Mold Star 30 Silicone Mold Making Rubber - Trial Unit Pourable platinum-cure silicone rubber with Shore 30A Hardness 45 min. pot life / 6 hour cure Easy to Mix: mixed 1A:1B by volume (no weighing scale necessary) Good for casting wax, gypsum, resins, concrete and other materials Heat resistant up to 450F (232C)