This weekend I set out on the challenge to make a mold of a character that I 3D printed.  the 3D print is an entirely different discussion, but where it lead me is that it would be too costly to create duplicates for sale.  So I thought, why not cast it.  I did some research, which lead me to a company Smooth-On that had a location here in Charlotte.  The offices are Reynolds Advanced Materials and they have mold/casting supplies and also things for special effects etc.  I had gone there a few times so I thought I would give it a shot over the weekend.  I got a mold kit and liquid plastic from them along with some advice.



This character had 4 movable parts, so I had to make 4 molds.



People tend to use cups to create the mold, but the head and body were too big for that, so I saw that one other way was to make a box out of foam core.   I gave it enough room around the sides (at least 1/2 inch) and fond a flat place to glue it down with hot glue.  The flat area is where you pour in the liquid plastic when the time is ready.


I used cups for the arms and had everything in place.  I had used the clear rubber for the mold, and it was time for me to put it together.  You take equal parts of each chemical and mix them.  For this mixture you have 6 minutes to work with it before it becomes too solid, so I didn’t have much time.  It is important to thoroughly mix it but also try not to get bubbles in it.  I poured into the lowest spot and let it fill in.

The arms were a challenge.  I put a dowel to prop it up so there would be enough mold to surround it.


20150524_123032 This is the mold, waiting to fully cure.  I had to next remove the foam core and cup.  That wasn’t difficult.   The hard part was removing the model from the mold.  I think there were some things I can get to help remove it.  I learned not to be too gentle prying it loose.  The head and body were easy, and the arms were difficult.




Here are the molds.  I used a rubber band to hold it together a bit.  not sure if that was needed, but why not.  Next it was time to add the plastic.  There are many options of plastic based on material and how long it takes to harden. I also had a green color tint, just a drop.   I poured it in and waited.  I purchased the medium timed one, but I guess they gave me the quick one instead.  I think I’ll try the medium next time.

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The Head had some holes from the bubbles and I had to drill a hole where there was one from the original design.  The body had some holes by the toes and the feet were a little over run.  The holes in the arms were filled in a bit.  The arms were the trouble.  I knew it would be since I had trouble getting the original out of the mold.  The plastic didn’t fill in the mold entirely.  I even poured it a second time using a syringe, but it still didn’t fill in.



Conclusion:  I feel like I’m almost there.  I was a bit disappointed that it didn’t turn out, but the head and body were close.  I have another new kit, so I may make a new mold, but before I do, I want to figure out the arm problem.  I’m wondering if I make the arm peg thicker, and use that as the hole that I fill in the plastic, that may work.  I would have to make the arm hole larger too, but I could use a drill.