RTV is an acronym for "Room Temperature Vulcanizing" silicon, meaning it dries at room temperature. RTV is a rubber polymer. Similar to epoxy, it is made of the base rubber material plus a curative that is activated by exposure to air. The best-known use of RTV silicone is as a sealer in home construction. But the properties of this versatile material make it ideal for many applications.
RTV silicon is a very common building sealer, especial in kitchens and bathrooms. Most caulking is made of RTV silicon or contains RTV silicon. It lends itself particularly well as a sealer because it is water repellent, adhesive and holds it shape.
Adhesive and Gaskets
RTV silicon is not an extremely strong adhesive. However, it has a unique combination of mild adhesive properties and rubber properties. The combination can create a gasket-like adhesive that can be used in many applications to "glue" two surfaces and provide a small amount of cushion, such as two pieces of marble countertop. RTV is also used specifically for gaskets. High-temperature additives are used in some RTV sealers for use in engines as a gasket/sealer.
RTV silicon's unique properties are well-suited to mold-making. Its transformation from a jelly-like, semi-liquid to a rubber allows it to be poured around objects to make molds or applied to objects to make molds. When items cast in RTV molds are removed, such as plaster figurines, the rubber properties are very helpful. They stretch and contort, allowing for extraction, then return to the identical shape.
A variety of craft projects use paper glue, wood glue, paste and other adhesives. RTV silicon is another light-duty adhesive well-suited for crafts. It doesn't have strong or harmful odors. It has many properties other craft adhesives don't have. For example, most craft adhesives are water-based and shrink as they dry. They may also be opaque when wet and dry translucent. RTV silicon maintains its shape and translucence as it dries.