R-2128, R-2138 and R-2157 Bases & Activators are Platinum Cured (Addition Cure), two-component, room temperature curing (RTV) silicone rubbers designed for general mold making. These systems are low in viscosity and exhibit high Physical profiles. Use molds to cast polyester, urethane, epoxy, low melt metal (600F), thermoplastics (Polyvinyl), wax, soap, plaster, and any material where a release free casting is required.