Expanded graphite gaskets are comprised solely of pure expanded graphite. It makes an excellent gasket material is it is higly compressible, conforms to the flange surface and has superior chemical resistance. Since graphite is a natural conductor, it has a low electrical resistance. However, pure expanded graphite gaskets have little mechanical strength which creates a concern for handling. These gaskets are typically brittle since the layers of graphite material within its structure are very lightly held together. Any force that is great enough will separate and fracture the integrity of the layer of graphite and damage the shape of the gasket.
Some expanded graphite gaskets have a steel foil or tang or a corrugated metal core to help improve the gasket's mechanical strength.