Lost-wax casting, a process where the original wax model is "lost" during the fabrication of the bronze original, dates back 2,000 years ago to early Egypt. Weitzman Studios, Inc. uses investment molds in their lost-wax process. The original pattern is created with clay, plaster or another material. A rubber mold is formed from this original. A thin layer of molten wax is used to coat the inner layer of this rubber mold. The entire mold is then coated with investment, which is a fireproof material. Molten bronze, which is an alloy of copper and tin, is poured into the mold. The wax melts and the bronze replaces it. Once the bronze solidifies and the outer layer of clay is removed, the original bronze sculpture remains.