TinSil 70 Series RTV Silicone Rubbers are condensation-cure, tin-catalyzed, flexible mold rubbers. TinSil products consist of a liquid Part B base and Part A accelerator, which, after mixing at the proper ratio by weight, cure at room temperature to rubber with a tough, knotty tear property. TinSil molds have easy release properties and are resistant to high temperatures. TinSil molds are excellent for casting polyesters, epoxy and polyurethane resins; waxes and many other materials. As with other Polytek® elastomers, the last two digits in the product name indicate the approximate Shore A hardness of the cured rubber.