PolyCoat Sealer & Release Agent

For Mold Making: Apply PolyCoat to porous (may require multiple coats depending on porosity) or non-porous models when making polyurethane and platinum-cured silicone rubber molds (not recommended for use with liquid tin-cured silicone rubber). Since PolyCoat leaves a dry, cured silicone coating on a surface, it may be used without additional release agent. This can be quite advantageous when making a polyurethane rubber mold as no residual release will transfer to the cured mold surface from the mold making process.

For Casting: PolyCoat can also be applied to aging PlatSil^® and TinSil^® silicone molds to improve performance (easier demolding) and extend their useful life. In addition, PolyCoat can be applied to firm polyurethane rubber molds to give them a thin silicone skin on the mold face. This can allow materials such as polyurethane plastics or foams, that would ordinarily require releases, to be cast into dry polyurethane molds at a reduced cost. NOTES: Cure time varies between 30 minutes and 16 hours depending on temperature, humidity and porosity of the model; ensure that PolyCoat has completely cured before applying liquid rubber or plastic. Very porous surfaces may require multiple coats of PolyCoat, applied ~15-20 minutes apart. Care should be taken to adequately seal the surface, but not over-apply; as with other sealers, surface details on the model can be lost when a sealer is over-applied. When brushing, be careful not to leave brush marks on the surface as the PolyCoat begins to gel. One common technique used when either brushing or spraying is to apply the PolyCoat then flip the master over to allow excess to run off. This leaves a thin coating behind and helps to eliminate brush marks or surface defects. Do not use PolyCoat to seal plaster. Gypsum models tend to aggressively wick the solvent into pores and the curing process can be slow or incomplete, leaving some residual solvent behind, which may interfere with the cure of certain rubbers.