Room Temperature Vulcanizing or RTV Silicones are catalyzed mold making silicones that have natural non-stick properties and are capable of reproducing the finest detail. They are available in two forms;
Condensation (Tin) Cure silicones are very resistant to cure inhibition from the materials they are cast against. They may inhibit the cure of polyurethanes cast into molds made from them.
Addition (Platinum) Cure silicones are prone to cure inhibition from the material they are cast against, but do not effect the cure of resins cast into molds made from them.
Addition cure RTV silicones should not be cast against substrates containing Sulphur, such as sculpting clay or some natural rubbers. A Condensation Cure should be used or a barrier coating applied in these applications to avoid cure inhibition issues.