Silicone Caulk Glove Mold

A Silicone Caulk Glove Mold by Joe Hildreth

E X P E R I M E N T

In this example we are going to use a clear silicone caulking to make a simple glove mold. The master in this example is a Pawn from a chess game that I bought at a yard sale. The people next to me thought I was crazy for buying a chess set that had some missing pieces, but little do they know that armed with a little molding knowledge I could replace them.

Step 1

This is one of the pawns from the chess set I found. I want to reproduce this piece.

Step 2

I will need some sort of base material to attach the master (pawn) to in order to create a glove mold of it. There are two items here. The one on the left is a 4 inch ceramic tile. The nice thing about ceramic tiles are they are slick and heat resistant, which gives them other uses besides a base for your master. The other is a piece of Plexiglas

Step 3

Here you see that I have attached the pawn to a base. I used Tacky Glue to glue the pawn down.

Step 4

Silicone rubber comes in a variety of packaging from small tubes like the one pictured to the left, to Large tubes that you load into a caulk gun. The tube to the left is DAP brand 100% Silicone Rubber Sealant manufactured by Dow Corning.

Step 5

Silicone caulk by itself is much too thick to readily coat the master without trapping air and ruining the mold at the surface of the model. The purpose of this whole experiment is to see if the Silicone caulk can be thinned down to a consistency that can be painted with a brush. I have read on the Internet that it can be done with Naphtha. Naphtha is a petroleum distillate that is used for a variety of products, but the most easily found is lighter fluid, the type used to fill Zippo lighters.

Step 6

I put a big glob of silicone caulk into a little container and mixed in Lighter fluid until I had the consistency of honey. I am keeping it in this little sealed container hoping that it will keep between coats.

Step 7

With the silicone mixed up, I started painting the pawn with its first coat, paying attention to get all of it coated with no trapped air. Additionally I painted the entire base of ceramic tile. I will give this three coats giving each coat enough time to cure completely.

Step 8

Two coats of thinned silicone have been applied and two coats of regular silicone caulk have been applied to the model, giving ample dry time between each coat. Now to pull the silicone from the master. (Ooops - it seems that I forgot all about mold release. I kept thinking that silicone would not stick to anything slick or painted. I should have fun getting this off!)

Step 9

The glove mold removed from the master! Well it went better than I thought. I had to help release the silicone from the ceramic tile with a model knife but the silicone pulled from the master without a hitch! Success? Maybe, we have to cast this bad boy yet!

Step 10

Here I have the mold turned upside down sitting inside a can cooler for support and ready to fill with plaster.

Step 11

Here I mixed a batch of plaster. Mixing plaster is an art form in itself. I normally put some amount of water in a cup and start adding plaster until I have little islands of plaster sitting on top of the water. When I reach that point I mix the plaster up and let it sit for a minute or so.

Step 12

Here I have filled the new mold with plaster. I "treated" the mold with a good spray of wet water. (Wet water is water with some liquid soap added to it. It is used to break the surface tension of the plaster and allow it to flow into the detail. After about 8 - 10 minutes the plaster will have set to the consistency of toothpaste. At this point I take a flat scraper and scrape the plaster level with the bottom of the mold.

Step 13

The finished pawn turned out pretty nice. No air bubbles or real imperfections. I should say I will be playing chess in no time now with this set. :-)

NOTES:

1. My first attempt will be to put 100% Pure silicone rubber sealant in a small jar and mix Naphtha into it until it has the consistency of Honey or molasses. (Result: The silicone thinned with the Naphtha just fine)
2. Once it reaches this consistency, I plan to paint it on the model much like Latex Mold builder pictured below. (Result: The silicone was easy to brush on the model and still cured. A success!)
3. As another test, I want to see if it will "keep" in the jar and remain usable between applications. (Result: After I waited for the first coat of silicone to dry, I opened the jar to find that the thinned silicone had thickened up and was a bit clumpy. Note: Only thin enough silicone to do a layer.)
4. I will use an acid brush to apply the silicone, as I expect the brush to be ruined between coats. (Note: You can wash silicone out with Naphtha. At least enough to continue using the brush on the project.)