How to Cast Resin Figures

Polyester resin, a popular material used in both molding and casting, is often used to create dolls and other figures. Unlike laminating resin, casting resin dries with a smooth, hard surface perfect for detailed work. The basic process of making resin figures is fairly simple, though the materials used to make them are considered highly toxic and dangerous, and take some skill and practice to successfully master. The resin casting process involves creating a two-part silicone mold of an object into which hot resin is poured and set to harden.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Sculpey clay Oven Latex gloves Goggles Protected workspace with forced ventilation Vapor respirator Stirring tools Silicone RTV rubber and catalyst Rubber bands Razor blade Polyester casting resin and catalyst Wooden molding box Small wooden craft balls or marbles Acrylic paints and brushes Polyvinyl alcohol

The Mold

1. Choose an existing figurine that you would like to copy, or sculpt your own using Sculpey clay. When finished, bake the Sculpey as directed on the package to harden it and let it cool before proceeding.

2. Make an open-top wooden box the size of your figure, or use an existing box. Be sure that you can easily disassemble the box and that the figure, when lying down, will have a clearance of at least 1/4 inch on all sides, and that the box is deep enough to pour a mold.

3. Mix up a small amount of silicone RTV rubber, following the instructions on your particular product. Be sure that you are mixing the proper amount of silicone and catalyst. Pour enough silicone into the empty box to reach the halfway point.

4. Press the figure into the silicone so that it is half-covered, but leave enough space at the bottom so that the figure does not come out the other side. Beside the figure, set some small wooden balls to create keying depressions. Let the silicone cure for 12 hours.

5. Remove the wooden balls from the cured silicone. Mix up another batch of silicone and pour it over the rest of the figure, filling the box. Let the silicone cure for 12 hours.

6. Disassemble the box carefully and separate the mold halves. Remove the figure from the mold.

The Cast

7. Match the two halves of the mold together and strap them closed with rubber bands. Stand the mold bottom-up and, using a razor blade, carve a hole into the center.

8. Mix the casting resin, following your product's particular directions. Make sure that the resin and catalyst are well-stirred.

9. Pour the resin slowly into the hole in the bottom of the mold until the mold is filled. Pour slowly, so that you do not develop air bubbles in your resin. Let the resin cure for five hours.

10. Unstrap the mold and take it apart. Remove your new resin figure from the center.

11. Sand the resin smooth, if desired. This must be done underwater, as resin dust is highly toxic and should never be inhaled. When finished, paint the figure with acrylic paints.

Tips & Warnings

• Sculpey can be sanded before casting for a smoother finish. You can also use plaster as a molding material. Clean up spilled resin with polyvinyl alcohol.
• Forced ventilation and a vapor respirator are absolutely necessary for safety when working with resin. The fumes are toxic. Never let resin touch your skin or eyes. Resin can cause many skin problems and permanent eye damage. Always wear latex gloves and safety goggles. If you get resin on your skin, immediately clean it off with polyvinyl alcohol and then soap and water. Never smoke when working with resin.

Resources

• The Prop Builder's Molding and Casting Handbook
• How to Make Molds
• How to Make a Two-Part Mold

[viperonethree]

on 3/26/2009 Pictures would be nice in the future, but nice write up. One question though, for Step 4, when one presses the figure in, do you suspend it somehow? How does it not sink in? Is the silicone from step 3 half "set up" at this point? How long would it need to cure/is silicone naturally thick even before it sets?