RTV Silicone

rtv silicone


Though first developed in the late 1930’s Room Temperature Vulcanizing or RTV silicone was created to be an insulating material that could withstand the heat produced by smaller engines. Still used in the electronic industry for potting and encapsulation, it is now primarily used to make durable, flexible, and easy to use molds suitable for a wide range of casting materials.

The entertainment industry was transformed by the scenes and characters that now come to life on thanks to the development of RTV soft “skin” silicone rubbers. Platinum cure silicone is also used in the medical field for prosthetics and other specialized uses.

In addition to making strong, flexible custom resin molds that perfectly replicate the original artifact down to the most intricate details, the molds cast with it have good elongation and tear strength and excellent directional stability. RTV silicone is available in both condensation (tin catalyzed) and addition cure (platinum catalyzed) formulations, both of which are comprised of two-components which must be mixed for activation.

The two components of RTV silicone are usually referred to as Part A (silicone component), and Part B, (catalyst component). Both liquid, Part B, the catalyst, is usually of a different color— when the color is consistent and has no more streaks in it, it is fully mixed.

It is always a good idea to fully read the manufacturer’s instructions and complete as much of the mold-making construction and process as possible before mixing the two components since the open time is fairly short, anywhere from 30 minutes to 2 hours.

ResinObsession carries a full line of easy to use RTV silicone rubbers which do not require vacuum degassing with varying open and demolding times to suit the time requirements you may have in your custom mold-making projects, and Cindy, the ResinLady, to answer your questions.