Mold Star 15 Slow is an easy-to-use platinum silicone which is mixed 1:1, no scale necessary. Featuring relatively low viscosities with a pot life of 50 minutes and a cure time of 4 hours at room temperature. Mold Star cures to a soft, strong rubber that are tear resistant and exhibit very low long term shrinkage. Good for casting wax, gypsum, resins, concrete and other materials. Cured Mold Star is heat resistant up to 450??. Please see the Smooth-On website for more information.