SILASTIC™ RTV-3481 Mold-Making Rubber is a two-part material consisting of  SILASTIC™ RTV-3481 Base which when mixed with a SILASTIC™ RTV-3081 Mold-Making  Curing Agent, cures at room temperature by a condensation reaction. A range of materials  can be cast into the cured silicone mold: plaster, polyurethane and polyester resins are  materials typically used.