For example, an exhaust manifold gasket on a car engine requires resistance to much higher temperatures than on the intake manifold. Other composite gaskets are engineered to resist specific fuels and chemicals they will contact, such as propane, diesel fuel, alcohol, or transmission fluid. Regardless of their construction, all gaskets must provide some degree of temperature, pressure, and chemical resistance. Additionally, they must provide radial strength to help the gasket withstand differential motion between mated surfaces. And most importantly, the gasket must maintain its seal under any and all of these conditions.
Composite gaskets come in a variety of constructions.
Once the gasket body is complete, it is diecut to the desired shape, featuring openings for mechanical connections and fluid channels between components. Flange lacing and grommet holes may also be diecut or formed on the gasket to enhance its sealing characteristics. The composite may then undergo a flattening process to ensure that it doesn't exceed a specific thickness. For some applications, however, these materials and manufacturing methods are still not enough. Often elastomeric coatings must be applied on gasket surfaces to further enhance sealing characteristics.