°C nozzle. With higher temps seems working better. ~330bar inejction pressure. Any suggestion is highly appreciated. PS:I didn't try to make pots because I forget to take in account that barrel lenght increases with heating...I made the mold to slide precisely under the barrel, but with it in temperature they collide, it is matter of half a mm or less. Tomorrow or monday I give it a touch on the lathe to make it fit as needed...

Awesome stuff, I'm also testing my injection machine today and came in to check if there was any consensus on temperatures as all the documents and guides are not very specific.

iyD

Awesome stuff, I'm also testing my injection machine today and came in to check if there was any consensus on temperatures as all the documents and guides are not very specific.

I'm in the same condition. I can't find precise information around. I decided to perform some test, and for now I know that the HDPE I had for the testing, recycled blow molding one from jerrycans, not the best for injection, works well with my setup at 180°C barrel, 190°C nozzle. Tried at lower temperatures, 170/180, and the flow isn't good. At higher temperatures (200/230) with 300bar injection pressure I have too much thin flashing at the edge of the parts (something like 0.02mm in thickness, but annoying to clean out) and more shrinkage. Probably the right way is to adapt temperatures to the machine and mold, starting at lower temperature is better than starting too high. (edited)

3

Yesterday I made some plant pots trying to find the right temperatures and pressure. Seems that the main problem is related to the cooler temperatures on the injector tip, so there the plastic become thicker. Raising the nozzle temperature seems to solve the issue.

12:27 PM

12:29 PM

Seems that the missing part comes from a partially clogged passage to the hotter plastic behind.

12:29 PM

Some flashing with 550 bar injection pressure.

12:30 PM

2

12:31 PM

Good ones with 450bar and 230° nozzle/200° barrel temperature. First one made from bottle caps HDPE, the second is made with blow molding HDPE.

12:32 PM

Any suggestion to reduce the air trapped in the injector? There are some thin bubbles.

Davide->PreciousPlasticRomagna

Any suggestion to reduce the air trapped in the injector? There are some thin bubbles.

this can be due to different reasons, can be that

the mould is too cold
or plastic is not at the right temperature
not enough pressure and / or plastic For the bubbles you have to avoid plastics that might held some moisture and when feeding the material in the barrel make sure to compact it a bit every now and then while is melting. Also i have discovered that when the injection point is small (around 3-4 mm diameter) can help with the compaction too (and looks better too ) Last but not least, i highly recommend you to visit this how-to! https://community.preciousplastic.com/how-to/trouble-shooting-injection-moulding

(edited)

Carolina

this can be due to different reasons, can be that

the mould is too cold
or plastic is not at the right temperature
not enough pressure and / or plastic For the bubbles you have to avoid plastics that might held some moisture and when feeding the material in the barrel make sure to compact it a bit every now and then while is melting. Also i have discovered that when the injection point is small (around 3-4 mm diameter) can help with the compaction too (and looks better too ) Last but not least, i highly recommend you to visit this how-to! https://community.preciousplastic.com/how-to/trouble-shooting-injection-moulding

(edited)

Thanks for the reply! Mold was ~30/40°C and more after some injection, so it seems to be ok. As I wrote I tried raising temperatures up to 230° on the nozzle and 200° on the barrel, that seems to have solved the issue. Pressure isn't a problem I think, since I'm using a hydraulic press I can reach a theoretical pressure of 500bar in the plastic. However, It seems to me that my problem (in regard to the incomplete filling of the mold) was related to a "no too hot" injector tip, with the addition of using blow molding HDPE. The yellow one I have is very viscous, probably because it was part of very long and thin "telescopic boxes" (I don't know their name in english, the ones used for metalworking tools) and they needed a viscous plastic to fill the mold correctly. Seems not the best choice for injection

I used some in compression molding and it has a viscosity (at 180°C) that reminds me of those bad cheap chewing gum after half an hour of chewing...

However, seems that the correct temperature+a higher pressure have solved the problem. About bubbles, I definitely have to dry the plastic. It's related to an issue with the roof laboratory+some rain coming in. I let it to dry in an open cardboard box after shredding, but I haven't heating there, so it seems that at 4~8°C water isn't evaporating fast enough... Smaller nozzle diameter are ready for use, If drying doesn't help I go for them. Thanks to a lot! PS:What did you think about the finish of the good ones?

1

Davide->PreciousPlasticRomagna

Click to see attachment 🖼️

these look great

1

Davide->PreciousPlasticRomagna

I'm in the same condition. I can't find precise information around. I decided to perform some test, and for now I know that the HDPE I had for the testing, recycled blow molding one from jerrycans, not the best for injection, works well with my setup at 180°C barrel, 190°C nozzle. Tried at lower temperatures, 170/180, and the flow isn't good. At higher temperatures (200/230) with 300bar injection pressure I have too much thin flashing at the edge of the parts (something like 0.02mm in thickness, but annoying to clean out) and more shrinkage. Probably the right way is to adapt temperatures to the machine and mold, starting at lower temperature is better than starting too high. (edited)

Tested mine out at 275/295 after seeing another Community member's video on YouTube and it came out perfect. I don't have any insulation around my heating elements yet, so I may end up working at lower temperatures once that is setup. I do agree though that each machine has its own working temperature and its better to start low and raise in 5 or 10 degree increments as you test.

Hi friends - want to know from you all abt an easy way of mould release while making PS beams. Extrusion using PS is delightful but mould release is a pain and needs decent amount of hammering

iyD

Tested mine out at 275/295 after seeing another Community member's video on YouTube and it came out perfect. I don't have any insulation around my heating elements yet, so I may end up working at lower temperatures once that is setup. I do agree though that each machine has its own working temperature and its better to start low and raise in 5 or 10 degree increments as you test.

Very first coaster out of the machine...some black dots on it from residue built up in the barrel during machine manufacture...but apart from that plastic flow was fine and the material feel and final finish were also 100%

1

Priyank Mishra

Hi friends - want to know from you all abt an easy way of mould release while making PS beams. Extrusion using PS is delightful but mould release is a pain and needs decent amount of hammering

this is because PS barely shrinks, making it hard and sometimes impossible to demould (edited)

1

Carolina

this is because PS barely shrinks, making it hard and sometimes impossible to demould (edited)

Thanks Carolina. I agree. But is there some way (may be using WD-40 or something else) which makes it slightly easy? I have a retail store which donates a lot of broken PS hangers.

Priyank Mishra

Thanks Carolina. I agree. But is there some way (may be using WD-40 or something else) which makes it slightly easy? I have a retail store which donates a lot of broken PS hangers.

we use silicon oil as mould release, but i can't ensure it will work. Another thing that can help is to use extruded metal beams for mould, not the welded ones, so they are smoother on the inside

1

Carolina

we use silicon oil as mould release, but i can't ensure it will work. Another thing that can help is to use extruded metal beams for mould, not the welded ones, so they are smoother on the inside

Thanks. Let me try silicon oil for mould release. I have been trying out PS extrusion in steel moulds which are quite smooth on the inside.

1

Priyank Mishra

Thanks. Let me try silicon oil for mould release. I have been trying out PS extrusion in steel moulds which are quite smooth on the inside.

Also, try shorter beams, the longer the harder it gets to demould

1

iyD

Tested mine out at 275/295 after seeing another Community member's video on YouTube and it came out perfect. I don't have any insulation around my heating elements yet, so I may end up working at lower temperatures once that is setup. I do agree though that each machine has its own working temperature and its better to start low and raise in 5 or 10 degree increments as you test.

At higher temperatures than 240° mine starts to burn the plastic. Seems that I have a precise temperature reading, I put some heat conductive compound on the thermocouples, and my barrel is insulated with ceramic wool. I'm waiting to finish the HDPE shredding to clean the shredder and start with some polypropylene, that seems to flow a lot better.

1

Carolina

Also, try shorter beams, the longer the harder it gets to demould

just to confirm the exact process, silicon oil is put inside the mould before or after the extrusion? I ask this as I realise that using any oil at such temperatures tend to burn the oil leaving black marks on the beam.

Priyank Mishra

just to confirm the exact process, silicon oil is put inside the mould before or after the extrusion? I ask this as I realise that using any oil at such temperatures tend to burn the oil leaving black marks on the beam.

Before, same way you would do when baking a cake

We use silicon oil exactly because it resists super high temperatures

Priyank Mishra

Hi friends - want to know from you all abt an easy way of mould release while making PS beams. Extrusion using PS is delightful but mould release is a pain and needs decent amount of hammering

i have a solution but like always... it costs money and time. I had some pretty bad struggles with some moulds getting stuck. If i extruded into a square hollow tube/pipe and had the end of the pipe closed off, the pressure would cause the pipe to deform and the plastic would end up getting stuck inside. My solution to this was to make a mould that has one side that can be unblolted. So for example, if im making a plank that's 150cm x 10cm x 2cm, i would have a cover on a side that covers the dimension 150cm x 10cm. This allows access to the plastic from many different and you wont struggle with demoulding....however.....you will spend more time taking apart the mould and putting it back together....but at least you can get it out

1

2:55 AM

here's an example of the mould... this extrusion was a failure but you can get an idea of how the mould is put together

Does anyone ever put a block of wood in front of the extrusion mold to build backpressure right away or something to provide initial resistance to build the plug? Seems like extruding continuous from an open ended mold should work?

waterppk

Does anyone ever put a block of wood in front of the extrusion mold to build backpressure right away or something to provide initial resistance to build the plug? Seems like extruding continuous from an open ended mold should work?

https://youtu.be/bZKtfT6y0v8?t=169

Brothers Make

We made a PALLET out of 100% Recycled DVD Cases

11:59 AM

Does anyone have a few PreciousPlastic-Coins to sell? PP don´t have them anymore and I need them for a mould design.

what's a PP coin? Like these ones? https://bazar.preciousplastic.com/products/other/stamps-coin/

Products :: Other :: Stamps Coin

Thomas Peterberns | Johannplasto

https://youtu.be/bZKtfT6y0v8?t=169

Interesting, I was thinking ram it down the mold at the beginning so the plastic has something to push against as it's extruded, might help to build more pressure/smoother walls

waterppk

what's a PP coin? Like these ones? https://bazar.preciousplastic.com/products/other/stamps-coin/

Yes, but that one you linked is not the original one. And I need the original dimensions.

Davide->PreciousPlasticRomagna

At higher temperatures than 240° mine starts to burn the plastic. Seems that I have a precise temperature reading, I put some heat conductive compound on the thermocouples, and my barrel is insulated with ceramic wool. I'm waiting to finish the HDPE shredding to clean the shredder and start with some polypropylene, that seems to flow a lot better.

I've been working only with PP from my kitchen waste as pretty much all food items come in PP. Now I have a doubt. Has anyone worked with plastic that has imprints on its surface like the image attached? Does the ink affect the moulding process in any way, is it safe to use? So far I have only worked with containers that have no imprint on them.

https://forms.gle/jsLC1jXFkyCGsvoy7 Hi guys please take a minute or two to help me out with a quick survey for some details on the product I am working on. Thank you

iyD Recycled Coasters

iyD is a product design studio with a focus on creating simple and functional items that pose little to no harm to the environment. With that in mind we are developing coasters made from 100% recycled plastic. We also want the packaging for the coasters to be minimalistic, easily degradable and efficient to produce. Shown in the images below ar...

Hello guys!! Does anyone know if it is possible to make a injection mold using the lost wax casting process? Would be amazing if anyone knew and it feels like it could be good for small details and maybe cheaper

10:07 PM

https://youtu.be/Q-0fdOmKb48

DMA.Studio

Hulk Metal Casting - Lost Wax Casting Process - Casting Aluminium

10:07 PM

Using the same process as this ⬆️

ViggoSjoberg

Hello guys!! Does anyone know if it is possible to make a injection mold using the lost wax casting process? Would be amazing if anyone knew and it feels like it could be good for small details and maybe cheaper

I'd sure be interested in how to do such a thing

ViggoSjoberg

Hello guys!! Does anyone know if it is possible to make a injection mold using the lost wax casting process? Would be amazing if anyone knew and it feels like it could be good for small details and maybe cheaper

It's doable of course. I don't think anyone will argue against doing this. It's just I don't think anyone here goes that far with casting metal. It's been on my mind for years, but I always end up doing other things. I'd say, do it and tell us how it goes. Be careful for spatters. There's a ton of these videos online and it drives me nuts how easy it looks.

Just gotta share this somewhere. I struggled a bit figuring out these moulds and had to deal with welds breaking (not welded good enough) and some struggle with using the right tools for opening and closing the moulds and also connecting to my machine as the connection is a little different than what others use. I extruded 100% HDPE, full speed with my extrusion pro and I think single and double has so far 100% success rate, I just did the triple and it looks usable, not fully filled out for the top but I think good enough. Product weights: Single - 710g Double - 1200g Triple - 1700g

3

10:35 AM

Power tools for the win

Ben - Precious Plastic Ciledug

Just gotta share this somewhere. I struggled a bit figuring out these moulds and had to deal with welds breaking (not welded good enough) and some struggle with using the right tools for opening and closing the moulds and also connecting to my machine as the connection is a little different than what others use. I extruded 100% HDPE, full speed with my extrusion pro and I think single and double has so far 100% success rate, I just did the triple and it looks usable, not fully filled out for the top but I think good enough. Product weights: Single - 710g Double - 1200g Triple - 1700g

Very good job!

Ben - Precious Plastic Ciledug

Power tools for the win

you made that 100% plastic? would you think its a good idea to make that with a mixture of plastic and sand. kind of like a brick.

Rj

you made that 100% plastic? would you think its a good idea to make that with a mixture of plastic and sand. kind of like a brick.

It’s best to keep the product pure and not mix it with anything other plastics or other materials

Rj

you made that 100% plastic? would you think its a good idea to make that with a mixture of plastic and sand. kind of like a brick.

There's a few reasons why you shouldn't. 1. It wears the machine down faster. 2. Makes it incredibly more difficult to recycle again at a later date. 3. It makes the product more heavy (when you consider the proper way to install these, weight plays no real role) but might increase shipping costs. 4. Sand mining isnt really a good thing, better to just not mix it in. Why would you mix in other material? To keep costs down? If the goal is to keep costs down then you have whatever local methods for building structures that might be more affordable. We don't always recycle because it's cheaper, but mostly because we are trying to help mitigate a larger problem. I hope this clears up a little bit for you @Rj ,its a good question and needs to be asked and discussed from time to time. I'm sure there are others with different opinions on the matter. I'm not going to say one way is right and another is wrong, there's so many things to consider when doing this work.

6:05 AM

Oh, ya so these are 100% HDPE plastic.

Hi all! I am from Barcelona and we are trying to contact a company to do a specific mold for our injection. It is a little hard to find someone to do it, any ideas? Thanks!

Hi @Raul Andromines, you can shoot me a PM and I can check if I can help you

Just got this delivered today. If you know of a place that does (fiber) laser cutting, it can be quite affordable. Only rp650.000 or ~40eur/usd for this in Indonesia. I need to drill out a hole for the injection nozzle, they said the hoke was too small for 10mm steel plate...not a big deal for me.

4

Are there any designs available for a pot mould cut from sheet metal plates? I have a CNC plasma cutter, I'd like to cut up some steel and weld it together to make a panel pot mould

This looks helpful: https://community.preciousplastic.com/how-to/create-a-bowl-using-a-laser-cut-mould I'll work from that

Create a bowl using a laser cut mould

Mathijs will show you how to create an iconic recycled bowl using a lasercut moud.

Some other color testing for the small plant pot mold.

5

6

Plasma cut 10 gauge steel and got it halfway welded tonight

3

2

1

3:10 AM

made a lot more sense to polish it before assembling the pieces to minimize internal cleanup work

5

3

need to polish the welds on the interior mould (the plastic shrinks so it grips the center and easily releases from the exterior) otherwise it worked great. Also need to figure out how much material fills it completely

4:43 AM

Put it in a lab convection oven at 160C *and used a regular 20 ton hydraulic press to lightly* squish it until the to and bottom of the mould made contact

1

waterppk

Click to see attachment 🖼️

The last image with the plastic lit up looks really pretty

Looks awesome!

1

2

1

7:06 PM

PLA scraps from a multi material changer on a Bambu printer (Prusa makes the same type of scrap). Ran around 210*C for 60 minutes to melt, then lightly pressed, and rapidly cooled with a leaf blower while under pressure (edited)

GamingFedora

The last image with the plastic lit up looks really pretty

We're going to try mixing bowls to make a thin shade for a lamp

Nice!

Still learning but made this state of Tennessee fridge magnet from #2 hdpe (edited)

2

1

ho4dli5

Still learning but made this state of Tennessee fridge magnet from #2 hdpe (edited)

Using a cookie cutter?

Ben - Precious Plastic Ciledug

Using a cookie cutter?

Yes. I’m just getting started and will build molds soon (edited)

ho4dli5

Yes. I’m just getting started and will build molds soon (edited)

Looks good though! I like how i know exactly what it is by looking at it.

Looking for a fishing hook mould to make product like this. Anyone knows where to get it? Does anyone here makes custom moulds? Thx

marjanzitnik

Looking for a fishing hook mould to make product like this. Anyone knows where to get it? Does anyone here makes custom moulds? Thx

I hope the hook on that is dull, or solely cosmetic.

I would like to know as well!

marjanzitnik

Looking for a fishing hook mould to make product like this. Anyone knows where to get it? Does anyone here makes custom moulds? Thx

@Fritz @easymoulds Is one mouldmaker on the Channel i know

I have a mould maker in Indonesia but you won't like the shipping fees.

Rj

you made that 100% plastic? would you think its a good idea to make that with a mixture of plastic and sand. kind of like a brick.

no, no, no, no no. Respectfully.

Ben - Precious Plastic Ciledug

Just gotta share this somewhere. I struggled a bit figuring out these moulds and had to deal with welds breaking (not welded good enough) and some struggle with using the right tools for opening and closing the moulds and also connecting to my machine as the connection is a little different than what others use. I extruded 100% HDPE, full speed with my extrusion pro and I think single and double has so far 100% success rate, I just did the triple and it looks usable, not fully filled out for the top but I think good enough. Product weights: Single - 710g Double - 1200g Triple - 1700g

Ben, that's awesome. I am just finishing the brick moulds for our gig. Getting very close to extruding.

Geoff (PBI NTB)

Ben, that's awesome. I am just finishing the brick moulds for our gig. Getting very close to extruding.

Very nice Geoff! I've been taking it easy for my first order of 90 bricks using Aqua bottlecaps. It flows fairly well and doesn't have as much resistance as PP usually has. If you have an impact wrench it helps save a bunch of time for putting on and taking off the bolts. Some prybars are helpful too.

Ben - Precious Plastic Ciledug

Very nice Geoff! I've been taking it easy for my first order of 90 bricks using Aqua bottlecaps. It flows fairly well and doesn't have as much resistance as PP usually has. If you have an impact wrench it helps save a bunch of time for putting on and taking off the bolts. Some prybars are helpful too.

Yeah i just welded the nuts to the top of the triple and questioned why two nuts 20mm apart on top and bottom plate of the top piece? If the threads are not exactly aligned you would not be able to get the bolt to turn into the second nut....???

Ben - Precious Plastic Ciledug

Very nice Geoff! I've been taking it easy for my first order of 90 bricks using Aqua bottlecaps. It flows fairly well and doesn't have as much resistance as PP usually has. If you have an impact wrench it helps save a bunch of time for putting on and taking off the bolts. Some prybars are helpful too.

I also noticed in the short brick video, they dont use the bolts but instead hammer a rod through to remove the brick.

Geoff (PBI NTB)

Yeah i just welded the nuts to the top of the triple and questioned why two nuts 20mm apart on top and bottom plate of the top piece? If the threads are not exactly aligned you would not be able to get the bolt to turn into the second nut....???

The mould I have has 4 bolts on the bottom and 6 bolts for the top. The 6 bolt side doesn't need to be taken apart for removing the brick, the 4 bolt side does. I have been using a vice grip right in the middle for peace of mind

9:41 AM

My moulds did not follow the blueprints so i have my own struggles

Ben - Precious Plastic Ciledug

My moulds did not follow the blueprints so i have my own struggles

Ah okay.

Geoff (PBI NTB)

Yeah i just welded the nuts to the top of the triple and questioned why two nuts 20mm apart on top and bottom plate of the top piece? If the threads are not exactly aligned you would not be able to get the bolt to turn into the second nut....???

Oh! The two nuts on the top are for helping separate the moulds. I don't have that....fortunately things pry apart well enough

9:43 AM

you run a bolt through them after you've taken off the bottom nuts and it should come out. prying off the male part of the mould is a piece of cake if you have two pry bars...if you dont, you better get some

Ben - Precious Plastic Ciledug

There's a few reasons why you shouldn't. 1. It wears the machine down faster. 2. Makes it incredibly more difficult to recycle again at a later date. 3. It makes the product more heavy (when you consider the proper way to install these, weight plays no real role) but might increase shipping costs. 4. Sand mining isnt really a good thing, better to just not mix it in. Why would you mix in other material? To keep costs down? If the goal is to keep costs down then you have whatever local methods for building structures that might be more affordable. We don't always recycle because it's cheaper, but mostly because we are trying to help mitigate a larger problem. I hope this clears up a little bit for you @Rj ,its a good question and needs to be asked and discussed from time to time. I'm sure there are others with different opinions on the matter. I'm not going to say one way is right and another is wrong, there's so many things to consider when doing this work.

hey, thanks for the advice, thats why i'm here, i'm new to this, i love this thing you started. i'm a teacher and i want to start something like this with my students, collecting plastic from their homes, and from within their own little worlds, and teaching them about recycling, and cleaning up this wonderful planet; and how to use it to make something, like bricks. the reason why i asked, i saw a youtube video of someone in Africa (i think) making bricks like that, sand and plastic (or maybe i just miss-understood and got it all wrong) but i know your the experts, and i'm glade and thankful you're here for me to ask questions like this. again thank you, i think you just saved me from doing something stupid. (edited)

Rj

hey, thanks for the advice, thats why i'm here, i'm new to this, i love this thing you started. i'm a teacher and i want to start something like this with my students, collecting plastic from their homes, and from within their own little worlds, and teaching them about recycling, and cleaning up this wonderful planet; and how to use it to make something, like bricks. the reason why i asked, i saw a youtube video of someone in Africa (i think) making bricks like that, sand and plastic (or maybe i just miss-understood and got it all wrong) but i know your the experts, and i'm glade and thankful you're here for me to ask questions like this. again thank you, i think you just saved me from doing something stupid. (edited)

That's awesome Rj. Good on ya. Yes I have seen a few of those videos of just raw bricks and sand, asphalt repairs and so-on. The question Ben addressed well is what to do with it when someone decides it needs to be replaced. Then where does it go. It's no longer a circular resource because of the contamination.

Geoff (PBI NTB)

That's awesome Rj. Good on ya. Yes I have seen a few of those videos of just raw bricks and sand, asphalt repairs and so-on. The question Ben addressed well is what to do with it when someone decides it needs to be replaced. Then where does it go. It's no longer a circular resource because of the contamination.

hey, you make a very good point, thanks. and also what happens with the bricks that don't turn out?

If you are optimistic and say everything is recyclable, i hope you have deep pockets. There's a reason why not everything gets recycled and why we have so much garbage in landfills.

Rj

hey, you make a very good point, thanks. and also what happens with the bricks that don't turn out?

If they are 100% one type of plastic, reshred and reprint. If they are mixed with contaminants, I guess Pyrolisis for Diesel.

Rj

hey, you make a very good point, thanks. and also what happens with the bricks that don't turn out?

I just had this issue. I was running out of material so i had to cut down and reshred some of my rejects from my first attempts.

The same goes for simple injection projects too. You make small things and they fail for whatever reason, you just toss it in the shredder and try again. There is a limit to this process but if you have enough material around, it's not likely you will have much problems.

Ben - Precious Plastic Ciledug

I just had this issue. I was running out of material so i had to cut down and reshred some of my rejects from my first attempts.

The same goes for simple injection projects too. You make small things and they fail for whatever reason, you just toss it in the shredder and try again. There is a limit to this process but if you have enough material around, it's not likely you will have much problems.

so say HDPE has its limits to how often you can re-shred and re-from? (edited)

Rj

so say HDPE has its limits to how often you can re-shred and re-from? (edited)

I've read people saying all sorts of different things about how many times a single piece of plastic can be recycled, but realistically the material will become more brittle and basically no longer be plastic. In the recycling industry, it is common for there to be a blend of virgin plastic with recycled plastic to get a better quality product.

10:03 AM

Here's my 90 bricks for you @Geoff (PBI NTB)

Rj

so say HDPE has its limits to how often you can re-shred and re-from? (edited)

Im no chemistry teacher, and as such I think the Chain Smokers start to break down and go their separate ways, essentially they stop making music together.

Ben - Precious Plastic Ciledug

Here's my 90 bricks for you @Geoff (PBI NTB)

They are gorgeous looking bricks mate.

Ben - Precious Plastic Ciledug

Here's my 90 bricks for you @Geoff (PBI NTB)

OH WOW those are some beautiful looking bricks. bud.

Geoff (PBI NTB)

Im no chemistry teacher, and as such I think the Chain Smokers start to break down and go their separate ways, essentially they stop making music together.

hahaha, i'm no Chemistry Teacher ether (i teach math) but i think i get what your referring to hahaha

Maybe i'll stack them really quick....

Ben - Precious Plastic Ciledug

Maybe i'll stack them really quick....

Awesome tie-die t-shirt renaissance going on there.

1

10:26 AM

Here you go @Geoff (PBI NTB) ✌️

️

1

Ben - Precious Plastic Ciledug

Very nice Geoff! I've been taking it easy for my first order of 90 bricks using Aqua bottlecaps. It flows fairly well and doesn't have as much resistance as PP usually has. If you have an impact wrench it helps save a bunch of time for putting on and taking off the bolts. Some prybars are helpful too.

BTW, how much do you sell a brick for?

Triple - Rp50.000 Double - Rp40.000 Single - Rp30.000

3

6:08 PM

2 stainless steel mixing bowls (different sizes are needed, you can't use two of the same size or the bottom will get very thick relative to the walls) work very well as a compression mould. We filled the bottom with flake, put it in the convection oven, then squeezed with a hydraulic press (lightly) until it pushed up the walls

6:08 PM

this was HDPE, made a very cool lampshade

Cool!

waterppk

Click to see attachment 🖼️

Very Nice

Anyone suceeded to make a hollow beam (beam with hole inside) with extruder machine?

waterppk

Click to see attachment 🖼️

Cool work! Not sure if you want/need any inspiration but these guys have been using the same process for a while now. They mix it up with some weaving too. https://instagram.com/plastikkembali

Ben - Precious Plastic Ciledug

Cool work! Not sure if you want/need any inspiration but these guys have been using the same process for a while now. They mix it up with some weaving too. https://instagram.com/plastikkembali

I'll take a look, I'm basically the machine builder/maintainer we have some folks here interested in working out a commercialization model of some sort

There's some really cool things you can do with this simple bowl press method. Although i must admit, i have ruined a few bowls myself.

Hey there! I've been interested in this project for a couple of years now but only recently got the urge to involve myself and I have a question about Injection Molding: What are the limits with Injection Molding recycled plastics? Think thickness and fidelity, quality and reliability?

blablagame

Hey there! I've been interested in this project for a couple of years now but only recently got the urge to involve myself and I have a question about Injection Molding: What are the limits with Injection Molding recycled plastics? Think thickness and fidelity, quality and reliability?

Not easy questions as the answers will vary from machine to machine. Some people struggle with injection, some people have their machines sorted out. Better molds make better products. Higher pressure has better results. Human provided power is not always reliable.

1

Thanks for sharing your experience! There's a foundation point near me on the map but they haven't responded to my email yet, I'll have to see how far they've come

10:06 AM

Acid etching the caribiner mould with some writing. I'm hoping my results actually show something!

Will find out in 10 minutes

Acid etching wasn't deep enough. Not really surprised, but mostly the issue is that the cold steel causes the plastic to wrinkle. I'm gonna toss the mould in the oven for 25 minutes and see what we get.

10:22 AM

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11:22 AM

If you want to do acid etching, it's doable for injection moulding with a condition that you either must preheat your mould or use a lot of pressure. The problem with preheating the mould is that it fills up the mould too well. It will flow everywhere in your mould and make for a miserable time cleaning things up

11:22 AM

Not a fun cleanup. Injection should be clean and simple.

1

Nice work. Another method to learn on the list

For hearing, A heat gun may work better

just heat the target area and u may solve the issue.

Oh, I was informed by a friend that using PP might yield better results... I hope someone buys these carabiners. Haha!

what material did you use?!

OK after some consideration, I figure acid etching might be better for textures than doing text and fine details. You can only go so deep without losing clarity. So for orders that have custom text or graphics, I'll use PP and my laser machine.

1

7:54 AM

Here's my template. I didn't spend too much time on it

1

7:55 AM

They look neat in plywood but are rather useless in this form as they break at the joint. (no surprises there)

Hello PP community, I am new to Discord and hope to ask the right channel. I want to start a PP operation here on the island of St. Martin (in the Caribbean) and create a sustainable business that does not rely on external funding or heavily touristy/artsy products. The goal: I want to focus on one production technology first, master that, and build upon the latest know-how from the community. The problem: not sure what is the best product-market-fit today on this island. References: There are success stories in the Carribean (https://www.limpirecycling.com/, https://greenphenix.com/, https://www.plasticbeachparty.com/) all following different business models and revenue streams and already experienced with different production technologies) My current equipment: PP Shredder v.1, few molds, panini press, wooden frame, shredded plastic flakes, saw, grinder etc (bought everything 2nd hand on the island) The building brick concept is super intriguing, given the island is hit by hurricanes and encourages a circular economy. Do you know if a use case exists here or is still experimental? What would be the best way to move forward given this context? *Additional PP equipment can be sourced from the bazaar for example - sea freight is affordable and there is no incoming goods tax on the island. * But what method to start with to get the "hands dirty" so to say... It is bootstrapped by me. Thank you all!

veggie

Hello PP community, I am new to Discord and hope to ask the right channel. I want to start a PP operation here on the island of St. Martin (in the Caribbean) and create a sustainable business that does not rely on external funding or heavily touristy/artsy products. The goal: I want to focus on one production technology first, master that, and build upon the latest know-how from the community. The problem: not sure what is the best product-market-fit today on this island. References: There are success stories in the Carribean (https://www.limpirecycling.com/, https://greenphenix.com/, https://www.plasticbeachparty.com/) all following different business models and revenue streams and already experienced with different production technologies) My current equipment: PP Shredder v.1, few molds, panini press, wooden frame, shredded plastic flakes, saw, grinder etc (bought everything 2nd hand on the island) The building brick concept is super intriguing, given the island is hit by hurricanes and encourages a circular economy. Do you know if a use case exists here or is still experimental? What would be the best way to move forward given this context? *Additional PP equipment can be sourced from the bazaar for example - sea freight is affordable and there is no incoming goods tax on the island. * But what method to start with to get the "hands dirty" so to say... It is bootstrapped by me. Thank you all!

Welcome! I think you need to figure out who your target market is. If it's not the artsy and touristy products, simple things like coasters sell fairly well. Injection moulding is good for repeatable success without a bunch of extra sanding and finishing. I haven't seen a use case yet for the bricks but, I might build a house next year with the Bricks. There is a minor problem with the Bricks, it's the amount of time needed to produce them. Depending on the building size, you might need to spend 8-9 months making the Bricks. This can get quite expensive depending on labor rates, unless you're a slave to your work and don't pay yourself. I've posted times previously for how long each brick takes me to make (excluding cooling and demoulding times), but to run your own calculations: Single - 4 minutes Double - 8 minutes Triple - 12 minutes If you use these times, add a few minutes for removing and installation of the moulds. To help improve production rates, I suggest having three of the triple moulds and one of the others. Use a cooling tank to put the moulds in to help them cool down quicker. I hope some of this info helps you!

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Ben - Precious Plastic Ciledug

Welcome! I think you need to figure out who your target market is. If it's not the artsy and touristy products, simple things like coasters sell fairly well. Injection moulding is good for repeatable success without a bunch of extra sanding and finishing. I haven't seen a use case yet for the bricks but, I might build a house next year with the Bricks. There is a minor problem with the Bricks, it's the amount of time needed to produce them. Depending on the building size, you might need to spend 8-9 months making the Bricks. This can get quite expensive depending on labor rates, unless you're a slave to your work and don't pay yourself. I've posted times previously for how long each brick takes me to make (excluding cooling and demoulding times), but to run your own calculations: Single - 4 minutes Double - 8 minutes Triple - 12 minutes If you use these times, add a few minutes for removing and installation of the moulds. To help improve production rates, I suggest having three of the triple moulds and one of the others. Use a cooling tank to put the moulds in to help them cool down quicker. I hope some of this info helps you!

Thank you for the great insight Ben! Do your 8 months of production time per building already take into account working with several molds or a single one in sequence? How many could 1 person (or is it significantly easier with 2 people?) create if working parallel on different molds per day? I am trying to estimate if the cost per brick is competitive with the one from the local hardware store. I can see this application for locals to repair damaged housing or extend their existing house. In any case, there should be an incentive for them to use it over the traditional brick. What type of plastic is your base material? I see there are different variations and people like to mix it with non-plastic particles to improve physical properties, etc. Can you use the same base material for outside furniture? Like stools, tables, etc.

veggie

Thank you for the great insight Ben! Do your 8 months of production time per building already take into account working with several molds or a single one in sequence? How many could 1 person (or is it significantly easier with 2 people?) create if working parallel on different molds per day? I am trying to estimate if the cost per brick is competitive with the one from the local hardware store. I can see this application for locals to repair damaged housing or extend their existing house. In any case, there should be an incentive for them to use it over the traditional brick. What type of plastic is your base material? I see there are different variations and people like to mix it with non-plastic particles to improve physical properties, etc. Can you use the same base material for outside furniture? Like stools, tables, etc.

I've tried to make as many bricks as possible in one day with one of each size mould. Because of the wait time for cooling down the bricks after they've extruded, you'll spend a lot of time waiting if you need to make just one type of brick. Triple sized brick needs around 5-8 minutes to cool down in a water bath plus enough time for demoulding. I've had some struggle getting these things apart but mostly have it down now. Using a cordless impact wrench helps significantly, just keep extra hardware around because it's likely you'll wear out the threads after a while (keep the threads lubed for longer lasting life). With two workers, you have one person managing the extrusion machine. They are in charge of getting the materials ready and making sure plastic flakes are flowing into the extrusion machine. The other person is in charge of moving the filled moulds for cooling, demoulding, and reassembling the mould. The one managing the machine can connect the mould and then run the machine. If you're doing it yourself, you'll be spending about half the time not running the machine and more focusing on moving the filled mould for cooling, demoulding, and getting your plastic ready. If you have no issues with your plastic feeding into the machine, then you might be able to shave off some of that time, but i always have some issues with plastic flake needing to be poked down, otherwise it basically makes it's own little cave and the plastic doesn't feed into the machine....there is a fix for this, you need something to agitate it but i haven't gotten around to doing this yet.

Your cost per bricks will vary quite a bit. But let's say you can produce 20 triple bricks per day. That's about 35kg of plastic. How much does your material cost? How much does your labor cost? How much does your overhead cost? How much do you set aside for machine depreciation?

These numbers vary wildly in the world. So far I've only used HDPE to inject the moulds with. I will try using PP eventually. I'm not a fan of mixing in stuff that is not plastic. I've mixed in all sorts of stuff... coffee grinds, sawdust, coconut fibers, sand...i don't recommend it for several reasons. Mostly, they just tend to cause problems with extruding whatever product you're trying to make. If you mix in less than 10% of other-than-plastic material. 25% or so tends to have more failures. HDPE and PP can be used outside but it's always recommended to keep these things covered as they tend to decay due to the sun. You can paint or cover up the plastic and it'll be fine.

Ben - Precious Plastic Ciledug

Your cost per bricks will vary quite a bit. But let's say you can produce 20 triple bricks per day. That's about 35kg of plastic. How much does your material cost? How much does your labor cost? How much does your overhead cost? How much do you set aside for machine depreciation?

These numbers vary wildly in the world. So far I've only used HDPE to inject the moulds with. I will try using PP eventually. I'm not a fan of mixing in stuff that is not plastic. I've mixed in all sorts of stuff... coffee grinds, sawdust, coconut fibers, sand...i don't recommend it for several reasons. Mostly, they just tend to cause problems with extruding whatever product you're trying to make. If you mix in less than 10% of other-than-plastic material. 25% or so tends to have more failures. HDPE and PP can be used outside but it's always recommended to keep these things covered as they tend to decay due to the sun. You can paint or cover up the plastic and it'll be fine.

That is very valuable information on the production and technical side and I can implement that into my context to analyze it. I definitely consider hiring a person for this - as my time is limited with my full-time job (which pays my bills, rent and also finances this project

) My approach is to have a use case first and then buy the required machine.

1

What is the best material to build outside furniture: like stools, beach tables, benches, trash bin housings? The guys in the Philippines seem already advanced in this game! I can see doing either sheets as a base material or these 'lumber' pieces as a great base material to be processed further.

Ben - Precious Plastic Ciledug

Here's my template. I didn't spend too much time on it

this is so simple but super smart! any tips on the parameters of the laser to not melt too much?

veggie

What is the best material to build outside furniture: like stools, beach tables, benches, trash bin housings? The guys in the Philippines seem already advanced in this game! I can see doing either sheets as a base material or these 'lumber' pieces as a great base material to be processed further.

Honestly, I don't know what the best material is but, there's things you can do that can help. If the plastic is exposed to UV rays, it will breakdown and lose color. If you add 3% of plastic weight with iron oxide pigment, the color will remain to a degree, you'll likely lose all the color of the original plastic but the iron oxide pigment will remain. There's two additives you can mix in to help manage UV damage. Titanium Dioxide (white) or Carbon Black. The first one helps reflect away UV rays and the latter will absorb UV rays into itself. These are not uncommon chemicals as one is used for food, cosmetics, deodorant, and the other is what makes tires black. Of course these will change the color of your material, but will help reduce the effect UV rays have

3

Carolina

this is so simple but super smart! any tips on the parameters of the laser to not melt too much?

There are limitations. If you're trying to do a large image, it won't work out very well. For example, someone asked me to try on a coaster. (PP doesn't work well for making coasters without pressing the material)

12:09 AM

However, for small parts or text, it comes out almost like it was embossed.

Carolina

this is so simple but super smart! any tips on the parameters of the laser to not melt too much?

Laser Settings for Small text like the carabiners above: Product Material: PP Machine: 100w CO2 laser Speed: 200mm/sec Power: 30% (30w) Line Interval: 0.1mm Mode: Fill Air Assist: on Note: HDPE doesn't really work for this or I just havent found the right setting yet. Ah, i should just make a How-To for this, huh?

1

A couple of interesting mould patterns/implementations: https://www.youtube.com/watch?v=kB-_BBMCq1g

Insider Business

How To Make Bricks From Plastic Trash | World Wide Waste | Insider ...

1

@Ben - Precious Plastic Ciledug Did you just engrave or also try to cut plastic sheets with laser? We are also trying around a little bit.

9:07 AM

In general I can say that a CO² laser is surely a better choice than a UV laser for this. But so far I only worked with a 60W laser. When cutting we usually don't have sharp but rather slightly molten edges (so far we mainly cut through PLA and HDPE). I think a 100W laser might produce better edges than a 60W laser, but I couldn't verify this yet

DataWorm (PP Berlin)

In general I can say that a CO² laser is surely a better choice than a UV laser for this. But so far I only worked with a 60W laser. When cutting we usually don't have sharp but rather slightly molten edges (so far we mainly cut through PLA and HDPE). I think a 100W laser might produce better edges than a 60W laser, but I couldn't verify this yet

Yes.

I've tried it all with HDPE and PP. Can cut HDPE and PP up to 1cm with 100w but you gotta watch for fires. Engraving HDPE is a fail. Engraving PP with some success. Same issues for cutting HDPE, it sort of melts and gets waxy/crusty. Cutting always puts out a big cloud of bad smoke so I suggest not doing it if you don't have to haha

Acrylic mould? Yep. Custom button order, I have no clue how many uses this will have but so far so good. Mould material: Top- steel 10mm Middle- acrylic 2mm Bottom- steel 10mm I reused part of the caribiner design, so this might look familiar

11:06 AM

Just need to drill holes now

Ben - Precious Plastic Ciledug

Yes.

I've tried it all with HDPE and PP. Can cut HDPE and PP up to 1cm with 100w but you gotta watch for fires. Engraving HDPE is a fail. Engraving PP with some success. Same issues for cutting HDPE, it sort of melts and gets waxy/crusty. Cutting always puts out a big cloud of bad smoke so I suggest not doing it if you don't have to haha

I cut PP once, but it was some fire resistant PP. Maybe i can show a picture later when i get home. Yeah you are right, lasercutting creates quite a bit of smoke, but at least it can be filtered easily. But for simple shapes it can be a cheap solution to create prototypes or small amount of badge rather than having to build expensive moulds

12:12 PM

But acryl mould can be obviously also a cheap solution for small batches

The acrylic does melt a little after each use which causes some voids that the injected plastic fills. Still cleans up easy. This is after about 6 uses. The profiles for the product are likely expanding a little bit after each use. Too much pressure likely will wear out the acrylic faster but there's nothing I can do about it. Once this mould wears out ill try and make a new sheet with it, but I'll be managing my expectations with this.

1

Does anyone make injection molds for making blanks for further machining (such as pen turning and CNC milling)? Knowing that there is a market for recycled sheet goods, after watching a recent Brothers Make video where they had a pen blank injection mold I was thinking that maybe an injection mold is the way to go to more quickly produce blanks for pen turning, knife scales, and other things where the competition is thermoset epoxy pours.

4:42 PM

I'm going to work on making some things along these lines for our incoming larger injection machine -- seems simple enough for even my poor metal manipulation skills, as I should be able to get some pre-cut metal and drill/tap holes for machine screws or bolts.

1

Ben - Precious Plastic Ciledug

Just gotta share this somewhere. I struggled a bit figuring out these moulds and had to deal with welds breaking (not welded good enough) and some struggle with using the right tools for opening and closing the moulds and also connecting to my machine as the connection is a little different than what others use. I extruded 100% HDPE, full speed with my extrusion pro and I think single and double has so far 100% success rate, I just did the triple and it looks usable, not fully filled out for the top but I think good enough. Product weights: Single - 710g Double - 1200g Triple - 1700g

Hey Ben, do you know the dimensions of these bricks?

Geoff (PBI NTB)

Hey Ben, do you know the dimensions of these bricks?

Triple = 300L x 100W x 165H (excluding the teeth)? Double = 200L x1 00W x 165H (ditto) Single = 100L x 100W x 165H (edited)

Last week I tried to make an aluminium mold with the small DIY CNC mill we have in the laboratory. It's just a test with something useful, a keychain for a friends association. Seems working, after some issue with the CAM. It has to be squared to dimensions, i used two scrap aluminium piece, it's just a matter of clamping them together with pins in place and mill out the excess material (and to make the chamfer for the nozzle).

1

My project today: engraving this sheet of aluminum for a mold for terrain for games like Dungeons & Dragons, with 1" squares and a flagstone pattern.

4

3

1

5:17 AM

Going to use it in the t shirt press. A good application of PP or HDPE shredded with labels.

JohnNephew

My project today: engraving this sheet of aluminum for a mold for terrain for games like Dungeons & Dragons, with 1" squares and a flagstone pattern.

Very cool! How did you generate the 3D pattern?

Nice idea, what machine are you using for that mold? Some kind of sheet press most likely? Looking forward to see your first board. I assume a release agent is a must-have for this

JohnNephew

My project today: engraving this sheet of aluminum for a mold for terrain for games like Dungeons & Dragons, with 1" squares and a flagstone pattern.

Cool! I was thinking about doing something like this for an order. Let us know the results!

1

waterppk

Very cool! How did you generate the 3D pattern?

Hand-held dremel tool, making it up as I went!

2

1

DataWorm (PP Berlin)

Nice idea, what machine are you using for that mold? Some kind of sheet press most likely? Looking forward to see your first board. I assume a release agent is a must-have for this

Currently we have a cheap t-shirt press that we are using. Previous tests actually did fine without a release agent, but this is much more surface area so it seems like a good idea.

Yeah we also use t-shirt press without release agent on even metal sheets. But with so much texture i fear that plastic might be harder to remove, especially since your sheets are probably rather thin

I only gave it a little wet sanding by hand so far; after a test press or two I'm going to decide if I want to go over it with a power tool of wire brushing and/or polishing, to subdue the tool marks and probably assist demolding by wearing down corners and edges a bit.

1

Hello community. I am looking into the recylced glasses design and had a questsion on the lenses ?

6:32 AM

Did companys like Saju cut the lenses in house or get a order of pre cut lenses for the sunglasses molds ?

6:34 AM

Was looking into lense cutter machines and they are quite expensive and wastefull. So is there any precious plastic recomendation on the best way to source lenses for the recyled glasses ?

From my own experience, one can buy small lens squares and cut them yourself. If the material is thin, you can use scissors or use a laser cutter to get the profile. You will always have scrap material when making lenses into custom shapes.

JarvisSan

Was looking into lense cutter machines and they are quite expensive and wastefull. So is there any precious plastic recomendation on the best way to source lenses for the recyled glasses ?

1

7:37 AM

i made wood frames to replace my broken plastic ones and decided to make a sunglasses attachment. This doesn't answer your question though but it's a way to deal with the issue you're having

7:37 AM

Geoff (PBI NTB)

Triple = 300L x 100W x 165H (excluding the teeth)? Double = 200L x1 00W x 165H (ditto) Single = 100L x 100W x 165H (edited)

Triple - 29.5cm x 16cm x 10cm Double - 19.5cm x 16cm x 10cm Single - 9.5cm x 16cm x 10cm Teeth add additional 2.5cm Im sure there might be a slight variance in builds

Davide->PreciousPlasticRomagna

Last week I tried to make an aluminium mold with the small DIY CNC mill we have in the laboratory. It's just a test with something useful, a keychain for a friends association. Seems working, after some issue with the CAM. It has to be squared to dimensions, i used two scrap aluminium piece, it's just a matter of clamping them together with pins in place and mill out the excess material (and to make the chamfer for the nozzle).

Yesterday finished, today tested. Seems working fine!

2

1

7:38 PM

2

Working on the new keyring mold, for the makers hackers circle in which I'm working on the project.

11:05 AM

Hi! Has anyone had experience with bonding HDPE beams? If so, what adhesives did you use? My research is pointing me towards hot melt adhesives. Applied using a glue gun. These seem to be a smart choice because of their thermoplastic property, meaning that the bonded material can be remoulded again. Any advice would be greatly appreciated.

Our current plastic lumber production line explained in 2 min. https://youtu.be/ad8OdBhh028

Precious Plastic Philippines

Precious Plastic Philippines: Making Plastic Lumber from 100% Post ...

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2

Essdkay

Hi! Has anyone had experience with bonding HDPE beams? If so, what adhesives did you use? My research is pointing me towards hot melt adhesives. Applied using a glue gun. These seem to be a smart choice because of their thermoplastic property, meaning that the bonded material can be remoulded again. Any advice would be greatly appreciated.

Adhesives dont work so well with HDPE. Superglue cracks, PU peels off, rubber cement rubbs off... so you're mostly stuck with using mechanical fasteners or melting the ends of the HDPE planks so they melt together.

1

Ben - Precious Plastic Ciledug

Adhesives dont work so well with HDPE. Superglue cracks, PU peels off, rubber cement rubbs off... so you're mostly stuck with using mechanical fasteners or melting the ends of the HDPE planks so they melt together.

Thanks for the reply, Ben. I'm picking up some hot melt samples from a local packaging company. Will let you know how it goes.

Essdkay

Thanks for the reply, Ben. I'm picking up some hot melt samples from a local packaging company. Will let you know how it goes.

commercial machines use a combination of hot air guns and a extrusion machine of HDPE to bond the plastic

1

4:23 AM

Hey everybody! I'm an architecture student, currently designing circular building details with a group, and our theme is designing with waste. So I was thinking of trying to make a partition wall using a frame of precious plastic beams. I was wondering however if it would also be possible to extrude plastic profiles, for example a U-channel like this: (edited)

5:45 PM

maartenwichert

Hey everybody! I'm an architecture student, currently designing circular building details with a group, and our theme is designing with waste. So I was thinking of trying to make a partition wall using a frame of precious plastic beams. I was wondering however if it would also be possible to extrude plastic profiles, for example a U-channel like this: (edited)

a T shape has been done. I have a feeling a U channel should work. There will likely be some trial and error.

2:12 AM

https://community.preciousplastic.com/how-to/make-a-t-shape-beam-

Make a T-shape beam

Showcasing the process of creating custom shaped moulds for the extrusion machine. In this How-to we will look into making a mould for a T-shaped profile.

2:13 AM

You can use this for reference. If plastic does not flow to the sides of the U, you might need a little heat to help and maybe cap off the end for better filling... Just make sure your mould is strong enough to handle the pressure.

Interesting, thank you very much!

1

Hey guys! I'm relatively new here and I wanted to ask for some help as I could not find in the bazar. I am co-founder of NEO in Caracas, Venezuela and we currently have and injection machine and V2 shredder. We are currently doing small stuff like glasses, coasters, pots, etc. But, we were recently contacted to do trophies so I wanted to know if anyone had any previous experience with such moulds or if they even had some leads as to where we could commission some! Thanks a lot as any help is greatly appreciated

check this out, synthetic thatch roof... maybe this is the solution for the Project Kamp roof issue?

Butte (PP Philippines)

check this out, synthetic thatch roof... maybe this is the solution for the Project Kamp roof issue?

I met these guys a week or so ago. https://viroworld.com/ There is a company in Indonesia that makes this stuff. They have a lot of certifications and the material doesn't spread fire if it is set on fire. This plastic version is less flammable and requires far less maintenance than the natural version. I think they warrenty for something like 20 years.

maybe they add some borax to it...

4:38 AM

the new wood plane really makes it look nice. so far about a ton of lumber thru the machine. the blades are these tiny carbide squares. it appears that a full set of blades will last about 5 tons or so and then replacing the blades will be about 100 usd

1

Butte (PP Philippines)

the new wood plane really makes it look nice. so far about a ton of lumber thru the machine. the blades are these tiny carbide squares. it appears that a full set of blades will last about 5 tons or so and then replacing the blades will be about 100 usd

We have a few of the Byrd head style planers, you can find carbide really inexpensive on Aliexpress for them

waterppk

We have a few of the Byrd head style planers, you can find carbide really inexpensive on Aliexpress for them

it comes out to around 20-25usd per set of 10 and 4 sets to change them all. I get direct from Chia via Lazada

Butte (PP Philippines)

it comes out to around 20-25usd per set of 10 and 4 sets to change them all. I get direct from Chia via Lazada

https://www.aliexpress.us/item/3256802798551043.html I'm seeing $13.80 for 10 pcs w/free shipping to USA

the problem with ali express is the shipping. the postal system here is corrupt. nothing gets delivered. Lazada has its own courier and clears customs for me

1

2

10:04 AM

Working on seahorse keychain mold. Unfortunately the small CNC lose some steps in Z axis, and I have to restart all the work...

Davide->PreciousPlasticRomagna

Working on seahorse keychain mold. Unfortunately the small CNC lose some steps in Z axis, and I have to restart all the work...

Have you reduced the acceleration on the Z axis in your control software? It needs to be much lower than the X/Y since it has a lot more mass. One of our routers has a pneumatic balance cylinder on the Z to offset the mass which is another option

waterppk

Have you reduced the acceleration on the Z axis in your control software? It needs to be much lower than the X/Y since it has a lot more mass. One of our routers has a pneumatic balance cylinder on the Z to offset the mass which is another option

Yes, I'm used to industrial machinery so I didn't, but now I have to try.

1

Davide->PreciousPlasticRomagna

Yes, I'm used to industrial machinery so I didn't, but now I have to try.

If your gcode generator has an option for ramp or spiral plunge moves that'll also reduce the tool load and might fix the issue as well

waterppk

If your gcode generator has an option for ramp or spiral plunge moves that'll also reduce the tool load and might fix the issue as well

Yes, the process is made with spiral plunge with a very soft ramp (I don't remember the precise data, but we made something like 1.5° ramp for 0.25mm cutting deepth), seems that the issue comes with the rapid upward movement, since the depth increased because of the step loss and not decreased. The main reason I think is because the spindle is heavy, the owner changed the old woodworking one (mainly plastic) to a 1.5kw 24,000rpm liquid cooled one. He used it for a little while only to make RC models car parts at home (mainly to cut flat parts) and then he bring the machine to the nerd/Hackerspace bar in wich we are developing the project. First thing for now I have to change all the G0 movements to G1 F500 (simple task with Windows notepad), then probably the owner wants to change the motors to better ones (the machine is made with used printers motors and 12V drivers!)

Yesterday I tried with the modified G-code, seems working. Funny fact: Windows notepad takes longer than 10 minutes to convert all the G0 to G1F300 in the code. >70,000 lines.

10:44 AM

10:45 AM

I quit the finishing at 11pm, today or tomorrow I'm going to restart it.

You'll just have to leave it run overnight and either wake up when the fire alarm goes off or sleep well and wake up to a finished part

waterppk

You'll just have to leave it run overnight and either wake up when the fire alarm goes off or sleep well and wake up to a finished part

If the machine was mine and it was in my garage I can let it run overnight, but it isn't mine, and it is placed in the hackerspace/nerd bar in which I'm developing the project, ~5km from home, so I can't hear the fire alarm!

6:13 PM

However, first part of the mold finished.

6:14 PM

2

6:16 PM

Not perfect, but nothing some hand work can't fix. Unfortunately the CAM we have at job didn't have the mold finishing feature, so it is working as a fine-roughing path.

estl cam is a good cam program for that

I used to use MeshCAM but I haven't in many years, it was inexpensive (looks like it's $250 now but free 15 day trial) (edited)

3:54 PM

Fusion360 is free to hobbyists, it would work well for that model as well

At the moment I have some options about CAM programs, the main issue is that I didn't have enough time to learn how to use them.

Butte (PP Philippines)

commercial machines use a combination of hot air guns and a extrusion machine of HDPE to bond the plastic

Do you know what thickness the filament for these commercial machines usually is?

7:34 AM

I was thinking to make hot glue gun 'ammo' out of HDPE.

Alberto

Hey guys! I'm relatively new here and I wanted to ask for some help as I could not find in the bazar. I am co-founder of NEO in Caracas, Venezuela and we currently have and injection machine and V2 shredder. We are currently doing small stuff like glasses, coasters, pots, etc. But, we were recently contacted to do trophies so I wanted to know if anyone had any previous experience with such moulds or if they even had some leads as to where we could commission some! Thanks a lot as any help is greatly appreciated

Hey @Alberto have a look at the work we did in @projetosiri in Brazil. https://www.facebook.com/photo/?fbid=507136651096950&set=pcb.507136704430278 If you have doubts reach out

Mortar Art (Melb, AU)

I was thinking to make hot glue gun 'ammo' out of HDPE.

I think if you search for "hot melt" you can find those glue systems. Some pump glue from a reservoir for continuous use

waterppk

I think if you search for "hot melt" you can find those glue systems. Some pump glue from a reservoir for continuous use

i bought the HDPE plastc weld sticks but t really does not work unless you are both feeding in new material like welding and softening and stirring the base material into the weld. it is very much like TIG welding in many aspects

Butte (PP Philippines)

i bought the HDPE plastc weld sticks but t really does not work unless you are both feeding in new material like welding and softening and stirring the base material into the weld. it is very much like TIG welding in many aspects

my experience has been the same, I have a hot air gun version you really need to blend the polymers (base material and filler) to get it to link up and hold

Do you think that this is a good idea? A customer wanted us to make candle holders out of sheets like in the image but would fire burn or melt the hdpe?

1

waterppk

my experience has been the same, I have a hot air gun version you really need to blend the polymers (base material and filler) to get it to link up and hold

I bought the cheap hotair machine thinking I would set the world on fire with amazing welded plastic items. Instead I was rewarded with a crappy bond that broke easily. When I tried the soldering iron method I got okay result, but it appears that either it has to be a 2 man job, one with hot air gun, one with soldering iron and wielding a filler stick or the high dollar machine. I see boat builders are using the high dollar plastic welding machine, but so far I just do not have budget nor time to mess with it. this is likely a machine to be designed and fabbed down the road. Possible some hybrid hot HDPE filled caulk gun with a hot tip to blend and inject hot filler? A sort of 3D printer hot end with a motor and rod/filament? remains to be seen.

Cochon

Do you think that this is a good idea? A customer wanted us to make candle holders out of sheets like in the image but would fire burn or melt the hdpe?

fire hazard. you will need more insulation between the two. OR switch to LED tea light inserts that are the same shape... LED Tea lights last forever. I used to laser some plywood/paper lanterns in the Japanese style with those and they worked for many days.

Cochon

Do you think that this is a good idea? A customer wanted us to make candle holders out of sheets like in the image but would fire burn or melt the hdpe?

It is difficult to say. Wouldn't be too difficult to make one and see what happens.

Hey there, does anyone have some tips to reduce the amount of holes in the plate?

Grosch

Hey there, does anyone have some tips to reduce the amount of holes in the plate?

I’m also having some issues

10:19 AM

Even bigger holes

10:19 AM

And weird craters

A non precious plastic shop in Manila is making these boards.

10:22 AM

they got a big machine that pumps hot oil thru the plates instead of heating the plate directly. they press 5 every 90 min or so.

2

10:23 AM

10:24 AM

it almost looks like granite. we have two companies in Manila making this product.

Butte (PP Philippines)

they got a big machine that pumps hot oil thru the plates instead of heating the plate directly. they press 5 every 90 min or so.

Fancy stuff

️

10:26 AM

Meanwhile I’m using a shirt press haha

10:26 AM

Works half the time tho but can’t seem to figure out the reason for those craters

Halcyon2024

I’m also having some issues

But u have only big holes and no small ones xD

2:47 PM

Looks like big air bubbles

Halcyon2024

I’m also having some issues

I think I know what's going on here. You need to allow your plastic to melt down first before you press it. But if you're using a shirt press, that might be a bit impossible.

Does anyone have experience injecting glasses that could give us some pointers?

Yes, what is the issue? @Alberto

Fritz @easymoulds

Yes, what is the issue? @Alberto

Thanks Fritz! We’re having a really “perfect frame” as we either have incomplete shots are the one seen below (grey frames) or we have a full shot but it is a little fragile and the rim where the crystal fits breaks apart (blue frames). This is all done with PP but even then it seems to be a difference between the type of PP we use (grey are dvd and xbox cd cases, blue are blu-ray cases). Not sure if there is one type of PP that we should be looking to use

9:52 PM

1

Not sure what you mean with "crystal" - but for the incomplete shots I would start to preheat the mould to 60-80°C (and track the temperature during the process) . Also timing in general becomes very critical on thin geometries. So you want to track all your timings (preheat, injection, idle time during ejection etc.) this gives you some info where the issue is. Also the material can be contaminated sometimes, or can have unknown additives. So having some known material at hand really helps. If you just start out, virgin material or shredding some 3d print filament is a good idea for tracking errors. You want one perfect shot and start from there to check for process variables (1), material variables/mixes (2), mould issues/changes (3)

Ben - Precious Plastic Ciledug

I think I know what's going on here. You need to allow your plastic to melt down first before you press it. But if you're using a shirt press, that might be a bit impossible.

yea I think I pressed it too fast that the flakes from the back sides are pushed thus creating these holes

4:54 AM

@Ben - Precious Plastic Ciledug thanks for the input

Grosch

But u have only big holes and no small ones xD

yeaa, however bigger holes can still be fixed with a heat gun

Alberto

Thanks Fritz! We’re having a really “perfect frame” as we either have incomplete shots are the one seen below (grey frames) or we have a full shot but it is a little fragile and the rim where the crystal fits breaks apart (blue frames). This is all done with PP but even then it seems to be a difference between the type of PP we use (grey are dvd and xbox cd cases, blue are blu-ray cases). Not sure if there is one type of PP that we should be looking to use

would recycled plastic cause any allergic issues when in direct contact with the skin?

Halcyon2024

would recycled plastic cause any allergic issues when in direct contact with the skin?

Not that I am aware of

Btw anyone has any advice on what size of flakes is best for making sheets? Does smaller flakes creates more bubble?

We have just had the unfortunate experience of accidentally bending one of our moulds when trying our new log press injection machine. Now when we press the plastic comes out from between the mould as it is a small gap between the two sides. Has this happened to anyone else in here? And did you manage to fix the mould in some way?

mould flash is definitely a thing even with an unbent mould, maybe your pressure is too high? Plastic too hot? Mould too hot?

waterppk

mould flash is definitely a thing even with an unbent mould, maybe your pressure is too high? Plastic too hot? Mould too hot?

Yes we've had that before but now it does not matter the pressure or temprature. The plastic still unfortunately finds its way out of the cracks.

flip the mould around, put it in the machine, and inject to bend it back?

(I'm KIDDING!)

M0lnet

We have just had the unfortunate experience of accidentally bending one of our moulds when trying our new log press injection machine. Now when we press the plastic comes out from between the mould as it is a small gap between the two sides. Has this happened to anyone else in here? And did you manage to fix the mould in some way?

That is very unfortunate. The pressure was definitely too high for the mould to handle. I think the mould it too thin to be able to withstand the relatively high pressure such a hydraulic injection machine is able to produce. (There is a reason why industrial moulds are massive). You could try to reface or flatten both sides of the mould in a milling machine. Just take off the slightest bit so they are flat again.

GTalsma

That is very unfortunate. The pressure was definitely too high for the mould to handle. I think the mould it too thin to be able to withstand the relatively high pressure such a hydraulic injection machine is able to produce. (There is a reason why industrial moulds are massive). You could try to reface or flatten both sides of the mould in a milling machine. Just take off the slightest bit so they are flat again.

Yea we figured. Thank you for your suggestion! Unfortunately we do not have a milling machine at our disposal.

Halcyon2024

I’m also having some issues

Does it stick to the sheet material you are using? It looks like it sticks as it cools down. Maybe try with a baking paper and see if it still happens. The baking paper is covered in silicon and does not stick to the plastic. If that fixes it, you need to work on the surface of your material

Grosch

Hey there, does anyone have some tips to reduce the amount of holes in the plate?

I had a similar problem but as I increased the pressure, it was more or less fixed

Cochon

I had a similar problem but as I increased the pressure, it was more or less fixed

ah nice thanks ^^

M0lnet

We have just had the unfortunate experience of accidentally bending one of our moulds when trying our new log press injection machine. Now when we press the plastic comes out from between the mould as it is a small gap between the two sides. Has this happened to anyone else in here? And did you manage to fix the mould in some way?

The injection pressure build an enormous force inside the mold. I'm using an hydraulic press for my injector, this needs some calculations to be done. I suggest you to modify the oil circuit to add a maximum pressure limiting valve and a manometer, as a starting point. There's a direct correlation between oil pressure and plastic injection pressure, it's a relation between the areas of the piston. For example with an hydraulic cylinder with an area of 10cm² pushing an injector piston of 5cm², the oil pressure equals to 2x injection pressure. This data multiplies for the area of the mold cavity. If the mold cavity has a 50cm² area, you have to multiply that for the injection pressure. The results are usually very high, for example for my plant pots mold, 7cm diameter made in thick C45 steel I'm using 4 M10 screws in 12.9steel. Usually I'm injecting those with a 180bar oil pressure. The hydraulic cylinder area is 19.625mm² (50mm diameter), the injector barrel is 30mm, so it has 7.065cm², so the pressure factor is 2.78:1. 180*2.78=~500bar, so 500kg/cm². 70mm diameter for the pot mold means it has an area of ~38.5cm². 38.5cm² with a pressure of 500bar means that the plastic in the mold is pushing the two halves with a force of 19'250kg. Over 19tons. That's why I'm suggesting to add a pressure limiting valve, there are huge forces involved. With a log splitter machine making for example 5t, if you are running a 25mm ID barrel like the official one, you are reaching over 1000bar of injection pressure. It isn't only too high for the mold, but also for the barrel itself, with that pressure it can crack easily, spraying molten plastic everywhere. Take care, apply some science and stay safe. Bending a mold isn't a big issue, being in the way of a 200°C molten plastic jet can be a lot worse. Said that, if the mold is made with aluminium, you can skim the mating surfaces using a piece of glass/granite and some wet sand paper.

12:56 AM

It isn't the best way, but it is simple and it works. Start with a 180 grit, spray some water on the paper to keep it clean during the job and move the mold on it making a little pressure. When it is flat, you can finish it with a higher grit.

Just saying. I tried with 220bar oil pressure (so ~610 bar injection pressure on my machine). As I said, 4x M10 screws in 12.9steel (the best on the market), screwed with the torque you can make with a 150mm allen key, the mating surfaces on the mold are made with industrial CNC lathe I'm working with, so they are flat and smooth, and the plastic find its way between them, making some nasty flashings...

Seems that with that pressure even the good screws find hard to keep the mold closed.

1:08 AM

1

Does anyone have recommendations to remove these imperfections? Grinder, sand paper, cutter or scissors? We’re afraid of damaging the legs of our glasses

4:42 PM

Alberto

Does anyone have recommendations to remove these imperfections? Grinder, sand paper, cutter or scissors? We’re afraid of damaging the legs of our glasses

@Alberto nail cutters, but for the side of the nail. Quita padrastros, en México Ill look for one piece lost in my shop, to share a picture This tool ooks like a glass leg, just with a

pointy of metal

Alberto

Does anyone have recommendations to remove these imperfections? Grinder, sand paper, cutter or scissors? We’re afraid of damaging the legs of our glasses

Try to reduce those flashings by closing the mold better and reducing slightly the plastic temperature and pressure. If the mold is precise enough to close with the mating surfaces in contact, and if the pressure closing the mold is enough to fight against the forces induced by the plastic pressure, flashings aren't an issue. Obviously a hot mold, with too much pressure and too hot plastic helps it to pass between the surfaces.

11:53 AM

The rule is to keep pressure and temperatures at the minimum to achieve the total fill of the mold.

I saw in bazar that most sheet frames (<40cm) are made of steel. Is there any reason to use steel rather than alu? Does that also make sense for the large sheet press? If you want to create a thick 1m² sheet in the press, I assume the frame weight becomes more crucial for usability

11:58 PM

In fact for the sheet press I have neither seen any hints/drawings what material in which thickness is suggested to build a larger mould. Did I just miss that or is that information simply not written down anywhere?

DataWorm (PP Berlin)

I saw in bazar that most sheet frames (<40cm) are made of steel. Is there any reason to use steel rather than alu? Does that also make sense for the large sheet press? If you want to create a thick 1m² sheet in the press, I assume the frame weight becomes more crucial for usability

Steel is tougher than aluminium. The common mild steel, the one you can use to make a fence, has a tensile strength higher than most of the fancy aluminium alloy. And a good mild steel has a tensile strength higher than the best Ergal alloy. Add that it is more flexible, it is weldable and it is cheaper. The biggest downside is the density, steel is heavier. A sheet press made with aluminium have to be a lot beefier to whitstand the load, so yes, it can be lighter if you use a good aluminium alloy, but not so much. And good aluminium alloys aren't weldable, they have a higher heat conductivity (so you have to add more insulation, or more heating elements)...

Meanwhile... We had some issues with the milling machine we have in the laboratory, it has small stepper motors and they were not well set, so the machine lose some steps. Now it's fixed. Yesterday I finished the second half of the mold, today I tried it. Seems working. The seahorse is 40mm high, without the ring. i made the gate 0.8mm diameter, but it was too small, so I filed it with a small curved file to enlarge it at ~1/1.2mm diameter. The tip of the tail is something like 0.6mm in diameter. ~40° mold temperature, 210°C barrel and 235° nozzle temperatures. Injected with ~500bar pressure.

1

9:37 PM

9:38 PM

I'm very happy with the results!

3

1

Looks really great, well done!

1

Davide->PreciousPlasticRomagna

Steel is tougher than aluminium. The common mild steel, the one you can use to make a fence, has a tensile strength higher than most of the fancy aluminium alloy. And a good mild steel has a tensile strength higher than the best Ergal alloy. Add that it is more flexible, it is weldable and it is cheaper. The biggest downside is the density, steel is heavier. A sheet press made with aluminium have to be a lot beefier to whitstand the load, so yes, it can be lighter if you use a good aluminium alloy, but not so much. And good aluminium alloys aren't weldable, they have a higher heat conductivity (so you have to add more insulation, or more heating elements)...

Sorry, maybe my question was a bit misleading. What I mean with sheet frame is rather the "sheet mould" which you fill with plastic and then put that mould inside the sheet press (or rather oven in my current situation). So basically something like this in much larger: https://bazar.preciousplastic.com/moulds/compression-moulds/sheetprees-mould-a4/

SheetPress Mould A4

1:52 AM

So since that mould should be more or less enclosed inside that heated zone, the thermal conductivity of alu might actually be a benefit cause the plastic inside might heat up and melt faster and once you take the frame out, it can also cooldown faster. And as you said the density/weight of alu is smaller, so carrying/moving the filled mould might be much easier

1

Cochon

Does it stick to the sheet material you are using? It looks like it sticks as it cools down. Maybe try with a baking paper and see if it still happens. The baking paper is covered in silicon and does not stick to the plastic. If that fixes it, you need to work on the surface of your material

hey thanks for the input, I used to place baking paper on top and bottom of it but it creates an uneven surface. I use metal now layered with silicone oil.

DataWorm (PP Berlin)

So since that mould should be more or less enclosed inside that heated zone, the thermal conductivity of alu might actually be a benefit cause the plastic inside might heat up and melt faster and once you take the frame out, it can also cooldown faster. And as you said the density/weight of alu is smaller, so carrying/moving the filled mould might be much easier

That's ok, aluminium can be a good material for that, but maybe it's too soft to withstand the pressure, at least if the sheet is thin.

1

2:05 AM

Since tomorrow (too optimistic...later, it's 2am here!) I'm going to visit some relatives and I want to bring some gift, I made some other seahorses. 70+ of them in less than two hours, not bad.

7

Hii, new here, and am posting on behalf of Project Borneo, a Malaysian conservation company and UK-registered charity offering alternative solutions and sustainable funding for endangered wildlife in Borneo. Please see here: https://www.projectborneo.org/ With a view to raising funds for the charity, we are currently looking at creating two chess sets made from recycled plastic - a standard (Staunton) set, and a bespoke animal-themed set, and are looking for someone who can provide us with steel moulds for each set (the final pieces will be made from injected plastic). We will also need help designing the animal set, which may or may not be done by the same person creating the moulds. Obviously, we’d be happy to pay, or maybe there are people out there able to offer their services in exchange for promotion to our audience. Either way, we’re keen to get the ball rolling with this asap, and any help and advice at all would be greatly appreciated. Thanks in advance, Mark

Project Borneo | Conservation & Animal Welfare charity

Project Borneo - Click to donate, or find out about our ethical volunteering opportunities and tours in Borneo.

finchmark

Hii, new here, and am posting on behalf of Project Borneo, a Malaysian conservation company and UK-registered charity offering alternative solutions and sustainable funding for endangered wildlife in Borneo. Please see here: https://www.projectborneo.org/ With a view to raising funds for the charity, we are currently looking at creating two chess sets made from recycled plastic - a standard (Staunton) set, and a bespoke animal-themed set, and are looking for someone who can provide us with steel moulds for each set (the final pieces will be made from injected plastic). We will also need help designing the animal set, which may or may not be done by the same person creating the moulds. Obviously, we’d be happy to pay, or maybe there are people out there able to offer their services in exchange for promotion to our audience. Either way, we’re keen to get the ball rolling with this asap, and any help and advice at all would be greatly appreciated. Thanks in advance, Mark

are you looking to have them professionally injection moulded or make them yourself? The only reason I ask is you probably don't need steel moulds (aluminum would be sufficient) unless you're using a high pressure machine or making thousands of them. You also should start with someone who understands injection moulding geometry for the design or you're going to have someone who makes a really cool design for you that's literally impossible to manufacture

1

waterppk

are you looking to have them professionally injection moulded or make them yourself? The only reason I ask is you probably don't need steel moulds (aluminum would be sufficient) unless you're using a high pressure machine or making thousands of them. You also should start with someone who understands injection moulding geometry for the design or you're going to have someone who makes a really cool design for you that's literally impossible to manufacture

Many thanks for that - we'd be looking at making them ourselves, and it won't be going into the 1000s (or maybe even 1000s) - so yes, aluminum will probably suffice. And many thanks for the other point -

Halcyon2024

yea I think I pressed it too fast that the flakes from the back sides are pushed thus creating these holes

you could try melting for longer and using clamps to add pressure.

finchmark

Hii, new here, and am posting on behalf of Project Borneo, a Malaysian conservation company and UK-registered charity offering alternative solutions and sustainable funding for endangered wildlife in Borneo. Please see here: https://www.projectborneo.org/ With a view to raising funds for the charity, we are currently looking at creating two chess sets made from recycled plastic - a standard (Staunton) set, and a bespoke animal-themed set, and are looking for someone who can provide us with steel moulds for each set (the final pieces will be made from injected plastic). We will also need help designing the animal set, which may or may not be done by the same person creating the moulds. Obviously, we’d be happy to pay, or maybe there are people out there able to offer their services in exchange for promotion to our audience. Either way, we’re keen to get the ball rolling with this asap, and any help and advice at all would be greatly appreciated. Thanks in advance, Mark

Steel is sturdier but it is costly and more difficult to work with. All depends on how many parts you need and on who make them. Damaging an alu mold is less difficult than it seems.

One down...29 to go

1

1

Ben - Precious Plastic Ciledug

One down...29 to go

How long does it take to make one?

waterppk

How long does it take to make one?

1 bench = 2 part a + 2 part b. Each part is about 3.2kg. About 12 minutes per part. Plus there's the time required for cutting the parts for the feet and joints. 1 bench = 1 hour (excluding planks)

gotcha, I have two extruders here (commercial overmolding machines I think, they're tiny) so I was trying to get a gauge for extrusion time

5:12 AM

one was converted to horizontal and needs flights (augers) where the hopper is, the other I just got adapted to output to NPT (USA pipe) threads so I need to test the vertical one now. We're going to try to make lumber but should be able to do other things

5:12 AM

waterppk

one was converted to horizontal and needs flights (augers) where the hopper is, the other I just got adapted to output to NPT (USA pipe) threads so I need to test the vertical one now. We're going to try to make lumber but should be able to do other things

Soooo wanna see something weird for attaching planks to a nozzle?

6:46 AM

6:48 AM

This actually works and makes it super easy for putting on or taking off moulds. Sure, the end opens but when you put the whole mould into a cooling tank/tub/barrel its not an issue. It doesnt seem to stick to the steel plate either.

waterppk

gotcha, I have two extruders here (commercial overmolding machines I think, they're tiny) so I was trying to get a gauge for extrusion time

I've seen machines that look almost like shredder pro size but their capacity was maybe 50kg up to 100kg per hour. Each heater band was 1kw and there was 7 of them. So it's hard to say what you have. Maybe do a small sample size of 500g or 1kg and see how long that takes to extrude. I don't like wasting material though but it's important to know what your flow rate is.

yeah these are only 1500W input (3x band heaters @ 500W each) so it's going to be pretty low output. I counted 80rpm at the screw, if I end up pulling the barrel to add flights to the screw I'll measure it. I took a polymers course in college but it's been long enough I don't remember anything (edited)

vise grips are awesome and easy to replace if they get damaged/covered in plastic

Our extruder had a straight threaded output so we ended up converting it over to NPT so it was compatible with common US threads, if we end up in production making boards something quick like that will be a much better option

waterppk

vise grips are awesome and easy to replace if they get damaged/covered in plastic

Our extruder had a straight threaded output so we ended up converting it over to NPT so it was compatible with common US threads, if we end up in production making boards something quick like that will be a much better option

Yeah seriously, I didn't expect these vice grips to work. What you can do with your threaded connecter is to just weld a coupling to steel plate that's of the appropriate size for whatever you're connecting to it. I was previously under the impression it needs to be a much more significant connection but that doesn't seem to be the case.

waterppk

yeah these are only 1500W input (3x band heaters @ 500W each) so it's going to be pretty low output. I counted 80rpm at the screw, if I end up pulling the barrel to add flights to the screw I'll measure it. I took a polymers course in college but it's been long enough I don't remember anything (edited)

I saw a screw a while back and the pitch (distance between flights) were close. This means the material has to travel a lot further to get to the end. So maybe you don't need more flights but instead fewer if you want a faster rate?

Hey guys. Im working on the workshop calculator. Does anyone knows how can i tell excel to calculate more products that out business will produce in order to have a reflective balance sheet? because it only allows me to have 11 products out of the 27

Hey! We're currently working with a coasters/medals hexagonal mold that makes 4 at a time. We are currently closing on a deadline to deliver 160 of them but we are still having issues injecting into the mold, as they mostly come out with some imperfections (see below, left one if what we aim for and the right is the most recent mold and what we mostly get out of the mold. We're working with gold PP, temperatures around 250ºC and we let the plastic melt for around 16 minutes before we inject. What could be causing the things seen on the right coaster/medal?

6:36 PM

have you tried controlling/monitoring the mould temperature? A hotter mould should be easier to fill/will reduce pressure needed to fill

We do preheat the mold, but maybe we need to increase the temperature

definitely worth trying, otherwise increasing injection speed and/or pressure will help as well

Another thing to experiment with is rapid cooling after injection.

Alberto

Click to see attachment 🖼️

Are you holding down after injecting? There's basically 3 parts to the injection process. Injection- material is injected into the mould. Holding- the mould is full, but injection pressure is maintained to help reduce deformities due to cooling. Release-plunger is retracted and you can release your mould.

1:27 AM

This is just focusing on the mould injection side. You can also have issues if you're trying to inject too much and there's simply not enough material in the injection machine.

Ben - Precious Plastic Ciledug

One down...29 to go

how do you attach those bars? will it hold?

Cochon

Does it stick to the sheet material you are using? It looks like it sticks as it cools down. Maybe try with a baking paper and see if it still happens. The baking paper is covered in silicon and does not stick to the plastic. If that fixes it, you need to work on the surface of your material

am using stainless steel covered with silicone oil. maybe the viscosity is too high? any idea what's the right amount?

M0lnet

We have just had the unfortunate experience of accidentally bending one of our moulds when trying our new log press injection machine. Now when we press the plastic comes out from between the mould as it is a small gap between the two sides. Has this happened to anyone else in here? And did you manage to fix the mould in some way?

lion king moment

Halcyon2024

how do you attach those bars? will it hold?

I use a long furniture screw and a barrel nut. The joint helps too.

Ben - Precious Plastic Ciledug

I use a long furniture screw and a barrel nut. The joint helps too.

did you weld the plastics as well?

Halcyon2024

did you weld the plastics as well?

no, honestly i have never had big success with plastic welding. This is just held together with furniture screw and barrel nut. I think the cooler way to do it is to do some fancy joint work that requires no screws, but i dont trust my skillset for something like that (yet)

1

Alberto

Hey! We're currently working with a coasters/medals hexagonal mold that makes 4 at a time. We are currently closing on a deadline to deliver 160 of them but we are still having issues injecting into the mold, as they mostly come out with some imperfections (see below, left one if what we aim for and the right is the most recent mold and what we mostly get out of the mold. We're working with gold PP, temperatures around 250ºC and we let the plastic melt for around 16 minutes before we inject. What could be causing the things seen on the right coaster/medal?

I feel the temperature you've set is too high for PP. I've had the most success with injecting pp at 190-200ºC. I realised that when I went above 225ºC the plastic started to degrade and burn. It's viscosity would also change. I'd recommend using lower temperature, and increasing holding time after injection. All the best

M0lnet

We have just had the unfortunate experience of accidentally bending one of our moulds when trying our new log press injection machine. Now when we press the plastic comes out from between the mould as it is a small gap between the two sides. Has this happened to anyone else in here? And did you manage to fix the mould in some way?

You probably had too high of pressure and too low of clamping force or perhaps not proper enough clamping force. Have you tried clamping it down to see if it gets squished back together?

10:00 AM

oh woops that was a month ago....not sure what i was doing looking up there hah

Hi all, I am posting as a representative of the Project Borneo charity in Borneo, Malaysia, which specialises in protecting endangered species, especially orangutans. The charity's CEO is an English citizen and Project Borneo is registered as a UK charity (charity number 1136449). The charity is constantly trying to fundraise in order to continue its essential work, and at present is commissioning unique chess sets to further generate funds. Malaysia does not recycle plastic as a rule, so Project Borneo is seeking to develop two chess sets - a standard (Staunton) set, and an "animal-themed" set - using recycled plastic, that would otherwise go to landfill. We are looking to source artists/designers who would be willing to create steel moulds for the pieces for us, and in return, Project Borneo would promote their work on its platforms. Please note all profits generated from the retail of the chess sets will go straight back into supporting the charity's vital work. If there are any students interested in engaging with this project, please let me know and I will be very pleased to provide more information, Best regards, Mark Finch (edited)

How do I get ink on plastic like seen here?

that's probably pad printed, might be able to screen print but I don't know what kind of ink you'd use

tonelessbod

How do I get ink on plastic like seen here?

Look up UV printing

Ben - Precious Plastic Ciledug

Look up UV printing

tried it just peels right off

tonelessbod

tried it just peels right off

Well... These stuck

1

3:54 AM

There's always going to be a durability issue. Even with your pcb print, if you use it as a coaster or something where people are touching and rubbing on, it will wear out.

3:55 AM

You can do UV print and then epoxy coat for protecting it, but you'll get a glare from the recycling community if you do that.

Hello! Does anyone design mould? We are looking to create a trophy mould

Alberto

Hello! Does anyone design mould? We are looking to create a trophy mould

Maybe @Thomas Peterberns | Johannplasto who posted this a few weeks ago: https://discord.com/channels/586676777334865928/968146422396514384/1093172863659417660 (edited)

Alberto

Hello! Does anyone design mould? We are looking to create a trophy mould

Sure, do you have a drawing?

im looking to have a mold made for these outlet covers. i believe it will be an incredibly marketable product in the US. let me know if anyone picks up on this. thanks!

2

1

GarrettCadou

im looking to have a mold made for these outlet covers. i believe it will be an incredibly marketable product in the US. let me know if anyone picks up on this. thanks!

There's some things to be aware of ratings-wise for wall covers: https://www.eng-tips.com/viewthread.cfm?qid=244889 some information on the UL website: https://www.ul.com/services/attachment-plug-and-receptacle-safety-evaluations I don't think HDPE/PP that are commonly used here are going to meet the flame safety standard but that wouldn't stop you from selling them

Attachment Plug and Receptacle Safety Evaluations

UL Solutions can help you quickly and efficiently navigate through safety evaluations for receptacles and attachment plugs.

2

waterppk

There's some things to be aware of ratings-wise for wall covers: https://www.eng-tips.com/viewthread.cfm?qid=244889 some information on the UL website: https://www.ul.com/services/attachment-plug-and-receptacle-safety-evaluations I don't think HDPE/PP that are commonly used here are going to meet the flame safety standard but that wouldn't stop you from selling them

thank you very much for the info! safety and legality is definitely something i have considered. i'd like to get into production with a basic model asap so i can start testing

Ben - Precious Plastic Ciledug

One down...29 to go

That's a state-of-the-art washing machine.

3:23 AM

Bench moulds done.

2

First bench legs and plank extruded.

3

Hello every one! I would like to do a SURF FIN project. Could someone share the computer file to create the metal mold? #fin #surf

Geoff (PBI NTB)

Bench moulds done.

Is that galvanizer steel?

Where do air bubbles in a compression mold go? -are they squeezed out with flashing, and/or does a portion remain as highly compressed bubbles? I wonder if very small, highly pressurized bubbles are incorporated into the product. Should I design the compression mold with slop, to allow for flashing and the escape of air? -but if I do that, aren't I limiting how much pressure can be applied to the plastic mass as it is compressed? I sense a paradox of need! (edited)

Andrés Romero

Is that galvanizer steel?

Yes. 1.8mm 50x50

Christopher - Unmake Plastic

Where do air bubbles in a compression mold go? -are they squeezed out with flashing, and/or does a portion remain as highly compressed bubbles? I wonder if very small, highly pressurized bubbles are incorporated into the product. Should I design the compression mold with slop, to allow for flashing and the escape of air? -but if I do that, aren't I limiting how much pressure can be applied to the plastic mass as it is compressed? I sense a paradox of need! (edited)

@Alberto In a compression mold, they remain in the product. In injection one, they tend to escape, the more as the smaller the gate (passing in a small passage they tend to blow out). In extruder air tend to escape during the compression, exiting from the hopper.

Geoff (PBI NTB)

Yes. 1.8mm 50x50

FYI, galvanization starts becoming toxic around 200° C. Please take care of your health and ventilate/respirate properly if your galvanized parts are seeing any type of heat in that range!

Davide->PreciousPlasticRomagna

@Alberto In a compression mold, they remain in the product. In injection one, they tend to escape, the more as the smaller the gate (passing in a small passage they tend to blow out). In extruder air tend to escape during the compression, exiting from the hopper.

I hear that- but isn't the premise of interval compression with a sheet mold to minimize bubbles?

Erik72

FYI, galvanization starts becoming toxic around 200° C. Please take care of your health and ventilate/respirate properly if your galvanized parts are seeing any type of heat in that range!

Better to eliminate the zinc cover with some sulfuric acid...

1

Christopher - Unmake Plastic

I hear that- but isn't the premise of interval compression with a sheet mold to minimize bubbles?

I don't have experience with sheet making, I'm sorry.

Erik72

FYI, galvanization starts becoming toxic around 200° C. Please take care of your health and ventilate/respirate properly if your galvanized parts are seeing any type of heat in that range!

Do you recommend something else?

Andrés Romero

Do you recommend something else?

Yes, plain steel that has not been galvanized.

1

the my resin-printed injection moulding tests with El Tornillo press shredder and injection key are going well. At 50 and accounting and hardly any defects on the mold (edited)

2

9:31 AM

metal base with a printed plate seem to solve the heat transfer problem i been getting for full resin molds

5

9:33 AM

Could be the best way to use these printed moulds and not add to plastic waste with broken moulds

Erik72

FYI, galvanization starts becoming toxic around 200° C. Please take care of your health and ventilate/respirate properly if your galvanized parts are seeing any type of heat in that range!

Thanks. I will take note of that.

Reviewing the Brick Mold V4.0 page ( https://community.preciousplastic.com/how-to/brick-mould ), I can find no indication of material specifications! Preferred grade of steal- and, most importantly, thickness! Anybody know? Slots are cut at 5.5 wide... so... 5 mm? (edited)

Brick mould

Recycled plastic has the potential to replace more conventional and wasteful building materials such as hollow blocks. In this How-to, you will learn how to assemble the mould for the extruded plastic brick, ready for production. This brick was developed with the Extrusion Pro machine. Learn here how to build it:

Hiya guys , I’m having a real bother getting a good or even complete flower pot , I’m using a plasticprenur injection machine. My process so far is to heat the mold to 200C and use HDPE Flakes melted at 230C , but the plastic never flows all the way down the mold. Any help would be amazing.

reSource Precious Plastics

Hiya guys , I’m having a real bother getting a good or even complete flower pot , I’m using a plasticprenur injection machine. My process so far is to heat the mold to 200C and use HDPE Flakes melted at 230C , but the plastic never flows all the way down the mold. Any help would be amazing.

I'm just repeating something I read- I have zero first hand experience. As I recall, one maker reported better filling with less preheating of the mold; the explanation given was that as plastic cooled around the entry gate, the effective aperture of the gate constricted, resulting in plastic passing the constriction under higher pressure. I'm not sure that makes any sense.

Christopher - Unmake Plastic

I'm just repeating something I read- I have zero first hand experience. As I recall, one maker reported better filling with less preheating of the mold; the explanation given was that as plastic cooled around the entry gate, the effective aperture of the gate constricted, resulting in plastic passing the constriction under higher pressure. I'm not sure that makes any sense.

Thanks dude anything is useful, I shall give it a try

Christopher - Unmake Plastic

Reviewing the Brick Mold V4.0 page ( https://community.preciousplastic.com/how-to/brick-mould ), I can find no indication of material specifications! Preferred grade of steal- and, most importantly, thickness! Anybody know? Slots are cut at 5.5 wide... so... 5 mm? (edited)

The brick mould material thicknesses are in the DXF laser cutting file names. from memory. Yes 5mm mild steel I believe.

1

Geoff (PBI NTB)

The brick mould material thicknesses are in the DXF laser cutting file names. from memory. Yes 5mm mild steel I believe.

Thanks, Geoff- a "5" is present in many of the file names... as are 10, 2, and 4, with no unit indication.

Christopher - Unmake Plastic

Thanks, Geoff- a "5" is present in many of the file names... as are 10, 2, and 4, with no unit indication.

The 5 is the thickness and the second number is the quantity of that part to cut. i.e. BA5x2.dwg = BA is the part ID which is etched in the centre of the part and also at Adjoining sections so you know which part goes where on assembly, 5 is material thickness and x2 is the quantity to be cut. .dwg is the file type.

1

Designing a large billet compression mold- 20"x14"x8"/50.8cmX35.56cmX20.32cm, receiving about 92.59 lbs/42.49 kilos of shred. The mold will be filled, heated in a convection oven, the compression lid affixed, 6 large perimeter screws delivering clamping force through compressed springs, then retorqued at intervals until annealing. I wonder about the needed clamping force. A Sheet Press employs an 8-tonn jack- which, in addition to clamping force, is tasked with raising the entire heating bed, mold, and plastic shred. The compressed area of the sheet press is ~10,000 sq cm, volume 20,000 cubic cm (for a 2 cm thick sheet), & 22 kilos; by contrast, the proposed mold features a compressed area of 2,090.98 sq cm, volume 42,487.656 sq cm, and weight of 42.49 kilos. What is the more critical aspect for determining clamping force needs- area, or volume? With a sheet press, the mold is overfilled, then the jack is progressively applied until the upper press meets the mold top- pressure, in part, depends on the viscosity of the plastic! When designing the billet mold's compression lid, I'm inclined to build it as a stepped plunger, rather than a flat plate, to allow space in the mold for the shred, & to retain pressure; the alternative would be shred melted to fill the mold before compression, then overfilled & flat compression lid applied- the concern there being that most of the pressure would bleed out the side before acting to purge deep air bubbles. Thoughts? Lastly, many small compression molds are just single-layer female and male shells, while brick injection molds are replete with ribs all around. All things considered, I'm inclined to rib-reinforce this monstrous molds; that said, due to commonly available stock dimensions, the billet mold will likely be fabricated from .635 mm (1/4") mild steel, for a combined billet/mold weight of near 90 kg!!! I'd love someone to give me cause not to add the rib weight!!

Christopher - Unmake Plastic

Designing a large billet compression mold- 20"x14"x8"/50.8cmX35.56cmX20.32cm, receiving about 92.59 lbs/42.49 kilos of shred. The mold will be filled, heated in a convection oven, the compression lid affixed, 6 large perimeter screws delivering clamping force through compressed springs, then retorqued at intervals until annealing. I wonder about the needed clamping force. A Sheet Press employs an 8-tonn jack- which, in addition to clamping force, is tasked with raising the entire heating bed, mold, and plastic shred. The compressed area of the sheet press is ~10,000 sq cm, volume 20,000 cubic cm (for a 2 cm thick sheet), & 22 kilos; by contrast, the proposed mold features a compressed area of 2,090.98 sq cm, volume 42,487.656 sq cm, and weight of 42.49 kilos. What is the more critical aspect for determining clamping force needs- area, or volume? With a sheet press, the mold is overfilled, then the jack is progressively applied until the upper press meets the mold top- pressure, in part, depends on the viscosity of the plastic! When designing the billet mold's compression lid, I'm inclined to build it as a stepped plunger, rather than a flat plate, to allow space in the mold for the shred, & to retain pressure; the alternative would be shred melted to fill the mold before compression, then overfilled & flat compression lid applied- the concern there being that most of the pressure would bleed out the side before acting to purge deep air bubbles. Thoughts? Lastly, many small compression molds are just single-layer female and male shells, while brick injection molds are replete with ribs all around. All things considered, I'm inclined to rib-reinforce this monstrous molds; that said, due to commonly available stock dimensions, the billet mold will likely be fabricated from .635 mm (1/4") mild steel, for a combined billet/mold weight of near 90 kg!!! I'd love someone to give me cause not to add the rib weight!!

If you apply 8 tons of force on the sheet press you will be bending and breaking things. The sheet press uses an 8ton jack because it's what's available for building the machine. Your focus should instead be more on the spring that is used and how far it is compressed, this gives you a better idea of how much force is used. Proper springs will have ratings and give you a good idea of how much force is being applied at different compression percentages. I don't have much access to the files at the moment but I think the force applied to a 1m x 1m area is close to 1 ton.

1

The brick mould needs the ribs. Without the ribs it will buldge out, but this is because the mould is not heated and the plastic will hit higher pressures during the extrusion/injection process. You're doing something different. My sheet press produces sheets of about 43cm x 43cm and I use about 200kg of pressure. Usually it's enough, sometimes I think a little more would be better. For your mould and size, it's a bit tricky. You'll have to just try and see what happens and make adjustments along the way. What you have going for you that is much different than industrial production is that you're heating the mould to melting temperatures. In doing so, you might not need the reinforcing ribs as the plastic will still flow so long as the temperature doesn't drop too low when compressing. Also, don't try to do 100% force too fast. Just compress it down and allow the plastic time to flow to where it needs to go. Too fast would increase the pressure on the mould and if not reinforced, it might buldge out. (edited)

1

Ben - Precious Plastic Ciledug

The brick mould needs the ribs. Without the ribs it will buldge out, but this is because the mould is not heated and the plastic will hit higher pressures during the extrusion/injection process. You're doing something different. My sheet press produces sheets of about 43cm x 43cm and I use about 200kg of pressure. Usually it's enough, sometimes I think a little more would be better. For your mould and size, it's a bit tricky. You'll have to just try and see what happens and make adjustments along the way. What you have going for you that is much different than industrial production is that you're heating the mould to melting temperatures. In doing so, you might not need the reinforcing ribs as the plastic will still flow so long as the temperature doesn't drop too low when compressing. Also, don't try to do 100% force too fast. Just compress it down and allow the plastic time to flow to where it needs to go. Too fast would increase the pressure on the mould and if not reinforced, it might buldge out. (edited)

Much appreciated reflection, Ben. In the end, success depends, beyond just preparation, on a willingness to "just try and see what happens".

Hi, I have started milling my own aluminium molds for my injection machine. What is the minimum thickness aluminium that u use to avoid the mold bending under the pressure of injection? I am thinking of using 20mm plate aluminium

Upcycler_Simon

Hi, I have started milling my own aluminium molds for my injection machine. What is the minimum thickness aluminium that u use to avoid the mold bending under the pressure of injection? I am thinking of using 20mm plate aluminium

a lot depends on how much force you can put out with your machine. 20mm is probably OK, you can clamp it into a vise if you need reinforcement on the outside of the mould

11:15 PM

we've used ~25.4mm in the past (50.8mm total thickness, each half is 25.4mm) and it's worked well

Christopher - Unmake Plastic

Reviewing the Brick Mold V4.0 page ( https://community.preciousplastic.com/how-to/brick-mould ), I can find no indication of material specifications! Preferred grade of steal- and, most importantly, thickness! Anybody know? Slots are cut at 5.5 wide... so... 5 mm? (edited)

@Precious Plastic can someone help here?

Marcela - Community Manager @ PP

@Precious Plastic can someone help here?

I have order one set from precious plastic barzar

Marcela - Community Manager @ PP

@Precious Plastic can someone help here?

Geoff indicated 5 mm.

It have 5.0mm

3:06 PM

Material i think it is SCxx and coating after laser cut

Marcela - Community Manager @ PP

@Precious Plastic can someone help here?

https://community.preciousplastic.com/how-to/brick-mould Step 4 explains the file name and thickness specifications. I think many people skip this part and start looking directly at the files.

Brick mould

Recycled plastic has the potential to replace more conventional and wasteful building materials such as hollow blocks. In this How-to, you will learn how to assemble the mould for the extruded plastic brick, ready for production. This brick was developed with the Extrusion Pro machine. Learn here how to build it:

Ben - Precious Plastic Ciledug

https://community.preciousplastic.com/how-to/brick-mould Step 4 explains the file name and thickness specifications. I think many people skip this part and start looking directly at the files.

In fairness, it would make a lot more sense to have that explanation in step 1 (fabrication) than step 4 (assembly). I don't think people "skip" that, I think they get stuck on step 1 and so never get to step 4?

2

@reSource Precious Plastics did you try to contact them directly? I met the guy last week on an event in France. Very cool and professional.

Christopher - Unmake Plastic

Reviewing the Brick Mold V4.0 page ( https://community.preciousplastic.com/how-to/brick-mould ), I can find no indication of material specifications! Preferred grade of steal- and, most importantly, thickness! Anybody know? Slots are cut at 5.5 wide... so... 5 mm? (edited)

1

Carolina

Click to see attachment 🖼️

Thanks, Caroline- just as Ben indicated, above, and reflecting affirmations by Geoff earlier. As Erik states, this instruction might be better placed at the outset/section 1.

Carolina

Click to see attachment 🖼️

Im which step Is mentioned the parts that need to be reinforced ? Or It isnt needed ?

Hélène

@reSource Precious Plastics did you try to contact them directly? I met the guy last week on an event in France. Very cool and professional.

They sorted it with me, very helpful and attentive. My plant pot game is mad now

Ruben

Im which step Is mentioned the parts that need to be reinforced ? Or It isnt needed ?

It's not specifically indicated in the instructions because it's part of the mould, just like a side piece for example. You'll be left with may regrets if you don't use the reinforcement ribs. I had a set of brick moulds made and they forgot to put the ribs on. After producing maybe 50pcs with the larger mould, I noticed that it's bulging out a bit on one side. All is not lost, with some persuasion with my sledge hammer and some welding, I can at least get it back to shape and install the ribs.

1

Ben - Precious Plastic Ciledug

It's not specifically indicated in the instructions because it's part of the mould, just like a side piece for example. You'll be left with may regrets if you don't use the reinforcement ribs. I had a set of brick moulds made and they forgot to put the ribs on. After producing maybe 50pcs with the larger mould, I noticed that it's bulging out a bit on one side. All is not lost, with some persuasion with my sledge hammer and some welding, I can at least get it back to shape and install the ribs.

Thank you Ben, i remember the case with your producer, about the guy that left...also going with your noozle recomendation

second shot with my pneumatic molder and @Rory - Sustainable Design Studio mold. 220c. sc100x300 pneumatic cylinder at 90psi. used the buster beagle mk3 clone.

2

another mold from @Rory - Sustainable Design Studio first try. its a bit tricky to remove from the mold, even when using silicone mold release. have to be very careful not to scratch the aluminum.

2

Butte (PP Philippines)

another mold from @Rory - Sustainable Design Studio first try. its a bit tricky to remove from the mold, even when using silicone mold release. have to be very careful not to scratch the aluminum.

I wonder- would polystyrene mold pics be useful? Plastic tools to make plastic parts...

Ruben

Thank you Ben, i remember the case with your producer, about the guy that left...also going with your noozle recomendation

Just want to follow up on the nozzle and make sure it's understood. Receiver - ~5cm ouside diameter with hole in middle Nut -Special because it's threaded to connect to the ~5cm piece but has a smaller diameter that rests on the nozzle when things get tightned. There's two ways I use my nozzle/screw style. For making bricks I use my system and have the receiver welded to the mould (5cm threaded piece with hole in middle). This is to keep a more solid and sealed connection between machine and mould. For making planks, I welded the recevier piece to steel plate. I make tabs on steel tubing and use vice grips to hold them together to the steel plate. This allows for quick connect/disconnect. If you need photos of this let me know. My internet connection isn't so great at the moment and im also on vacation

Butte (PP Philippines)

another mold from @Rory - Sustainable Design Studio first try. its a bit tricky to remove from the mold, even when using silicone mold release. have to be very careful not to scratch the aluminum.

Looks great! Maybe mess around with some things like the temperature or reduce the pressure and see if that helps. If you're using a hot mold, dont heat it up. Hopefully just messing with some of the settings will help sort out the releasing.

Butte (PP Philippines)

another mold from @Rory - Sustainable Design Studio first try. its a bit tricky to remove from the mold, even when using silicone mold release. have to be very careful not to scratch the aluminum.

Might mold temperature make a difference? (increasing shrink)

Christopher - Unmake Plastic

Might mold temperature make a difference? (increasing shrink)

Bingo

Ben - Precious Plastic Ciledug

Just want to follow up on the nozzle and make sure it's understood. Receiver - ~5cm ouside diameter with hole in middle Nut -Special because it's threaded to connect to the ~5cm piece but has a smaller diameter that rests on the nozzle when things get tightned. There's two ways I use my nozzle/screw style. For making bricks I use my system and have the receiver welded to the mould (5cm threaded piece with hole in middle). This is to keep a more solid and sealed connection between machine and mould. For making planks, I welded the recevier piece to steel plate. I make tabs on steel tubing and use vice grips to hold them together to the steel plate. This allows for quick connect/disconnect. If you need photos of this let me know. My internet connection isn't so great at the moment and im also on vacation

Did you weld the vice grips to the tabs or steal plate? They'd always be right where you need them... (who doesn't want pictures? Tell AND show, please!) (edited)

Christopher - Unmake Plastic

Did you weld the vice grips to the tabs or steal plate? They'd always be right where you need them... (who doesn't want pictures? Tell AND show, please!) (edited)

No need to weld the vice grips, that would just make it more difficult to position things. The method can fail if there's too much pressure or if you're having some issues with the mating surfaces not being flat enough or you cut the steel tubing not straight enough.

Ben - Precious Plastic Ciledug

No need to weld the vice grips, that would just make it more difficult to position things. The method can fail if there's too much pressure or if you're having some issues with the mating surfaces not being flat enough or you cut the steel tubing not straight enough.

Using my mental powers to spur a video illustration (can you feel it? soooo powerful)

1

Ben - Precious Plastic Ciledug

Looks great! Maybe mess around with some things like the temperature or reduce the pressure and see if that helps. If you're using a hot mold, dont heat it up. Hopefully just messing with some of the settings will help sort out the releasing.

we just needed to use a plastic putty knife. no metal on metal in the mold

Christopher - Unmake Plastic

Did you weld the vice grips to the tabs or steal plate? They'd always be right where you need them... (who doesn't want pictures? Tell AND show, please!) (edited)

been there done that... it works... kinda but the cheap brands wear out surprisingly fast.

Regarding designing molds for laser cutting, what sort of margins should be accounted for? Say, with edge finger joints or tabs and slots? Thanks in advance for your insight. (edited)

Geoff (PBI NTB)

Bench moulds done.

Nice! . I made some handles from a thin tube with some wood For easier handleling when hot

1

8:17 AM

Ruben

Nice! . I made some handles from a thin tube with some wood For easier handleling when hot

That's a great idea.

reSource Precious Plastics

Hiya guys , I’m having a real bother getting a good or even complete flower pot , I’m using a plasticprenur injection machine. My process so far is to heat the mold to 200C and use HDPE Flakes melted at 230C , but the plastic never flows all the way down the mold. Any help would be amazing.

Have you done It succesfully yet? Does It has enough space for air to go out? When mold Is totally clósed, if you blow inside of It, does air escapes?

Ruben

Click to see attachment 🖼️

Those look fantastic! For future iterations, consider incorporating a wider wooden disk at either end to prevent incidental contact with the metal ends. Were those stick welded ? (edited)

Christopher - Unmake Plastic

Those look fantastic! For future iterations, consider incorporating a wider wooden disk at either end to prevent incidental contact with the metal ends. Were those stick welded ? (edited)

Yes, at the moment I only had a small piece of metal tube to fit the broom stick, they were meant to be longer, just material availabity and budged did fit at the time, always room to improve versions And yes, stick welded,super thin tube so.. (edited)

Ruben

Nice! . I made some handles from a thin tube with some wood For easier handleling when hot

Do you have any recommendations for making moulds?

Andrés Romero

Do you have any recommendations for making moulds?

Yes i also need info about where to purchase eyeglasses mould?

11:36 AM

Any recommendation, asian area

Hello ! Is it possible to create injection molds at home with refractive cement ?

bababizdev

Hello ! Is it possible to create injection molds at home with refractive cement ?

Folks have had some success with 3d printed molds; I've also seen, believe it or not, plaster molds. These amount to limited use or waste molds. (edited)

1

We tried to make a compression mould from plaster and it didn't work, would take many many hours to heat (injection moulding is different)

1

bababizdev

Hello ! Is it possible to create injection molds at home with refractive cement ?

The other day I saw some epoxy resin moulds. They were using them more in a compression moulding manner, but I think it would be possible to use for injection moulding so long as you have a reinforced casing for it. I have used plaster of Paris in the past for casting plastic and was able to get some good details (could see finger prints in the results) but it was only good for one use as it broke. If you want to experiment, make sure to have some sort of casing to help contain and restrict any sort of flexing.

1

greetings company. I received complaints from a client that our benches get so hot in the sun that it is practically impossible to sit on them. Has anyone had a similar problem and maybe solved it in some way? thank you

I would propose him to paint the benches in white, it would not absorb the heat from sun

the benches are made of HDPE plastic and as far as I know no paint sticks to HDPE. Also according to my knowledge if we even manage to paint them white it will significantly reduce their lifespan as they will not be UV resistant.

aleksandarmasic92

the benches are made of HDPE plastic and as far as I know no paint sticks to HDPE. Also according to my knowledge if we even manage to paint them white it will significantly reduce their lifespan as they will not be UV resistant.

My understanding is HDPE may be "flame painted"- that is, the surface brushed with flame and paint applied. (not a testament or endorsement) Q: why would a top coat of paint impact the UV resistance of the underlying plastic? Any UV inhibitors and carbon black should be constituents of the plastic, if present, and would be no more impacted by paint than by being sat on by white slacks- what am I missing? An example of hot painting: https://www.youtube.com/watch?v=6Rc4LKMHC74 ...and here's an experiment with the application of plastic dissolved in solvent used as a primer for painting: https://www.youtube.com/watch?v=G-GwA70exjQ Explanations for why flame paining works has to do with changing the surface charge and oxidization, or so I am told- the important take away is heat is not the sole mechanism- that is, a heat gun is insufficient: ya gotta use a flame. (edited)

TheCrafsMan SteadyCraftin

Make PAINT stick to PLASTIC! (Flame Treatment) How to paint tricky ...

The DIY Science Guy

DIY plastic (polyethylene) primer

onlymoernobaut

Any recommendation, asian area

Hey, you can also directly ask for recommendations on Asia on the #🍜asia channel

aleksandarmasic92

the benches are made of HDPE plastic and as far as I know no paint sticks to HDPE. Also according to my knowledge if we even manage to paint them white it will significantly reduce their lifespan as they will not be UV resistant.

Titanium Dioxide as your UV protection instead of carbon?

1

aleksandarmasic92

the benches are made of HDPE plastic and as far as I know no paint sticks to HDPE. Also according to my knowledge if we even manage to paint them white it will significantly reduce their lifespan as they will not be UV resistant.

@waterppk got me off on a useful tangent- here's a topical study contrasting Titanium Dioxide and Carbon's UV protection. It's even got pictures: https://bioresources.cnr.ncsu.edu/resources/effects-of-carbon-black-and-titanium-dioxide-on-ultraviolet-weathering-of-wood-flour-hdpelumber-composites-using-multi-phase-co-extrusion-technology/ (edited)

Olivia Lenahan

Effects of carbon black and titanium dioxide on ultraviolet weather...

Hi all, I'd love to know if the injection molds for the geodesic dome project (https://community.preciousplastic.com/how-to/geodesic-dome-mould) are available for purchase. I'd love to construct a dome but don't have a CNC mill to make the injection molds. I haven't found them listed on the products catalog on Precious Plastic, but maybe someone here is willing to sell them to the US? Thank you in advance! (edited)

Geodesic dome mould

The Geodesic Dome is a lightweight structure using a minimum of materials. It is constructed by triangular elements, which are structurally rigid and splitting the stress evenly. Usually, it is used for greenhouses or temporary structures. Step 1-6: Prepare your components (1-2 days) Step 7-11: Assemble the structure (1-2 hours)

aleksandarmasic92

the benches are made of HDPE plastic and as far as I know no paint sticks to HDPE. Also according to my knowledge if we even manage to paint them white it will significantly reduce their lifespan as they will not be UV resistant.

i get spray paint to stick. Have to hit it with a hot air gun and fuse it on.

2:06 PM

example of painted HDPE

aleksandarmasic92

greetings company. I received complaints from a client that our benches get so hot in the sun that it is practically impossible to sit on them. Has anyone had a similar problem and maybe solved it in some way? thank you

I've never seen outdoor furniture that is black, I believe you've discovered the reason why.

I don't think there's an easy solution for your problem. Paint would be temporary as people would sit on the benches and the paint would wear off. My solution would be to make thin planks in a lighter color (white) and fix them to the top surfaces of the black beams. This way they won't absorb as much energy from the sun and should be much cooler. (edited)

Hello everybody, I’m still kinda new to all this and have some questions about making some molds for an injection molded prototype. I was thinking about 3d printing one out of resin bc its cheap and the part is complex. Do you think this would be my best option? (edited)

willsonsl

Hello everybody, I’m still kinda new to all this and have some questions about making some molds for an injection molded prototype. I was thinking about 3d printing one out of resin bc its cheap and the part is complex. Do you think this would be my best option? (edited)

I think it will work but it's difficult to say what the quality will be like. You might have some issues with the 3d printed mould if you rely on the strength of itself to hold together during injection. I'm not sure what to call it but it might be useful to have a strong box that holds The mould together. Something that will help keep the mould from expanding and blowing out when you inject. I've seen moulds made from epoxy resin, so it might work. I can't speak for the longevity, I've never used resin 3d printing and so I don't know how it responds to heat and pressure. Might be worth a shot? (edited)

willsonsl

Hello everybody, I’m still kinda new to all this and have some questions about making some molds for an injection molded prototype. I was thinking about 3d printing one out of resin bc its cheap and the part is complex. Do you think this would be my best option? (edited)

So much of this on YouTube. As Ben says, a bezel is used to provide needed support, and life spans are nothing like a metal mold. A couple of many, many examples, below. Keep in mind, you don't have to go the rout of machining your own supports, as there are off-the-shelf options, as demonstrated in the second video: https://www.youtube.com/watch?v=Zc7VSzVqlFE https://youtu.be/kq5dw1x05zI (edited)

Action BOX

We Made Plastic Injection Holders For Resin 3D Printed Molds | Home...

JohnSL - Random Products

3D Printed vs Aluminum Injection Molds

Christopher - Unmake Plastic

So much of this on YouTube. As Ben says, a bezel is used to provide needed support, and life spans are nothing like a metal mold. A couple of many, many examples, below. Keep in mind, you don't have to go the rout of machining your own supports, as there are off-the-shelf options, as demonstrated in the second video: https://www.youtube.com/watch?v=Zc7VSzVqlFE https://youtu.be/kq5dw1x05zI (edited)

I’ll definitely check it out thanks!!! (edited)

Ben - Precious Plastic Ciledug

I think it will work but it's difficult to say what the quality will be like. You might have some issues with the 3d printed mould if you rely on the strength of itself to hold together during injection. I'm not sure what to call it but it might be useful to have a strong box that holds The mould together. Something that will help keep the mould from expanding and blowing out when you inject. I've seen moulds made from epoxy resin, so it might work. I can't speak for the longevity, I've never used resin 3d printing and so I don't know how it responds to heat and pressure. Might be worth a shot? (edited)

I was talking w a friend and i think he might have mentioned something similar about the bezel(@Christopher - Unmake Plastic). I’ll do some@more research to find out about the properties of the resin.

Formlabs is providing useful documentation regarding 3d printed mould. The Rigid 10K Resin looks to work fine for this purpose. You can download a whitepaper after registration while following the second link. You will find CAD files for aluminium mould frames and interesting stuff as well while following the third link. https://formlabs.com/uk/applications/injection-molding/ https://3d.formlabs.com/injection-molding-with-3d-printed-molds-quick-start-guide/ https://www.injectionmolder.net/3d_printed_molds.html (edited)

2

willsonsl

Hello everybody, I’m still kinda new to all this and have some questions about making some molds for an injection molded prototype. I was thinking about 3d printing one out of resin bc its cheap and the part is complex. Do you think this would be my best option? (edited)

Here's some How-tos on 3D printing: https://community.preciousplastic.com/how-to/make-a-3d-printed-injection-mould https://community.preciousplastic.com/how-to/recycle-plastic-waste-into-3d-printing-filament

Make a 3D-printed injection mould

3D-printed molds are a great way to test highly detailed mold designs before investing in more expensive CNC-milled aluminum molds. 3D-printed molds can last for up to 100 shots, however results vary depending on variables like plastic temperature, injection pressure, and clamping method. A downside of 3D-printed molds is that they’re made from ...

Recycle plastic waste into 3d printing filament

In this how to we show you how you can recycle plastic waste into 3d printing filament. There are some things to watch out for and different machines needed to make for the best results. You can check out our How-To video here: https://youtu.be/IcmKFDxsUgA Feel free to visit our website :) https://www.qitech.de/en/industries

1

Does someone know anyone in the PP community who offers compression moulding on a bit larger scale? ~200-500pcs/month

Thomas Peterberns | Johannplasto

Yes, but that one you linked is not the original one. And I need the original dimensions.

Did you ever find the source for the stamps?

tomvb

Did you ever find the source for the stamps?

Sadly no:/ I‘m thinking to let produce some. I get in contact with the people who made them. How much do you need?

Thomas Peterberns | Johannplasto

Sadly no:/ I‘m thinking to let produce some. I get in contact with the people who made them. How much do you need?

Types 2, 4 and 5, just one of each

9:36 AM

I’m looking at an aliexpress seller that can make custom brass stamps with a m5 screw hole, quite cheap

9:37 AM

https://a.aliexpress.com/_EG8M55V

tomvb

I’m looking at an aliexpress seller that can make custom brass stamps with a m5 screw hole, quite cheap

Your link doesn't work. Can you share an image of what you want them to look like and what size you want them to be? I recall seeing these, I have a fiber laser that might be able to etch them or a CNC mill set up to do rounds that might work as well. I need to make some for ourselves

waterppk

Your link doesn't work. Can you share an image of what you want them to look like and what size you want them to be? I recall seeing these, I have a fiber laser that might be able to etch them or a CNC mill set up to do rounds that might work as well. I need to make some for ourselves

https://nl.aliexpress.com/item/32390391825.html does this link work?

11:22 AM

I think that 2x2cm would work best

tomvb

https://nl.aliexpress.com/item/32390391825.html does this link work?

Link works for me, I have the app installed and it opens right up.

tomvb

https://nl.aliexpress.com/item/32390391825.html does this link work?

That link works, for that price you should order one

Included here are some pics of the press mold I'm working on. It's designed to be heated in a salvaged household convection oven, maximizing the use of that space, producing an annealed billet for machining- about 75-80lbs of HDPE, and around 14.5" x 8.815" x 20.75", before any shrinkage. Die springs maintain compression while soaking; the mold will needs be slid out periodically for re-torquing of the nuts compressing the springs. The mold itself weighs in near 200lbs, and will require apparatus for handling; the entire assembly, oven and all, will be elevated on a wheeled frame to the height of my shop table and CNC. The mold sides disassemble to access the cooled billet. The springs collectively can deliver over 3000 lbs. The horizontal wall on the plug lid is positioned with a quarter inch of clearance, providing evacuation rout for air, excess plastic, until fully compressed, the plug flange pressed into contact with the mold top flange. There are a number of design choices in service to the use of space, handling, weight, and rigidity; other designs considered included localizing the load to the top flanges, allowing for shorter acme screws- in such a version, nut clearance would compete for space with the billet, shaving off another 1 inch of width. Questions and feedback are welcome. (edited)

1

looks cool, what are you making with the plastic brick?

waterppk

looks cool, what are you making with the plastic brick?

Sculpture constituents- eventually. I aim to sequester around 4k lbs in as many as 140 relief carved bricks.

Christopher - Unmake Plastic

Included here are some pics of the press mold I'm working on. It's designed to be heated in a salvaged household convection oven, maximizing the use of that space, producing an annealed billet for machining- about 75-80lbs of HDPE, and around 14.5" x 8.815" x 20.75", before any shrinkage. Die springs maintain compression while soaking; the mold will needs be slid out periodically for re-torquing of the nuts compressing the springs. The mold itself weighs in near 200lbs, and will require apparatus for handling; the entire assembly, oven and all, will be elevated on a wheeled frame to the height of my shop table and CNC. The mold sides disassemble to access the cooled billet. The springs collectively can deliver over 3000 lbs. The horizontal wall on the plug lid is positioned with a quarter inch of clearance, providing evacuation rout for air, excess plastic, until fully compressed, the plug flange pressed into contact with the mold top flange. There are a number of design choices in service to the use of space, handling, weight, and rigidity; other designs considered included localizing the load to the top flanges, allowing for shorter acme screws- in such a version, nut clearance would compete for space with the billet, shaving off another 1 inch of width. Questions and feedback are welcome. (edited)

I had some civil engineering students do something like this but without the compression. Ended up with nearly 6" x 6" x 6" cube (15cm x 15cm x 15cm). Compression will help with many issues but you'll probably have a difficult time with cooling due to it being so thick. The center will stay hot for a long time and as the outer parts of the plastic block cool it will compress on the hot core. Realistically you can only compress on opposing sides, so this leaves 4 sides for uneven/wonky/eruptions (hot plastic in the center can potentially push out). My advise is to not make a solid block of plastic. But if you want a solid block, just be prepared for some challenges. You will likely need to cut the sides to make them flat and you also may have some trapped air bubbles. https://www.instagram.com/p/B8aL52dgUz9/?igshid=MzRlODBiNWFlZA==

preciousplasticciledug

Here's the result from the previous post. It's HDPE and gravel. There's some cracking on the sides where the gravel is very close to it as the plastic shrinks when it cools. Mould size is 15cm x 15cm x 15cm Total shrinkage is about 5mm all around after plastic has cooled off. #preciousplastic #preciousplasticindonesia

Likes

178

1

2:09 AM

Here's some photos of one block with trimmed sides. They didn't use compression but did periodically insert plastic to help alleviate any sort of trapped air issues...didnt quite work. There's also rocks that sank to the bottom. They were doing this in the name of science, trying to figure out if it's worth doing and how strong it is.

2

"... you'll probably have a difficult time with cooling due to it being so thick." I'm counting on it- I project a heat-melt-anneal-cool schedule of (at least) 48 hours. Progressive heating, progressive cooling, with a massy mold acting as capacitor. Once the mold is fully compressed, flanges pressed together, we will have a demonstration testing Pascal's notions about pressure distribution! That said, I plan to lose up to 4% to shrinkage and irregularities on the faces, +planing flat. As to voids, I have no doubt it will take time to dial in the temperature, pressure, and soak times; the example given by the folks at Recycle Studio in Costa Rica impressed the importance of progressive, periodic application of pressure to minimize voids- and the springs I've sourced should allow heating up to 250 C, if necessary. What I don't want to have to do is compress in layers, waiting for the press to cool between each before adding more plastic, heating back up again- what a nightmare that would be! In such a circumstance, I'd probably end up building several short-slab presses, combining the product in the large press- let's hope I've lived better than that! (edited)

Christopher - Unmake Plastic

"... you'll probably have a difficult time with cooling due to it being so thick." I'm counting on it- I project a heat-melt-anneal-cool schedule of (at least) 48 hours. Progressive heating, progressive cooling, with a massy mold acting as capacitor. Once the mold is fully compressed, flanges pressed together, we will have a demonstration testing Pascal's notions about pressure distribution! That said, I plan to lose up to 4% to shrinkage and irregularities on the faces, +planing flat. As to voids, I have no doubt it will take time to dial in the temperature, pressure, and soak times; the example given by the folks at Recycle Studio in Costa Rica impressed the importance of progressive, periodic application of pressure to minimize voids- and the springs I've sourced should allow heating up to 250 C, if necessary. What I don't want to have to do is compress in layers, waiting for the press to cool between each before adding more plastic, heating back up again- what a nightmare that would be! In such a circumstance, I'd probably end up building several short-slab presses, combining the product in the large press- let's hope I've lived better than that! (edited)

The layering helped things melt down without trapping a bunch of air, but they still had some trapped air anyways. Sounds like you know what to expect. Gradually cooling should be a big help but I feel 250C is a bit risky as at that temperature the material will start breaking down and it will stick to your mould and give you a headache. Start off with 200c max... Gonna take ages anyways to heat up all that mass

Ben - Precious Plastic Ciledug

The layering helped things melt down without trapping a bunch of air, but they still had some trapped air anyways. Sounds like you know what to expect. Gradually cooling should be a big help but I feel 250C is a bit risky as at that temperature the material will start breaking down and it will stick to your mould and give you a headache. Start off with 200c max... Gonna take ages anyways to heat up all that mass

"Gonna take ages anyways to heat up all that mass" I wish it would take longer- reached 39c here, yesterday.

1

Christopher - Unmake Plastic

"Gonna take ages anyways to heat up all that mass" I wish it would take longer- reached 39c here, yesterday.

37+ here, working on the lathe isn't funny... Fortunately I have two weeks left to go on vacation... I hope in northern France I can find lower temperatures...

1

Davide->PreciousPlasticRomagna

37+ here, working on the lathe isn't funny... Fortunately I have two weeks left to go on vacation... I hope in northern France I can find lower temperatures...

Aren't the air conditioners in France on strike again?

(edited)

1

Christopher - Unmake Plastic

Aren't the air conditioners in France on strike again?

(edited)

I didn't know, I'm used to carry my wheeled 8sq. meter home attached to my old swedish green friend during vacations... Never had a conditioner inside it, maybe an hair conditioner....

Davide->PreciousPlasticRomagna

I didn't know, I'm used to carry my wheeled 8sq. meter home attached to my old swedish green friend during vacations... Never had a conditioner inside it, maybe an hair conditioner....

Uncool, dude- even if they are Swedish. (fun with lost-in-translation puns) (edited)

Please tell me what's fun, I need to improve my English (and since I'm a sarcastic one I want to laugh at my errors!)

3:36 PM

I was sarcastic taking seriously the air conditioners strike, if it isn't clear enough...

Davide->PreciousPlasticRomagna

I was sarcastic taking seriously the air conditioners strike, if it isn't clear enough...

"....attached to my old swedish green friend" I used "uncool" to mean "not OK"- instead of relative temperature -in an exchange focusing on temperature. After searching the web for references to a "Swedish Green Friend" and finding nothing applicable, I decided a literal interpretation would offer the most levity- that you use an old, Swedish environmentalist as your beast of burden. Bonus mirth: the suggestions that being a Swede carries some sort of stigma ("even if they are Swedish") (edited)

Ben - Precious Plastic Ciledug

Here's some photos of one block with trimmed sides. They didn't use compression but did periodically insert plastic to help alleviate any sort of trapped air issues...didnt quite work. There's also rocks that sank to the bottom. They were doing this in the name of science, trying to figure out if it's worth doing and how strong it is.

(BTW: I had gleaned the block press images from your Instagram in my early research!) (edited)

Christopher - Unmake Plastic

"....attached to my old swedish green friend" I used "uncool" to mean "not OK"- instead of relative temperature -in an exchange focusing on temperature. After searching the web for references to a "Swedish Green Friend" and finding nothing applicable, I decided a literal interpretation would offer the most levity- that you use an old, Swedish environmentalist as your beast of burden. Bonus mirth: the suggestions that being a Swede carries some sort of stigma ("even if they are Swedish") (edited)

No man, I was joking about the age of my car, I own a 1997 Volvo S40 fitted with a LPG system, he's Swedish (not completely, but mainly) and green... I say "he" because it's a car, but seeing the shape and dimensions of the "thing" on which I hook the caravan to tow it around Europe, doesn't seem too female...

3

Made a simple keychain mould for an upcoming event in our neighborhood. Going to set up a drill press that's been modified into an injection moulder and invite kids to make their own keychains

waterppk

Made a simple keychain mould for an upcoming event in our neighborhood. Going to set up a drill press that's been modified into an injection moulder and invite kids to make their own keychains

Nice! How quick do you anticipate the injector cycling? (how long of a line of kids will there be?) (edited)

lol, there's gonna be a long line

9:50 PM

I'm making two more moulds so we can speed up the changeover time. The mould is just clamped together with a c clamp and we use the nose of the injector on the drill press to align things

waterppk

Made a simple keychain mould for an upcoming event in our neighborhood. Going to set up a drill press that's been modified into an injection moulder and invite kids to make their own keychains

For the sake of sanity and saving time, have you considered making a mould that produces more than one keychain per cycle?

2:21 AM

For example, carabiners... I've seen moulds for 1 per cycle and 6 per cycle. It's quite satisfying to get 6 in one cycle.

Too low of shot volume, also going to have kids pulling the handle they don't understand how to really hammer the plastic in there for a multipart mould

2:51 AM

here's the moulder: https://photos.app.goo.gl/H3ujSiHvFwgADV3h6 it's an old drill press with a solid rod in the chuck. That rod presses through a cylinder with 2 heater cartridges and a thermocouple connected to a PID controller. Gives about a thumb sized shot volume, if you really lean on the handle you can pretty easily spread a mould with a pair of C-clamps on it. (Edit: Click "open in browser" to see images) (edited)

waterppk

here's the moulder: https://photos.app.goo.gl/H3ujSiHvFwgADV3h6 it's an old drill press with a solid rod in the chuck. That rod presses through a cylinder with 2 heater cartridges and a thermocouple connected to a PID controller. Gives about a thumb sized shot volume, if you really lean on the handle you can pretty easily spread a mould with a pair of C-clamps on it. (Edit: Click "open in browser" to see images) (edited)

Woah! Wasn't expecting that! I see your shot size problem now haha

1

I need help here, I’m designing a mold but I really don’t know the diameter of the sprue. There is a reduction but would like to know what are your recommendations. Additionally anyone has experimented with the runner? What diameter did you use? Thanks!

Kristoff

I need help here, I’m designing a mold but I really don’t know the diameter of the sprue. There is a reduction but would like to know what are your recommendations. Additionally anyone has experimented with the runner? What diameter did you use? Thanks!

I think your moulder capability is probably as/more important than your mould design. If you have a high pressure machine with a heated mould you can push plastic a lot farther than an unheated mould at low pressures

Kristoff

I need help here, I’m designing a mold but I really don’t know the diameter of the sprue. There is a reduction but would like to know what are your recommendations. Additionally anyone has experimented with the runner? What diameter did you use? Thanks!

Fusion 360 includes a plastic injection simulator exactly because mold variations makes certainty a dubious prospect. Lacking experience, we are left with trial and error. Were I you, I would prepare comprehensive illustrations of your mold design along with specs for your injector's capacity, and post this question again- here, for my benefit, but also at one of the plastic injection forums (there are entire communities dedicated to injection molding). I've been reading a board over on Reddit that seems to be populated by industry professionals- you can find it here: https://www.reddit.com/r/InjectionMolding/

r/InjectionMolding

waterppk

I think your moulder capability is probably as/more important than your mould design. If you have a high pressure machine with a heated mould you can push plastic a lot farther than an unheated mould at low pressures

Exactly. For example, with ~450bar plastic injection I'm using ~1mm gate with 4mm runner for the seahorse mold, but if I lower the injection pressure around 270bar the mold should be hot, or the plastic become stuck in the gate.

hi brains-trust. I am having a problem with HDPE coasters coming out of my injection mold with a concave surface on one side. The other side is nice and flat. I am confident that the mold is not bent as I only milled it today out of 20mm aluminium. When I look at the product that comes out of the mold it almost looks like the outside edges are shrinking but it isn't shrinking in the middle which is what causes the concave surface. Has anyone encountered this issue and if so, how did you resolve it? (edited)

if your sprue/gate is feeding into the center that area may be taking longer to cool. Are you keeping the mould closed for a while after filling? Consider waiting longer as trial, or cooling it with water/air to freeze the gate. Might be hard to get a mass of plastic that large to cool evenly without cooling the mould to keep it flat

1

Upcycler_Simon

hi brains-trust. I am having a problem with HDPE coasters coming out of my injection mold with a concave surface on one side. The other side is nice and flat. I am confident that the mold is not bent as I only milled it today out of 20mm aluminium. When I look at the product that comes out of the mold it almost looks like the outside edges are shrinking but it isn't shrinking in the middle which is what causes the concave surface. Has anyone encountered this issue and if so, how did you resolve it? (edited)

I had the issue on the first hexagonal tiles made, in my case I solved it rising the injection pressure a little and maintaining the pressure after the complete fill for 5 seconds. Seems that especially HDPE has a high shrinking rate, so if you don't keep the injection pressure until the majority of the injected material freezes, the shrinkage happens in the hotter area, just under the gate.

4

waterppk

here's the moulder: https://photos.app.goo.gl/H3ujSiHvFwgADV3h6 it's an old drill press with a solid rod in the chuck. That rod presses through a cylinder with 2 heater cartridges and a thermocouple connected to a PID controller. Gives about a thumb sized shot volume, if you really lean on the handle you can pretty easily spread a mould with a pair of C-clamps on it. (Edit: Click "open in browser" to see images) (edited)

thats the old Gingery solution. good stuff...

1

3:20 AM

https://www.youtube.com/watch?v=hvJil9lilE0

Scorch Works

Plastic Injection molding a fishing lure using a Gingery plastic in...

has anybody made 3d printed injection molds?

tonelessbod

has anybody made 3d printed injection molds?

there are videos on the one army youtube from a couple years ago. they also make laser engraved acrylic molds

Butte (PP Philippines)

there are videos on the one army youtube from a couple years ago. they also make laser engraved acrylic molds

I looked and couldnt find anything, happen to have a link?

https://community.preciousplastic.com/how-to/make-a-3d-printed-injection-mould

Make a 3D-printed injection mould

3D-printed molds are a great way to test highly detailed mold designs before investing in more expensive CNC-milled aluminum molds. 3D-printed molds can last for up to 100 shots, however results vary depending on variables like plastic temperature, injection pressure, and clamping method. A downside of 3D-printed molds is that they’re made from ...

Erik72

https://community.preciousplastic.com/how-to/make-a-3d-printed-injection-mould

thank you!

1

Davide->PreciousPlasticRomagna

I had the issue on the first hexagonal tiles made, in my case I solved it rising the injection pressure a little and maintaining the pressure after the complete fill for 5 seconds. Seems that especially HDPE has a high shrinking rate, so if you don't keep the injection pressure until the majority of the injected material freezes, the shrinkage happens in the hotter area, just under the gate.

"I solved it rising the injection pressure a little and maintaining the pressure after the complete fill for 5 seconds." "Seems that especially HDPE has a high shrinking rate, so if you don't keep the injection pressure until the majority of the injected material freezes, the shrinkage happens in the hotter area, just under the gate." As the HDPE cools, the portion that organizes into crystalline structures becomes more compact; the thicker the part, the more material available to organization shrinkage. As I understand it, as Davide says, keeping up the pressure and temperature control can makes a significant difference. You can really impact the density and character of the part, too. Paradoxically, injection professionals will use the crystallization structures to help maintain shape and control shrinkage by actively cooling their molds, locking in the surface geometry; this also constricts the gate aperture, increasing the pressure of the material injected past the constriction in the same way as pressing your finger over the end of a garden hose. Of course, cooling the mold requires injection temperatures and pressures exceed a necessary threshold- that might just not be possible for everybody. Cooling the mold in this way also imparts stress into the part- which may be good, depending on the qualities sought, @Upcycler_Simon . (edited)

2

Christopher - Unmake Plastic

"I solved it rising the injection pressure a little and maintaining the pressure after the complete fill for 5 seconds." "Seems that especially HDPE has a high shrinking rate, so if you don't keep the injection pressure until the majority of the injected material freezes, the shrinkage happens in the hotter area, just under the gate." As the HDPE cools, the portion that organizes into crystalline structures becomes more compact; the thicker the part, the more material available to organization shrinkage. As I understand it, as Davide says, keeping up the pressure and temperature control can makes a significant difference. You can really impact the density and character of the part, too. Paradoxically, injection professionals will use the crystallization structures to help maintain shape and control shrinkage by actively cooling their molds, locking in the surface geometry; this also constricts the gate aperture, increasing the pressure of the material injected past the constriction in the same way as pressing your finger over the end of a garden hose. Of course, cooling the mold requires injection temperatures and pressures exceed a necessary threshold- that might just not be possible for everybody. Cooling the mold in this way also imparts stress into the part- which may be good, depending on the qualities sought, @Upcycler_Simon . (edited)

Yes, exactly. Even with the small seahorse if I don't keep the pressure for at least 3/4" they tend to deform in the thicker zone. They are 3grams parts, with the thicker part around 11mm. I'm injecting them at around 500 bar, the mold is thick and so it keeps heat, the first ones I have to keep the pressure a little bit higher, around 600 bar, and when the mold became hot I can lower it a little. The gate on that mold is ~1mm, the runner is 4mm, I started with a 0.8mm gate but it is too small, so I enlarged it a bit with a round file (the one used by mold makers, I have a couple of them from the good old times in when I was messing with two stroke engines...

).

1

Hi all, I just wanted to recommend someone who just did some 3D drawings for some moulds. He has done an awesome job , attention to detail outstanding. His name is Sergio, if you need 3D drawings for injection moulds. He is the guy. You can find him on Upwork. https://www.upwork.com/fl/~017f8ed7eb3ad6845a

Upwork Freelancer

Upwork Freelancer Profile includes information about skills, work experience and samples of work.

3

has anyone used acrylic to make injection mold plastes and for compression molding ?

Alex_recycles and creates

has anyone used acrylic to make injection mold plastes and for compression molding ?

I made some mistakes but I made an acrylic mould for injection that would be sandwiched between two plates of steel. My observation is that the acrylic will melt a little bit during each use. If you dont make the acrylic thick or strong enough, it will crack and plastic will push out. It feels like a waste so I don't recommend it.

Sunday in a used market I found molds from a '90s toy, after some research I found that in the USA the same toy concept was sold as "creepy crawler" or "thingsmaker" since the '60s. It's a thin mold (I think made from zinc alloy "Zamak"), so I reinforced it with epoxy, then I flattened the mold surface with an oil stone, the epoxy side was milled flat and I made a small mold holder. Seems working well, yesterday I made some test. This is white blow molding HDPE, injected at around 80bar. Some pics!

1

10:05 AM

10:06 AM

10:07 AM

If someone want to use them in the states, there's plenty of "creepy crawlers" molds on the web.

lol, that's not a creepy child form at all

1

6:57 PM

very cool you were able to reinforce the back solid

1

Davide->PreciousPlasticRomagna

Sunday in a used market I found molds from a '90s toy, after some research I found that in the USA the same toy concept was sold as "creepy crawler" or "thingsmaker" since the '60s. It's a thin mold (I think made from zinc alloy "Zamak"), so I reinforced it with epoxy, then I flattened the mold surface with an oil stone, the epoxy side was milled flat and I made a small mold holder. Seems working well, yesterday I made some test. This is white blow molding HDPE, injected at around 80bar. Some pics!

How well does the zamak hold up? I've thought about casting zamak/zinc to make molds for plastic.

1

JohnNephew

How well does the zamak hold up? I've thought about casting zamak/zinc to make molds for plastic.

I can't say, I made just a test for now. Seems holding well, however. But there's a block of resin all around, so the zamak is working mainly as a surface, leaving the mechanical stress to the resin. We'll see if heat is going to do some damage...hope not.

1

Has anyone here made aluminum molds using sand casting ? This would be for making compressed molds

Alex_recycles and creates

Has anyone here made aluminum molds using sand casting ? This would be for making compressed molds

Nope, but this sounds really cool, watched alot of video's on lost PLA.

Alex_recycles and creates

Has anyone here made aluminum molds using sand casting ? This would be for making compressed molds

I have done some experiments with sand casting aluminum, zinc, and bronze. One thing I've done is to cast solid plugs to fit in the end of cut-off steel pipe to use for compression molding cylindrical turning blanks (such as these https://bazar.preciousplastic.com/raw-material/beams/composite-cylindrical-turning-blanks-3-diameter/)

4:15 PM

Obviously this isn't making a finely detailed mold or anything, but steel pipe can hold a lot of pressure; I can make multiple plugs and stack them as necessary inside the pipe; and it is way superior to the lifespan of compression molds I had first tried making out of plywood and the like.

4:20 PM

(Maybe we should make a how-to/video of this whole process?)

Im also talking about sheet press molding

For the basic "make plastic turning blanks for your wood lathe" what you need are: 1. A foundry/furnace & gear (crucible, tongs, safety gear) for melting metal. There are loads of how-tos on doing this from scratch, even with wood fuel, or you can buy a set somewhere like Amazon for $120 to $200 with everything you need except a propane tank. 2. Scrap metal. Aluminum cans can work, but they result in a lot of dross due to linings, labels, inks, etc. Dead hard drives have some nice big hunks of aluminum. You may also find cheap or free scraps and cut-offs from local scrap dealers, machine shops, metal suppliers, etc. Or watch for things like people throwing out aluminum-frame outdoor furniture that has bent or broken. (Alternative scrap metals like zinc/zamak may work and have considerably lower melting points, making the whole process faster and less energy intensive.) 3. Steel pipe of whatever shape or diameter you want or can simply find. We have a metal supplier next door who has a cut-offs bin with all the steel scrap at 50 cents per pound, so that has been a great place to find things like a 3" diameter round steel pipe 6" long. Liquid metal is poured in the pipe, where it solidifies into a fitting plug. Make one for either end, and voila, you have a cylindrical compresion mold.

4:40 PM

4. Scrap plastic. HDPE is ideal for various reasons. There are lots of permutations for the shape of the plastic (film/sheet, shred, pellets, intact caps, whatever) that affect the output, but that's all for experimental fun. 5. A way to melt the plastic. We have an assortment of George Foreman Grills and sandwich presses found at garage sales and thrift stores for about $5 each. Foreman Grills seem to target about 350 F as a consistent temperature, which is good for melting HDPE without burning. Some people really like using teflon sheets to keep the grill surfaces clean. 6. Silicone oven/grill mitts for handling the hot plastic, kneading out bubbles, and twisting the putty-like heated plastic for patterns you desire 7. A way to apply pressure to the two plugged ends of the mold after hot plastic is put between them. I like using a 12 ton shop press ($150 to $200), but there are lots of other ways to do it.

experiment with scrap polyester fabric and PP plastic in the sheet press.

2

Another "creepy crawlers" style mold arrived yesterday, and a lot more are on the way...

7:45 PM

7:48 PM

Did someone have suggestions on cheap epoxy putty to fill the back of the mold to reinforce it? The "sticks" I used for the first two tests are expensive (I needed 3 sticks and they're 10€ each).

JB Weld in large containers should withstand the temps you're at and have plenty of "solids" to resist compression (https://www.jbweld.com/product/j-b-weld-professional-size) . You could blend sand or something else to take up mass in the epoxy since you don't need glue as much as grout

J-B Weld Professional Size

J-B Weld is The Original Cold Weld two-part epoxy system that provides strong, lasting repairs to metal and multiple surfaces.

waterppk

JB Weld in large containers should withstand the temps you're at and have plenty of "solids" to resist compression (https://www.jbweld.com/product/j-b-weld-professional-size) . You could blend sand or something else to take up mass in the epoxy since you don't need glue as much as grout

Unfortunately it isn't a make sold in Italy, and from the US shipping cost more than the product...

Davide->PreciousPlasticRomagna

Unfortunately it isn't a make sold in Italy, and from the US shipping cost more than the product...

Just use regular epoxy and use clean dry sand or something low expansion like mortar/grout as a filler, it'll bulk up the glue volume alot and not shrink

waterppk

Just use regular epoxy and use clean dry sand or something low expansion like mortar/grout as a filler, it'll bulk up the glue volume alot and not shrink

Today I found the right one! It's an epoxy putty used for moped two stroke tuning (I don't know there, here in Italy we have a 50cc limitation for moped, so there is a huge maket for tuning parts), it's made to fill the crankcase external in the area where there's not enough material to enlarge engine transfers. It's advertised for 80MPa compression strength, high temperature (200°C) and to have a maximum shrinkage during hardening of 0.005%. It is also resistant to chemicals, that's a plus and it means that I can use the oil stone to flatten the mold face without fear of damaging it. 66.90€ for 800g shipping included, so it isn't bad.

Davide->PreciousPlasticRomagna

Today I found the right one! It's an epoxy putty used for moped two stroke tuning (I don't know there, here in Italy we have a 50cc limitation for moped, so there is a huge maket for tuning parts), it's made to fill the crankcase external in the area where there's not enough material to enlarge engine transfers. It's advertised for 80MPa compression strength, high temperature (200°C) and to have a maximum shrinkage during hardening of 0.005%. It is also resistant to chemicals, that's a plus and it means that I can use the oil stone to flatten the mold face without fear of damaging it. 66.90€ for 800g shipping included, so it isn't bad.

We have the same moped law in the US, I'm near a college campus there's quite a few students who stretch the definition of 50cc's

1

waterppk

We have the same moped law in the US, I'm near a college campus there's quite a few students who stretch the definition of 50cc's

Now I'm 42 and I have a 2007 Kawasaki ER6N, but during the good old times when I was younger I had a Malaguti Fifty (meant to have 1.5hp and making top speed 45km/h) that was heavily tuned, with the right carburator, a 72cc cylinder, the right expansion exhaust, reed valve and with a lot of blueprinting was capable of reaching up to 130km/h (GPS data, not from the optimistic original tachometer!), doing wheelies from pure acceleration in 2nd gear and was capable, during the first tests in the garages underground tunnel of the terrace house of my parents, so I'm speaking of a stretch of 100m concrete tunnel with walls at the ends, to start, reaching 70km/h and stopping obviously before crashing in the wall... Stupid things I do when I was young... But it was funny as hell!

5:13 PM

It was the same model and colour...

2

Hello everyone! I had a question to see if anyone had the same issue and whether they knew how to fix it

6:22 PM

We have the classic manual injection machine from PP, and we have a problem that sometimes the plastic is coming out of the top cavityu at insanely hot temperatures

6:24 PM

FYI for a method to feed sachet and fluff plastic to your extrusion

1

waterppk

Just use regular epoxy and use clean dry sand or something low expansion like mortar/grout as a filler, it'll bulk up the glue volume alot and not shrink

Resin arrived earlier than expected. In next weeks all the molds I bought must arrive, but next week I'm on vacation, so I start making something later.

Alberto

We have the classic manual injection machine from PP, and we have a problem that sometimes the plastic is coming out of the top cavityu at insanely hot temperatures

Is the nozzle getting clogged so the plastic has nowhere but upwards to go? Otherwise are you increasing the plastic temperature towards the nozzle - maybe you're liquifying plastic near the top by running it too hot?

1

waterppk

Is the nozzle getting clogged so the plastic has nowhere but upwards to go? Otherwise are you increasing the plastic temperature towards the nozzle - maybe you're liquifying plastic near the top by running it too hot?

or waiting too long between shots (edited)

Has anyone combined two materials in an injection mould. Eg :Plastics and metal. Looking to have a solid material in the mould and inject plastic in and fuse both. Thank you

RILA

Has anyone combined two materials in an injection mould. Eg :Plastics and metal. Looking to have a solid material in the mould and inject plastic in and fuse both. Thank you

That's called overmoulding, that's a common thing in industry (tool grips are rubber overmoulded on plastic, screwdrivers are plastic handles overmoulded on the metal screwdriver bit)

RILA

Has anyone combined two materials in an injection mould. Eg :Plastics and metal. Looking to have a solid material in the mould and inject plastic in and fuse both. Thank you

Obviously if you inject in a mold in which there's a metal part, the metal part comes out embedded in the plastic, not fused together. I'm planning to put threaded inserts in some parts (for example in knobs) or small magnets, but I never tried yet. However it's a common practice.

waterppk

That's called overmoulding, that's a common thing in industry (tool grips are rubber overmoulded on plastic, screwdrivers are plastic handles overmoulded on the metal screwdriver bit)

Appreciate the reply.

Davide->PreciousPlasticRomagna

Obviously if you inject in a mold in which there's a metal part, the metal part comes out embedded in the plastic, not fused together. I'm planning to put threaded inserts in some parts (for example in knobs) or small magnets, but I never tried yet. However it's a common practice.

Thanks for the Reply - threaded insert is a nice idea. If my metal cap has a hollow center I’m thinking it would allow the plastic in and embed and create a Steamline piece (edited)

RILA

Has anyone combined two materials in an injection mould. Eg :Plastics and metal. Looking to have a solid material in the mould and inject plastic in and fuse both. Thank you

I have taken rare earth magnets and dropped them in the mold, then injected/overmolded with plastic. It works really well, the only issue you might have with magnets is that heat can cause them to lose their magnetism. The specific material of your magnet combined with the level of heat (and I'm pretty sure the length of applied heat matters also?) its all going to determine how much magnetism gets lost, so do some experimenting before you rush to a final solution.

Erik72

I have taken rare earth magnets and dropped them in the mold, then injected/overmolded with plastic. It works really well, the only issue you might have with magnets is that heat can cause them to lose their magnetism. The specific material of your magnet combined with the level of heat (and I'm pretty sure the length of applied heat matters also?) its all going to determine how much magnetism gets lost, so do some experimenting before you rush to a final solution.

I'm also thinking about that, if you scroll up you can find some toy molds I found and adapted to injection, now I bought some with different shapes and I'm wondering about making fridge magnets from them, maybe ferrite magnets are a better choice since they withstand higher temperatures, I have to try making steel mold holders for them, to have the magnets locked in the right place during injection.

Davide->PreciousPlasticRomagna

I'm also thinking about that, if you scroll up you can find some toy molds I found and adapted to injection, now I bought some with different shapes and I'm wondering about making fridge magnets from them, maybe ferrite magnets are a better choice since they withstand higher temperatures, I have to try making steel mold holders for them, to have the magnets locked in the right place during injection.

https://en.wikipedia.org/wiki/Curie_temperature

Curie temperature

In physics and materials science, the Curie temperature (TC), or Curie point, is the temperature above which certain materials lose their permanent magnetic properties, which can (in most cases) be replaced by induced magnetism. The Curie temperature is named after Pierre Curie, who showed that magnetism was lost at a critical temperature.The fo...

waterppk

https://en.wikipedia.org/wiki/Curie_temperature

Yes, I read about it. The main question is what's the temperature the magnet is experiencing, since it is attached to a flat cold metal surface and the plastic is going to cool rapidly. Probably it can reach up to the average temperature of the plastic and the mold.

Hi all, has anyone used alumimun instead of steel for the mould frames in sheet press? I am thinking of making them out of aluminum to decrease the weight but cant be sure

Cochon

Hi all, has anyone used alumimun instead of steel for the mould frames in sheet press? I am thinking of making them out of aluminum to decrease the weight but cant be sure

They'd just be substantially more expensive, also harder to weld if you don't have the experience/equipment. You'll probably want to make the members thicker to keep the same rigidity but it depends on whether the frames are overbuilt to start with or not

1

Hi all! Does anyone know how I can get in contact with the designers of the geodesic dome mold? https://community.preciousplastic.com/how-to/geodesic-dome-mould

Geodesic dome mould

The Geodesic Dome is a lightweight structure using a minimum of materials. It is constructed by triangular elements, which are structurally rigid and splitting the stress evenly. Usually, it is used for greenhouses or temporary structures. Step 1-6: Prepare your components (1-2 days) Step 7-11: Assemble the structure (1-2 hours)

Paloma17

Hi all! Does anyone know how I can get in contact with the designers of the geodesic dome mold? https://community.preciousplastic.com/how-to/geodesic-dome-mould

@PP Team can anybody help here?

It was @Kit

RILA

Has anyone combined two materials in an injection mould. Eg :Plastics and metal. Looking to have a solid material in the mould and inject plastic in and fuse both. Thank you

this is called over molding. very common. we do it for making chair gliders.

Hello, friends! My name is Polina, I have been processing for a year, but I worked only on made machines and with made molds. Now I want to try to make a mold for a compression furnace myself. Could someone share a drawing, please?

Tomorrow morning we will launch our Kickstarter for InFUNity Tiles (https://www.atlas-games.com/infunity). Discovery of this shape was announced earlier this year by David Smith, Joseph Samuel Myers, Craig S. Kaplan, and Chaim Goodman-Strauss (https://arxiv.org/abs/2303.10798). We've been making prototypes with our Precious Plastics machinery, and are running this Kickstarter to fund industrial molds for larger-scale production. (The tooling will cost us about $13,500 total; hence the KS to fund it.) These tile shapes are in the public domain, so anyone in the PP community can make and sell them. I believe @CitSciWorkshop is planning to sell injection molds (they made one for us). You can also make your own, using vector files that are at https://github.com/christianp/aperiodic-monotile, released to the public domain (CC0 license) by Christian Lawson-Perfect We are making the "Hat" tile in two sizes, using the SVG vector files, scaled to height of 90mm (large) or 40mm (Mini). The tile thickness is 1/4 inch for large and 3/16 inch for the mini tiles. I think it would be great if other PP workspaces made these for sale as well! If you want to make custom tiles that fit with the ones we will produce, use those dimensions, and go for it! Whether injection molded or cut from sheets, tiles made with Precious Plastic techniques and tools can offer a diverse range of unique features, colors and patterns. We're happy to offer them for sale all over the world using our own recycled plastic, but it would be even better to see them made and sold locally with local plastic waste, reducing transportation and energy consumption.

2

1

JohnNephew

Tomorrow morning we will launch our Kickstarter for InFUNity Tiles (https://www.atlas-games.com/infunity). Discovery of this shape was announced earlier this year by David Smith, Joseph Samuel Myers, Craig S. Kaplan, and Chaim Goodman-Strauss (https://arxiv.org/abs/2303.10798). We've been making prototypes with our Precious Plastics machinery, and are running this Kickstarter to fund industrial molds for larger-scale production. (The tooling will cost us about $13,500 total; hence the KS to fund it.) These tile shapes are in the public domain, so anyone in the PP community can make and sell them. I believe @CitSciWorkshop is planning to sell injection molds (they made one for us). You can also make your own, using vector files that are at https://github.com/christianp/aperiodic-monotile, released to the public domain (CC0 license) by Christian Lawson-Perfect We are making the "Hat" tile in two sizes, using the SVG vector files, scaled to height of 90mm (large) or 40mm (Mini). The tile thickness is 1/4 inch for large and 3/16 inch for the mini tiles. I think it would be great if other PP workspaces made these for sale as well! If you want to make custom tiles that fit with the ones we will produce, use those dimensions, and go for it! Whether injection molded or cut from sheets, tiles made with Precious Plastic techniques and tools can offer a diverse range of unique features, colors and patterns. We're happy to offer them for sale all over the world using our own recycled plastic, but it would be even better to see them made and sold locally with local plastic waste, reducing transportation and energy consumption.

so cool!

1

Hi Friends - I am based in India and my organisation SparkLiv is upcycling plastic waste and creating over 20 types of products ranging from key chains to 3 seater benches . Our products are made from 100% upcycled plastic waste. While we have launched these products in India, we are equally excited to launch them in other countries too. I would love to know from you all about which specific countries or online platforms to target in order to reach out to right set of sustainability supporting customers for our products.

Friends! Hello everyone. Does anyone have a drawing of a mold for a compression furnace? Could you share, please

Поля

Friends! Hello everyone. Does anyone have a drawing of a mold for a compression furnace? Could you share, please

https://community.preciousplastic.com/how-to/create-a-bowl-using-a-laser-cut-mould

Create a bowl using a laser cut mould

Mathijs will show you how to create an iconic recycled bowl using a lasercut moud.

1

waterppk

There's some things to be aware of ratings-wise for wall covers: https://www.eng-tips.com/viewthread.cfm?qid=244889 some information on the UL website: https://www.ul.com/services/attachment-plug-and-receptacle-safety-evaluations I don't think HDPE/PP that are commonly used here are going to meet the flame safety standard but that wouldn't stop you from selling them

These plastic parts are generally made in polycarbonate for this reason, you can technically do it with Flame retardant pe but you can't do it by yourself you need to do all the certificate and everything

I was with Ivan from Precious Plastic Torino at the Maker Faire in Rome last weekend. I made this mold for the occasion (it's not perfect since the small CNC milling machine I'm using has the tendency to lose motor steps, it has to be fixed by the owner).

5

1

Overmolding experiment to make a carving mallet. Plastic is mixed shop floor sweepings (mostly HDPE and PP). Going to clean it up on the lathe next.

4

JohnNephew

Overmolding experiment to make a carving mallet. Plastic is mixed shop floor sweepings (mostly HDPE and PP). Going to clean it up on the lathe next.

After clean up; still needs sanding and oil on the wooden handle. (The wood is ash reclaimed from pallets.)

1

JohnNephew

Overmolding experiment to make a carving mallet. Plastic is mixed shop floor sweepings (mostly HDPE and PP). Going to clean it up on the lathe next.

I really like that! What are the details on how you compressed the plastic around the handle?

The handle goes into the mould and plastic is injected around it, hence the ribs in the area receiving the overmoulding so it won't just slide the head off when the plastic shrinks a bit.

Exactly. I drilled a 1 1/8" hole in the aluminum plug for the bottom of the pipe. Rough turned the handle so that it was that diameter or smaller, with a top part left oversize to stick up into the pipe cavity. Stuff hot plastic around it, put another aluminum plug on top, use a base in the show press that lets the handle hang down while pressure is applied from above. Second and third efforts turned out better because I was careful about making a nice square shoulder to keep the handle straight with the head.

I'm guessing you need to support the handle from below while pressing? And no part of the handle diameter can be larger than the hole in the aluminum...

1

12:29 AM

What type of press are you using? An H- type freestanding?

No support from below on the handle. The part above the hole is larger so it is held in place. Yes on the press. 12 ton. This is the model: https://www.northerntool.com/products/strongway-12-ton-hydraulic-shop-press-46270

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1:14 AM

More pics. Made a second mallet with shorter head and hackberry handle. Sanded the handles and finished with linseed oil/beeswax blend.

Ah, gotcha! Thanks for the answers, it really helps me visualize.

I should probably do a how-to with pictures...

3

JohnNephew

I should probably do a how-to with pictures...

yes please!

So far my how-to is: Step 1: collect plastic Step 2: ??? Step 3: Profit! Looks like I need to flesh it out a little

1

3

I want to cover them in fluff, and make them in to drumming mallets! (edited)

2:27 AM

I wonder how heavy they are, considering they are plastic?

maize

I wonder how heavy they are, considering they are plastic?

A square foot of HDPE weighs ~60 lbs; compare that to ash at ~47 lbs.

convertin gto kilos haha.. that sounds quite heavy!

maize

I want to cover them in fluff, and make them in to drumming mallets! (edited)

The larger one is 15 oz. including handle/425g. Smaller is lighter. As observed, plastic, even PP, is typically denser/heavier for the same volume of wood.

JohnNephew

The larger one is 15 oz. including handle/425g. Smaller is lighter. As observed, plastic, even PP, is typically denser/heavier for the same volume of wood.

tyvm! yeah it's a great weight! It must feel pretty good!

They both do have a really nice feel, I think. If I make it to the local woodcarving club meeting on Saturday I'll have to see what those folks think and how they might like the design tweaked on future iterations.

mitreapel Silicone Mold Release Spray (14.4 oz) Release Agent Aerosol Spray https://a.co/d/fo9t8OP

mitreapel Silicone Mold Release Spray (14.4 oz) Release Agent Aeros...

mitreapel Silicone Mold Release Spray (14.4 oz) Release Agent Aerosol Spray

Does anyone have a recommendation mold release spray for a sheet press mold ?

New carver's mallet iteration. In this case I took a clintrical blank, bored a mortise into it; turned a tenon on the handle and then added a screw and washer from the top. No overmolding, and it made it easier to have larger contours on the handle without having the maximum diameter set by the hole for overmolding.

9:05 PM

I could turn a plug to fit in the top for decoration perhaps.

Heads awaiting handles. I suppose I should make a mold/form with a built in mortise

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Whats the best Type of Aluminum to make injection moulds from ?

2:56 AM

Looking to do an order from PCBWays for some test moulds

2:56 AM

and there 4 options (6061,7075,5052,2a12) but cant find much info on which ones best suired for injection moulding

JarvisSan

and there 4 options (6061,7075,5052,2a12) but cant find much info on which ones best suired for injection moulding

All of design is a trade. Some might prioritize ease of machining. Others durability. Here is a primmer on different types of moulds, and which alloys of aluminum are employed for each: https://www.howardprecision.com/aluminum-alloys-for-mold-making/ (By the way: that was the very first hit when I Googled "what grade of aluminium is used for injection molding?") (edited)

Agency Jet

Aluminum Alloys for Mold Making

Aluminum alloys are a versatile, and cost-effective mold making material. Howard Precision Metals offers a wide range of aluminum products and extrusions for various industrial, manufacturing, and construction applications.

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I hope this is the right place to ask this here.. Im recycling Pla plastic and was wondering if anyone knows of what kind of silicon skull mold I need to look for that can be used in a toaster oven to pack with pla plastic scrap I looked at so many online and they seem like they wouldnt work or last that long in a toaster oven

silicone bakeware should work in a toaster oven

Any tips on mould cleaner and release agent? What do you use for hdpe sheets?

Hello! could anyone help me with designing a SLA resin mould to trial a product I have designed - i have the CAD design but do not know how to make a mould - it is fairly complex (for me) - will pay for any help / mould designs

JarvisSan

Whats the best Type of Aluminum to make injection moulds from ?

7075 Is the toughest of the three, but it is also a lot more abrasive on metalworking tools. I'm using 6082, very similar to 6061. 6000 alloys are also called anticorodal, 7000 ones are ergal, 5000 ones are peraluman. Peraluman is softer if I can remember well, but I machined too little of it in past years (I'm in the metalworking industry for over 20years) 7075 is the toughest one, it has a tensile strength similar to a good mild steel, anticorodals are something like in the middle. They can also be well machined and polished. If I have to choose, I'll go for 6000s, for molds where you need strenght, a carbon steel is better suited.

1

Davide->PreciousPlasticRomagna

7075 Is the toughest of the three, but it is also a lot more abrasive on metalworking tools. I'm using 6082, very similar to 6061. 6000 alloys are also called anticorodal, 7000 ones are ergal, 5000 ones are peraluman. Peraluman is softer if I can remember well, but I machined too little of it in past years (I'm in the metalworking industry for over 20years) 7075 is the toughest one, it has a tensile strength similar to a good mild steel, anticorodals are something like in the middle. They can also be well machined and polished. If I have to choose, I'll go for 6000s, for molds where you need strenght, a carbon steel is better suited.

Thanks David. Are any surface finishes recommended? like sanding, or chem treatment ?

Hi there, I'm a furniture designer working with digital fabrication by manufacturing furniture in CNC router machines. We usually use plywood sheets to make our furniture, but I've been studying and trying to use recycled plastic sheets instead. The main goal is to make outdoor furniture, where the plywood doesn't perform well. I prototyped this little bench and it has been doing really good under the hot brazilian sun and heavy thunderstorms. Unfortunately, 50% of our clients thinks this material is "ugly" and they are suggesting to paint it. We tried a water based tint, but it doesn't stick well. I'd rather use some non-toxic paint. Maybe some of you would have some tips and resources where I could learn more about painting recycled plastic sheets? Huge thanks!

Hugo Chinaglia

Hi there, I'm a furniture designer working with digital fabrication by manufacturing furniture in CNC router machines. We usually use plywood sheets to make our furniture, but I've been studying and trying to use recycled plastic sheets instead. The main goal is to make outdoor furniture, where the plywood doesn't perform well. I prototyped this little bench and it has been doing really good under the hot brazilian sun and heavy thunderstorms. Unfortunately, 50% of our clients thinks this material is "ugly" and they are suggesting to paint it. We tried a water based tint, but it doesn't stick well. I'd rather use some non-toxic paint. Maybe some of you would have some tips and resources where I could learn more about painting recycled plastic sheets? Huge thanks!

What about tinting with black? Maybe LDPE bags?

Hugo Chinaglia

Hi there, I'm a furniture designer working with digital fabrication by manufacturing furniture in CNC router machines. We usually use plywood sheets to make our furniture, but I've been studying and trying to use recycled plastic sheets instead. The main goal is to make outdoor furniture, where the plywood doesn't perform well. I prototyped this little bench and it has been doing really good under the hot brazilian sun and heavy thunderstorms. Unfortunately, 50% of our clients thinks this material is "ugly" and they are suggesting to paint it. We tried a water based tint, but it doesn't stick well. I'd rather use some non-toxic paint. Maybe some of you would have some tips and resources where I could learn more about painting recycled plastic sheets? Huge thanks!

You might look into flame treatment or corona treatment, assuming you are using polyolefin plastics. But if you are looking to outdoor use, I would think that's pigment in the plastic would be more durable than any paint.

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JarvisSan

Thanks David. Are any surface finishes recommended? like sanding, or chem treatment ?

If milled precisely, no further finishing are needed. If there's some tool signs, you can finish it with abrasive pad like scotch brite, sandpaper, I don't like sandblasting but it is also a viable option, or you can also polish it with a dremel or similar tool with a polishing wheel and an abrasive compound.

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