Gasket in the siphon cover – A large diameter seal for a sink or wash basin siphon can be quickly cut from a piece of polyurethane foam, what remains after laying the floor panels, or from a piece of cork board. Finally, thick cardboard soaked in oil can also be used. An old gasket can be used as a template for the shape to be cut. Let's remember, that such a gasket will, however, be less durable than the factory gasket.