The previous Green Slime I made looked so good, I wanted to see how hard it would be to make a mold from one so I could reproduce them for sale rather than having to sculpt each one to order.
Sculpting these Slimes, like the one pictured above, is fun and I certainly enjoy it, but it’s not feasible to make and sell them that way. It’s way too time-consuming and therefore way too expensive to the consumer. If I can make molds from a master, I can potentially make many of them in a day, and they can also then be sold blank to be painted any color the customer wants.
I started with some old hand bills to use for card stock to construct a box to hold my silicone and contain it around the master miniature. You can see the reaching Slime master I made in the top left corner of the picture above.
I started out mocking the box up with scotch tape, then hot gluing the seams to make sure it wouldn’t leak silicone all over my desk. I initially cut my 2 inch wide hand bills in half, then added a quarter-inch or so more when I recognized I would need more height to the walls of the box to get enough thickness to the bottom of the mold.
The top edge of the walls of the mold turned out uneven, but I did trim them up in later steps, while I also put a couple of coats of clear coat on all surfaces inside the box. This is to ensure the silicone does not bond to any of the paper or the master, as well as ensuring there is no unanticipated reactions with the silicone in contact with the other materials. Silicone will not perform well if it is contaminated, particularly with any latex or latex based adhesives. I wear vinyl gloves, not latex, for this reason.
Initially, I was going to suspend the master in the silicone. Thankfully, I realized what a mistake that was going to be. Instead, I hot glued the master into the bottom of the mold box. The reason is there is a hollow center area in the master between the tentacles of slime that reach out. If I filled the cavity from the bottom, there was going to be a bubble inside the center of the master that would not get filled. I’m glad I anticipated this.
I stirred and poured my parts of silicone, then sprayed a final coat of clear coat on the master and the mold box to make sure I was avoiding reactions and bonding issues. While I worked I covered my unmixed silicone parts to ensure debris would not contaminate them.
The product I’m using here is OOMOO 30 2 part silicone rubber compound. It is brilliant stuff! You mix equal parts so you don’t have to measure if you have clear plastic cups. It has a pot life of 30 minutes and a cure time of 6 hours. The resin I will be casting with is also a Smooth-On product, Smooth-Cast 300 2 part resin. It is also equal parts, so no measuring, but it only has a 3 minute pot life and a 10 minute cure time so I’m going to have to work quickly!
Demolding the master proved to be simple, it slid out perfectly without any sticking.
I’ll definitely be considering making a mold of my first Slime sculpt, the one in the first picture on this post, and maybe others. A variety pack of dungeon Slimes is a sure possibility!