Making Molds for Polymer Clay

So, I like to play around and make things with Polymer Clay. I have my RoBo and keep imagining creating shapes, characters in solid-works and then make two sided ABS molds to squish super sculpy ball into, making the positive of the shapes. I am sure I would have to acetone fume the parts so they would be smooth inside.

Now I can't imagine how to get the positive out of the mold. If this could work it would be excellent! I thought maybe freeze the mold and pull it apart to get my positive.

Have any of you tried this? Any ideas?

 

I have been tinkering with molds myself and could actually use some help on making the digital molds in the first place. But in my research I've found that a lot of molds have ejectors that push the positive out. They are basically cylinders that when pulled back make up part of the mold surface and when pushed forward, into the mold, eject the part. If you look at many molded plastic parts you will see the little circle on the back side where the ejector was located in the mold.

 

Yes, I wok in an Injection Molding facility and yes you are right about Ejector Pins. However I only think they would stab the clay. I might just have to experiment. Maybe coating the object with powder would work. Could be epic if it works. I am not finding anyone doing this on the web with Polymer Clay. The only clay things I find are Clay 3D Printers. No fun there.

 

Gotcha. Well, according to Wikipedia, you can cure (bake) polymer clay between 265-275F to harden it. That's only about 130C, which your mold should be able to withstand no problem. Maybe I'm further explaining things you already know, but I wonder if you could just cure the clay in the molds and then eject or even just pop them out?

 

I would think if you baked it inside the mold, the creature should come right out. However I have been concerned about the ABS deflection temperature (temp at which it might deform). https://www.plasticsintl.com/datasheets/ABS_FR.pdf This site indicates around 214°F at a slight pressure. So I believe the mold would be warped by baking the Polymer Clay in the mold.

My other thought was to cool the Mold and the polymer clay to a point it is hardly workable and then remove the creature. However, it might fit too tightly to accomplish this. Vent holes might be needed.

 

Have you considered other plastics to print the mold in? I just got some polycarbonate filament which prints between 265-300C and is wicked strong. Nylon might be an option too but I haven't used it myself.

Or you could print the positive of your figure to make a real mold for it out of resin or fiberglass or something that won't deform at temperature.

 

Oh man Mark... that is an excellent idea! Not sure how it would hold the shape from both sides of the mold but then the nylon could be an insert into a stiffer shaped mold.

 

Makes me wonder if my Ninjaflex would work for that as well.

 

Thanks, I will try Nylon then. Thanks for the idea. Ahh well about Ninjaflex, I got it for wheels and stuff anyways. Simiflex is interesting as well but I bet nylon does the trick.