For making fast brushed rubber molds that have the best release properties for production casting of resins, plaster, etc. it is a tin silicone rubber that self-thickens for making concrete brushable -on molds . Properly applied, Mixed 100A:5B by weight, rubber quickly develops thixotropy when mixed in air. Cured with negligible shrinkage to a durable mold rubber good for production casting resins, foams,concrete, plaster and other materials. Including reproducing sculpture, architectural restoration, making candle molds, casting pewter, etc.