When it come to gasket selection, there is no real wrong choice; it all depends on the application. Non-metallic gaskets are chosen for flat faced applications with low pressures. Metallic gaskets are fabricated from one or a combination of metal to the designed shape and size. They are suitable for high pressure and temperatures applications where there is a high bolt load to seal.
Non-Metallic Gasket Materials
Non-Metallic or soft gaskets are made from various materials such as: rubber and PVC materials, non-asbestos. PTFE materials and carbon / graphite materials. These materials have a wide range of properties including heat resistance up to 5000F; the following guide will help you pick the general class of materials suitable for your application. These materials are available in uncut form as well as in the form of gaskets.