GI-Series (Tin Catalyzed) Condensation cure two-component silicone rubbers are excellent for most general mold making and prototype applications. The GI rubbers are not sensitive to inhibition, meaning they will cure at room temperature over virtually any surface. They are easy to mix and de-air, and they cure with only a slight degree of shrinkage. The speed at which the rubber hardens can be accelerated with special activators. Finished GI silicone molds are excellent for casting polyester, epoxy, polyurethane, masonry, gypsum and candle wax.