PlatSil 73-40 is a mid-range hardness (A~40) platinum silicone rubber designed for making long-lasting, flexible molds to cast liquid plastics or rubbers (polyurethanes, polyesters and epoxies) as well as polyurethane foams. PlatSil 73-40 can also be used to cast waxes (foundry applications or candles); plasters (gypsum or fiber-reinforced gypsums); soaps; and all varieties of concrete (wet-casts, glass-fiber reinforced concrete-GFRC). Since PlatSil 73-40 has no shrinkage upon curing and resists mold distortion due to casting, it is an ideal product where dimensional stability is required. PlatSil 73-40 is a 1A:10B mix and has a yellow-colored Part A for easily identifying when material is properly mixed. PlatSil 73-40 also has Polytek’s signature high, knotty tear strength and offers excellent chemical resistance and elongation as well. As with all Polytek silicone mold rubbers, PlatSil 73-40 allows casting to be done without release agents.