Your choice of mold material is based primarily upon which casting material you plan to use and how many castings you wish to produce. Polyurethane mold rubbers are excellent for casting concrete, plaster, wax and limited resins and are very economical. Silicone mold rubbers are the best choice for reproducing numerous resin castings (polyurethane, polyester, epoxy) and polyurethane foam parts. Silicones are more expensive, but have greater chemical resistance and longer mold life when resin casting. Latex mold rubbers are used primarily to create molds for casting decorative concrete statuary and are generally less popular due to the length of time required to make the mold. Polyurethane and silicone rubbers are most popular as molds can be completed within a day!