Polyurethane rubbers are fast gaining popularity as the mold making and lifecasting rubber of choice for mold makers and hobbyists alike. The physical and performance superiorities of these polyurethanes against the rasping action of concrete mixes make them ideally suited for concrete castings. In fact, polyurethane rubbers outperform all other rubber type materials even in mechanically abusive environments. Therefore, it is suitable for a variety of molding and industrial applications.