Mould Design Community, what if…

Hi everyone! I’m absolutely excited with the idea, it’s a great one and with a big set of tools to go on but I just find a “weak point” about all this stuff when we pretend to recycle and reuse the plastic on Dave’s machines… MOULDS!

There is nothing to do with an extruder machine without a mould… so I’m wondering how can it be fixed and it is not a simple matter.

The first “pain point” is about mould design. It is not only a matter of shape but also a question of architecture as the final product should be “nice and useful (durable)” so I want to invite everyone on a discussion about “design inteligence”. My point of view is that the “designers knowledge” should be implemented on the project and maybe to create a “Plastic’s Design Market” where any producer could buy or borrow a plastic mould design to made.

On the other hand, once there’s a mould to be made, we should talk about aluminium recycling for greensand casting or CNC milling; so there’s a need about aluminium casting techics, technical knowledge and technical skills to provide… but also CNC machines building, stepper motors control and CNC software for mould designs making.

I think that it could be great if we find the way to merge design knowledge, mould design libraries and a mould makers list to give this project a “ready to go” state.

About mould casting, I would like to advice about how useful and efficient could be a “mould makers network”, as it is needed various requirements to produce quality moulds for long lasting use and production such as machinery, knowledge, space, and so on… maybe to arrange a regional clustering could be a must in order to maximize start-up speed and reduce production expenses to someone’s project.

Do you want to join the discussion?

Thank’s for your attention 🙂

Edit, Moved to PreciousPlastic forum


I have had the same discussion for years!!! But I think more and more people are making molds, so I hope the prices get down, so the complexity.  In Mexico we are looking for alternatives, for example we use the inyection machine to melt the plastic and the use a press

Saludos desde México

This is a great thread! I am currently experimenting with mouldmaking options involving lost wax casting of aluminium, cast plaster, or hand machined aluminium.
My addition to the thread, in relation to posts higher up about CAD design of moulds, is that I’ve found STEP files to be the most commonly used especially for 3D printing. I’m a Sketchup user, but the free version doesn’t allow export of STEP files only COLLADA files; but I’ve found that online convertors work fine to translate a COLLADA file into a STEP file you can download. I have sent these to for printing and they work fine, you just have to be careful that your units are correctly set to inches or mm so that your print comes out to scale.


Hi there,
We did some coke can plastic melting test. The results described in our topic here.
If you just scroll to _Weekly update number 11 _you’ll see the result for just taking a can and filling it with PP and placing in an oven. This could definitely be machined to meet the product design specs (and also cheap and easy to make)

I made a simple mould of wood and steel.
Used PP and HDPE to test it and it went fine. I coated the wood with heat resistant spray on te first use, but the spray came of.

I wanna play! My aim is to take coke cans and make mold sets, depending on the mold needs various pre-made bricks will be machined to desired specs.

Hello It’s been long time since I haven’t follow up on this.

So the main reason it’s that is has been a fail for  multiple reasons, I ll try to explain my tests so you can learn from it.

The silicon molding went perfect I clean it up after it dried with a blade.

So i my first  2 or 3  attempts to pull plastic into it every I failed because the mold was to cold so every time I would push some plastic into the mold the plastic would get lower in temperature and get harder so it would not fill the mold.

At the end i decided to put the mold into the hoven but the mold wasn’t supporting the high temperature and bubble would create in the mold deforming the mold.

So to conclude story is to be continued….

I’ll try again with silicon with a higher temperature resistance to melt the plastic directly into the mold will se how it goes

I’ve been investigating this process specifically.

Hi. I’ve read through the forum as the subject interests me. I’m a professor at a design school. I focus on process and production and i teach techniques of woodworking, digital fabrication, moldmaking, and plastics. In one of my classes we work with Precious Plastics. Currently we’re investigating the what do you make with the machines and how do you make it. You’ve gotta make something to make something. I think that version 3 of has begun to address this question.

There are various techniques and materials from cutting edge technology to traditional approaches that can be achieved and implemented. The questions are what is appropriate to the situation. There will never be a one size fits all solution. There is the question of what is available and what can be afforded. There are the basics of what will and won’t work are wether a material is an insulator or not, how well does it disperse heat and can it be cooled. Similarly to how plaster works for ceramic molds because it permits the evaporation of water allowing the clay to dry out and harden. The mold material needs to be appropriate to the required results.

Aluminum is an industry standard. It’s versatile. It can be cast, formed, machined, etc. Wood is used traditionally in glassblowing. It works but not as precision as aluminum. I’m investigating many different directions with my class and personally looking at the use of SLA printers to make “inserts” that can go into aluminum “mother molds” for use. This white paper from Formlabs describes the process. I’m looking at it as an alternative to machined aluminum.

Curious to see the result…
I work also with silicon mold.
But never didn’t them myself


@dbougas got a little delay but I actually got the materials to do it yesterday . I will try this week. Keep you posted 😉

Any news on you try?

@jegor-m I think its used for a way to quickly protype an idea. It’s used more in a workflow than to produce things.

@plastikfantastik, a vacuum former is indeed easy to make, but why would anyone make one?
What type of useful product could it make?

I’m just trying to come up with some cool ideas and have had no luck yet.

the vacuum former is an easy thing to make !!! go diy!!! you can make from recycled materials
check this out @dzspain


I’ve not heard of cone-trainers before, but a quick google gives this approx an inch diameter by 4-6″ tall?

Apart from the making of the mould, which looks like it would not be too hard for a competent machinist, there’s the question as to whether the injection machine could actually produce this, thin walls require a lot of pressure and quick injection of the plastic (see the problems Jerry had with the phone cover for a good example of what’s possible). Also as these cone trainers cost less than $0.10 each and it would take a reasonable time to mould each one, with possibly some cleanup/finishing also required, I’d have to ask if it’s really worth the effort involved to produce them yourself (other than the obvious environmental benefits).

I think this is a fantastic idea. Mold/Mould making is the bottleneck in this whole process. You have the machines, now what? I’d love to be able to produce small pots for planting tree seedlings (similar to Cone-Tainers), but to make a lot, relatively efficiently, I need an aluminum mold, and they seem to be incredibly expensive. It seems like it might be possible to create one by hand, but creating an accurate aluminum mold by hand would probably be extremely difficult. Instead finding people with milling machines who would be willing to collaborate would be amazing!


Would love to see this, please post the results and video – even if it’s not a success, maybe others can learn from any mistakes.

Ok this topic got me exited… I don’t have a shredder, i don’t have any of the machines but I have my kitchen hoven (wich will do the job).

So next week i’m gonna try to remake a iPhone case in HDPE based on a cheap silicon mold. I ll make a video to document my experience.

If anyone as some advice feel free to share it (I already look up on youtube).

Keep you updated. 😉

I’d like to get help with a clipboard, rule, and pencil case to help kids with school supplies. Household items would be cool too.