Mold Star rubbers are easy to use platinum silicones which are mixed 1A:1B byvolume (no weighing scale necessary). Mold Star silicones feature relativelylow viscosities and vacuum degassing is not required for most applications.Mold Star silicones cure to soft, strong rubbers which are tear resistant andexhibit very low long term shrinkage. Molds made with Mold Star will last along time in your mold library and are good for casting wax, gypsum, resins,concrete and other materials. Cured Mold Star rubber is heat resistant up to450F (232C) and is suitable for casting low-temperature melt metal alloys.Note: THI-VEX is NOT compatible with Mold Star rubbers. MOLD STAR 20T: MIXRATIO: 1:1 by volume; POT LIFE: 6 minutes; DEMOLD TIME: 30 minutes; SHORE A:20; COLOR: Transparent Read the MSDS before using. Consult the TechnicalBulletin for further information. Adult Supervision Required. Keep Out of theReach of Children.