I'm going to review two types of molds using the same materials and principles. The first will be a simple block mold. The other will be the same block mold but it will include multiple castings. This is often called a gang mold.
You're going to need:
- RTV silicone. I will be using Smooth-On OMOO two part silicone molding compound. This is fairly easy and inexpensive to pick up. You can order it online or at some craft and plastics stores. Any RTV (or Room Temperature Vulcanizing) silicone will do. For this process the Polyester casting resin I will be using has some cure inhibition (meaning that it will remain sticky) against tin cure silicone (your standard inexpensive RTV). This means that to get good parts out of the mold, you will have to coat the mold in sealant before casting your parts, bake the parts after they're cured, or apply a clear sealant to the parts after they are molded.
- Latex Gloves
- Stirring sticks
- A digital scale or graduated measuring cups
- Bondo car body filler. You can pick this up at most hardware stores and auto shops.
- Clear Polyester resin. Find it at a plastics store, or order it online. Sometimes craft stores will sell this as a way to make cutesy paperweights with flowers trapped in them, etc.
- MEKP catalyst. This will often come with your resin. You can also find it as fiberglass catalyst in most hardware stores.
- Polyester resin dye
- Respirator, ventilation system, or open well ventilated space to work in. Be mindful of your neighbors, as the polyester resin smells something awful, and will cause some people with sensitivities to feel ill.
- Hot glue
- A mold board. Any piece of smooth wood or plastic will do. Remember to seal the wood before casting on it, or else the mold will be difficult to remove.
- Disposable paint brushes
- Plenty of paper towels
- The touch
- The power