A gasket provides a barrier against fluid transfer across mating static surfaces. Proper selection depends on how well the gasket material meets four basic requirements.
Although many material combinations are suitable for gaskets, the most common are cork compositions, cork and rubber, plant and vegetable fibers, rubber, plastics, and paper. Flexible plastic foams and elastomeric sponge are coming into use, as is flexible graphite. Formerly, asbestos was widely used.
These materials are often laminated with each other to combine the properties of a strong but relatively incompressible material with those of a highly compressible but weak material. For example, cork composition and vegetable fiber are often laminated together; depending on end use, either may serve as the center filler.