Castin'Craft Mold Builder 16oz- A natural liquid latex rubber used to create highly detailed reusable molds from metal, clay, plaster, wood, plastic or glass. Coat brass or copper with an acrylic lacquer or shellac, and seal porous materials, like clay, plaster and wood, with a paste wax. Quick drying, fast build up, peels easily from model, is flexible and stretchable, and is harmless to most surfaces! Cast paper, plaster, candle wax, soap, casting resin or casting epoxy in the he molds you make.