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Mould Design Community, what if…???


This topic contains 121 replies, has 38 voices, and was last updated by  Dan Shirley 3 months ago.

Dario Zanon dzspain

Mould Design Community, what if…???

10/05/2016 at 12:16

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

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24/09/2016 at 11:03

That would be a job for @andresornelas, he’s the one currently experimenting with plaster

24/09/2016 at 10:59


Looks like a nice idea! Plaster is a great and pretty cheap solution.

Can you maybe make a tutorial for the wiki?

Keep up the good work!

24/09/2016 at 06:25

@trishkabob I came here just to talk about that exact same thing 😉

@dzspain @birdynamnam @uaneme @paulenglish @redgurrillia @timslab @n-w-b @richoz27 @davehakkens @robksawyer @paulaortega @winbidtm @andyn @bianca

The guys from Precious Plastic México are currently testing molds made with plaster, and seems to work perfectly. The advantage of using plaster for moulding is that plaster is super cheap, non-toxic and the moulds can be easily replaced if one breaks.

Look at their project here:

Here’s the official post about their project on the forum:


Injection Molding Tests

04/09/2016 at 01:50

Has anyone tried plaster casts for molding? Dental die stone is quite hard, I wonder if it would hold up under the pressure to be used over and over again.

25/08/2016 at 19:29

@uaneme It’s a privilege to meet people like you. You brave, kind hearted man 🙂

@birdynamnam, it’s nice to see you here! Same as all the folks here!

I’m on vacation, enjoying my family and friends on the hot sunshine days of western Mediterranean sea. Coming back to rutine in… six… five… four…

30/07/2016 at 12:14

Hey @dzspain @uaneme and all,

Big apologies for the radio silence. Looks like you all have been making fantastic progress though – the furnace looks great!

So, like all us, I’ve been really busy with work and the injection moulder has been languishing in a corner of the workshop looking rather sad with its electrics box opened up. My wiring has let me down and I need to reassess what has gone wrong as now a band heater isn’t working!

Hoping to do some work over the next few weeks as @paulaortega is excited to try her moulds!

Back soon!


10/07/2016 at 22:33

@dzspain Hehe the cat already approved the furnace.

Thanks for the kind words, though i’d like to forward them to all the people who develop Free Software for making this possible, i only show that it is available, and actually works. (almost as good as insanely overpriced software)

Good to see that there are now also online CAD editors, but after reading one of daves last posts (he mentioned very bad internet connectivity) i’m sure that this is no option for countries where the infrastructure is more fragaile then what we are used to. And with the current financial crisis we can see that our internet standard is also coming under thread, not to speak about Netflix’s attempts to undermine our net neutrality. Then only the rich people can enjoy fast-lane connectivity. And that would eventually render online CAD useless even for us. So for those who want to use that, enjoy it while it lasts, but keep in mind that there is Free Software that still can do the trick.

Now you can also start collecting soda cans. 🙂

How much aluminium can you melt in one go with this?

09/07/2016 at 13:04

Full closed

07/07/2016 at 05:42

@uaneme you said you want simple cad for everyone, then you talked hardware and operating systems. Are computers that are not attached to the Internet widely adopted in third world countries? If so, without the Internet how would these people even learn about the previous plastic project in the first place?

For CAD to be truly accessible for all does Web based make the most sense? Even a homeless person in my country could go into a public library and access the Internet to use tinkercad. With no experience I’ve found tinkercad to be easy to learn and create with. I believe it’s worth a try for anyone anywhere, check it out: http://www.tinkercad.com

03/07/2016 at 22:03

Welcome @winbidtm, many thanks for your help offering on CAD @richoz27 and yes, you’re right about quality producing to make the project as useful as interesting to everyone, thanks @bianca for your input and congratulations for your jewels they look nice! @richoz27 posted a video upwards about injection and @paulaortega and @birdynamnam are experiencing with heat resistant silicone moulding, @andyn gaves a brilliant idea to simplify the process on dayli ovens, thank you so much for your inputs and suggestions @andyn.

Thanks @uaneme for your view and concern about the best practices for CAD modeling and @richoz27 inputs too. Great job @robksawyer!

I’m still quite busy with my training course but I finally made a little furnace for aluminium casting, not finished yet, I should remove the inside mold and make the melting pot.

@uaneme, about to split the topic, I think that it could be nice as this one was wiling to be focused on mold designers community instead of molds making and trouble fixing but… you can see, human spontaneity has its own way and I’m grateful for all the great ideas added here. Maybe we should ask to the rest of users what they think and how they would like to organice the discussion topic 🙂

29/06/2016 at 22:22

Thanks @davehakkens!

29/06/2016 at 00:47


This thread is growing a bit long. This forum does not seem to make new pages so people need to scroll a lot to get to the bottom.
What if we make a new topic. Same name (part 2) just to make it more usable.

26/06/2016 at 11:57

wow @robksawyer amazing job on the wiki! Looks very clear, thorough and organised. Keep up the good work 👌

22/06/2016 at 06:17

@robksawyer thingyverse is in a way a nice platform to promotethe project, but their terms are not just bad, they are evil.

I think Youmagine has more respect for the creator, and human readable terms and conditions. (the only one on the list so far that can be understood with needing a degree in lawschool…)

Do you have a picture of the LEGO + silicon mould? (if yes, please add it to the wiki!!)

21/06/2016 at 09:42

@uaneme The brick I did needs work, it would need to be mostly hollow I think to keep wall thickness consistent and reduce the amount of plastic used.

First thing is to get the function right, then make the mould easy to make (design for manufacture). There is a lot of plastic around and its basically free.

Your STEP file works fine for me, its a format that most CAD programs can use.

Using CAD, you just need to sit down and play with it to learn, thats how I started.

Lets talk about it here instead of derailing this post any further 🙂

Interlocking Brick Design

21/06/2016 at 08:20

@uaneme I’m guessing you added those details? 🙂 If so, thanks! I added the Precious Plastics machines to Thingiverse before I was aware of their terms. I need to look into this more.

Related to the lego bricks, I’ve made small silicone molds using this technique. It works great. Just build four walls of bricks and use Plastilina (non sulphur) clay to fill cracks on the inside.

21/06/2016 at 06:58

@robksawyer https://preciousplasticwiki.herokuapp.com/index.php?title=Mold_Design
Please check.

@richoz27 I’m not a CAD designer, but I have used FreeCAD a couple of times.
It has a bit of a learning curve, but to me it feels very intuitive. I manage to do the basics and a bit more. Alltough often I tend to do simple things in a complicated way simply because I don’t have any background at this.

I’m just amazed how much is packed in that application, and how lightweight it is on the CPU even on a 7 year old netbook it works without any issues. (basic use)
And it runs on Apple, Windows and Linux all just the same.

I tried to download the STEP file but GrabCAD forces me to sign up..

I do like the interlocking brick i wonder if t could be used as mould case outer wall? (with a clay or silicone mould inside) This way we can fabricate parts to use in part fabrication. When broken we can recycle, improve and break it again. without making more mess. 😀

And yes, making houses would be cool. Even dog houses, chicken barn. (for Frieda’s family?

Allthough it would me more economical to make some kind of coupling system, and then use more classic materials (wood panels?) A 100% plastic wall is A LOT of plastic. But yeah it would at least clean up a chunk of planet.

What about lego style brick roomdeviders?

The nop things at the bottom appear to be a bit odd.

I slapped together a rough block in FreeCAD and uploaded the Freecad file and the object exported as STEP file.

What do you think? Is STEP usable? or could there be better options?

21/06/2016 at 06:13


Solidworks can export/import STEP files, have you used FreeCAD? I will look at it soon, I have updated the Grabcad link above to include a step file.

21/06/2016 at 05:57

tinker friendly as in, friendly to people who like to tinker.
Low/No budget.
Minimal hardware.

Since there are people from all over the planet with different budgets, and with a wide range of hardware. I guess the range is somewhere between Windows XP and Apple (and a few people like me with Linux)

I’m trying to figure out a solution that works for everyone (literally everyone) if possible. I know this will be hard, but i’m trying to push this to the forefront since I’m sure we can do this. (If we want)

Not saying you should give up Solidworks, but more something in like. Please think along when you export a file and export it in a format that more programs are able to load then just your program. I don’t know what Solidworks can do there (this is where you probably can make some suggestion?)

All i know at this point is that .STEP exported with FreeCAD works fine with AutoCAD and another pro-CAD program that I don’t remember from the top of my head (Not Solidworks)

Maybe we can put the findings in the Wiki? (@robksawyer ?)
How to display compatibility between software?

@siteadmin It also might be cool if every user profile had the option to add information on what software packages people are using. What machines they have etc.

21/06/2016 at 03:53

@uaneme I use Solidworks, not sure what you mean by tinker friendly? But it can output many types of CAD formats.

I saw a really good idea the other day, interlocking bricks for building houses etc… from recycled plastic (like a big Lego block). I have already started the design but I would like to share it and get other peoples feedback. I think if we can come up with a simple design that can turn waste plastic into building blocks this would be really good for developing countries.

Download it here, this is soldworks file though. This is just a rough start, in need of more development.


It should be:
– Simple interlocking design
– The mould needs to be easily constructed and reusable over many times
– Injection mould friendly (consistent wall thickness etc)

Turning rubbish into houses would be a great application for this.

Give me your feedback and ideas please 🙂

21/06/2016 at 03:26

@winbidtm Regarding the search/and forum I think @Hansie is planning to give us a better forum.
The Wiki: Maybe @Hansie can place the a link to that wiki on the preciousplastic site? (I hope that request is being noticed by someone who can actually edit the website)

@bianca / @paulaortega I think it ultimately will be a 3 or more part mould. As mentioned somewhere before

1 ‘standard part’ to hold the nozzle, a left and a right side part (or top and bottom)

Making re-usable moulds is really essential. recycling is key, we should make less mess then the mess that is being cleaned up. 🙂 Big industry should already be that wise, but apparently they are just ignoring the mess they made.

From the looks of it your moulds can be stackable, and then there should be some kind of container to around them (wood?) to keep them in place and to add the nozzle

@richoz27 What CAD application do you work with? Any idea’s if it can output a tinker friendly file type for people that can’t afford expensive CADware.

And how do we share/exchange our files? (is there a simple solution that everyone can use? And that also respect us as human beings. (unlike thingyverse!! They are known to steal ideas, and they even made their EULA in such way that you have to agree with them that they may rob you)
I hear Youmagine is a bit more humane? Any other options?

20/06/2016 at 13:15


Hi Paula, could you make this as a two part mother mould to go around the silicone and be clamped together?

I imagine the silicone would be reusable even if you have to cut it a bit to peel it off the moulded part?

20/06/2016 at 13:08


Silicone will be able to take the heat, but being rubber it will probably deform under the pressure needed to compress the molten plastic into it. You could probably minimise this as you say by backing the mould with something more rigid. A thin silicone mould in a metal ‘tray’ (maybe made to fit) might work better than plaster or wood, as metal will conduct the heat to the mould better.

If you use HDPE/LDPE (2/4) these produce no fumes or nasty smells at the temperature required to melt them (200°C or so). They will make smoke/ fumes if you actually burn them but even that is safer than some other plastics. Avoid PVC, ABS or anything you’re not sure of, these can release toxic fumes. Polypropylene (PP/5) is also fairly safe. Ventilation always a good idea though!

Making a compressed flat sheet and cutting designs out of it might work well and you could get some interesting patterns if you mix the colours you melt. HDPE does not cut well on a laser though, it tends to melt/burn the edges, if it’s very thin and the laser has air-assist it might work acceptably. (Definitely don’t cut PVC on a laser, nasty fumes!)

If you can export your Adobe Illustrator files as .eps or .dxf these can easily be converted to g-code for a CNC machine. This would need to be done by the machine owner though as you also need to know some details about the machine and the cutting tools.

20/06/2016 at 09:25

@andyn Thank-you, I just looked at the hackerspace website and found a great place to join that I didn’t know existed – They have many things I need to make the shredder but unfortunately no CNC machine.

Yes, I make the patterns for the mould using Adobe Illustrator. So hopefully these files can be easily converted. It really depends on the cost – I haven’t quoted many places yet for the plasma/water/laser cutting of the shredder parts or for the moulds.

I was wondering why you think the silicone moulds won’t work? Sorry I don’t know much about casting plastic. I use the pinkysil 2 part silicone and it mentions that it is not food safe, but there are a lot of silicone baking / cooking trays so maybe the silicone mould might work. I might see if it would help to set the silicone moulds in a plaster to add some strength around them?

I will experiment and see if I can get this to work, if not I will try making a sheet of plastic on a metal baking tray and then see if I can laser cut the shapes from the sheet.

You are right, I will definitely just shear the plastic with scissors myself, instead of building the shredder while I’m working on proof of concept experiments.

I am a little concerned about the fumes when melting the plastic, despite having a well-ventilated studio. Another reason I am switching from resin is because of allergic reactions I am having! So I am hoping this recycle plastic-smithing won’t be another thing that could affect my health!

19/06/2016 at 19:37


Unfortunately, we haven’t had time to test the mould this week so cannot report back yet. Hopefully next week! However, what’s bothering me is that this mould, even if it works, would be a 1-off mould. Perfect for my one-off sculptures but not so good for making several parts/day.


19/06/2016 at 12:57


Thank-you Andy for getting me on the right track! These ideas are a great start and I will do some tests once I make the shredder. I will be able to find someone to make CNC’d aluminium moulds – I am not sure how expensive mould making is in Australia. I will post photos of the new designs in the coming months!

19/06/2016 at 11:28


I should think you can do this with a version of the compression machine, perhaps in a regular oven using weights instead of having to drill holes in the oven shell for a jack/press.

You might have to do some cleanup to remove excess around the edges of the mould. And you might need to use something stiffer than silicone, as your designs are flat, a CNC’d aluminium mould would be quite easy to make if you can find somebody local to do it.

18/06/2016 at 23:49

I second that about the wiki, finding things here is not the easiest. Is there a search for the forums? Say I want to find posts about “PID controller”.

18/06/2016 at 17:36

@n-w-b, nice to read you! 🙂

18/06/2016 at 14:31

Hi people,

Im still alive and well. Been busy with school. I like the idea of thr wiki. Indeed finding info on a forum is challenging. When im homr again I will take a look at it and contribute where posible.


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