What is Silicone Sealant?

Silicone sealant or adhesive is a powerful, flexible product that can be used in many different applications. Although it is not as strong as some other sealants or adhesives, silicone remains very flexible, even once it has fully dried or cured. This type of sealant can also withstand very high temperatures, making it ideal for applications that suffer high heat exposure, such as on engine gaskets. It also comes in a variety of forms.

One way to buy silicone sealant is in a two-component addition; this type of product requires the user to mix two compounds to make the sealant. The mixture must be made immediately before using it, which makes it rather tricky to use. It's also available as a single product, with no mixing required. One type is called Room Temperature Vulcanizing (RTV), which starts to cure as soon as it is exposed to the air — or, more precisely, the moisture in the air. Because of this, it must be used quickly.

There are a variety of other, more technologically advanced forms of silicone sealant as well. One type, called pressure sensitive sealant, has a permanent tackiness and adheres with deliberate pressure. In other words, although it will always be “sticky,” it won’t stick if something simply brushes or rests up against it. Another type is called UV or radiation cured sealant, and it requires ultraviolet light to cure it. Thermoset silicone sealant requires exposure to heat in order to cure.