le part polyurethane varnish ideal for sealing damp porous surfaces prior to using release agent. Used as damp proof floor sealing, pond sealing, sealing concrete prior to GRP sheathing where alkali in concrete can react with resins. Also an ideal coating for plug surfacing before taking mould as release agents and resins do not attack G4. Also used to improve the bond of GRP to metal. Withstands temperatures up to 200 C with good chemical resistance.