Fun With Mold Making

This just goes to show that when you ask a question at a retail store you can most definitely expect to get the right answer every time because customer service is job one. And to that end I was very surprised to see at the local Michaels that they not only carry several different brands of mold making materials but they also carry several kinds of resin to make parts out of too. So, even though I had asked the store clerks while visiting this location a couple of weeks ago and was clearly told that they did not have anything like this, here were the exact products I had been looking for. My only conclusion is that these must have been stocked immediately after I left the store the last time and the poor clerks were none the wiser.

I looked at four kinds of silicone mold making kits and eventually went with Sculpey Moldmaker which states on the box that the mold is soft and pliable to shape around the most intricate details. Then when the material is cooked in a conventional oven it makes an Elasticlay mold that is permanent and flexible. This was around $10 for two 4 oz bars of the clay-like material.

The instructions say to use a small amount of the mold maker to make a copy of the part you want to duplicate. You are supposed to cover the part in corn starch so it can be released from the mold maker easily then you just bake the mold in the oven at 275 for 20 minutes. It turns out that all of this is easier said than done. The pliability and softness of the mold maker also goes along with making for a very sticky and very easily deformed consistency. It’s all well and good getting the part down in this stuff but the real trick is removing it again afterwards without warping the whole mold while extracting the original part. I think that what the instructions should tell you to do it what I eventually figured out on my own.

1. Get a small aluminum pan that can be placed in the oven

2. Cut off a section of the mold maker and then use corn starch on your fingers so you can work the material without it sticking to you

3. Once you have shaped the mold material into a small disc place it into the pan

4. Keep as much of the corn starch out of the pan as possible and that way the disc of mold maker will stay in place when you remove the original part

5. Put corn starch on the original part and press evenly into the mold blank. The original will be a lot easier to press in and then remove if it has something sticking off its back or if you attach a temporary handle maybe using a hot glue gun. (I ended up gluing one gear down onto a piece of cardboard to make one mold by pressing the material over it. This would have been simpler if I had just glued the gear to wax paper, but you know hindsight and all that.)

6. If you have succeeded in removing the part and have not changed the shape of the mold in the process you can then place the pan in the oven and cook it for 20 minutes.

I ended up making six different molds tonight and interestingly enough they all turned out to have the feel of erasers once they had been cooked.  This is supposed to give them the ability to hold their shape when you pour liquid resin into the impressions and then enough flexibility to stretch to allow the hardened resin to be released.  The next step now is going to be to get one of the resin mixes and pour some into the molds to see how good these took.  Hopefully soon I will be able to start making my own resin gears for steampunk modifications and I will not have to worry about running out of any particular style of gears.  Wish me luck.