Interlux Watertite Epoxy Filler is a two-part, fast-drying epoxy compound for filling holes and repairing scratches in fiberglass and gelcoat. It can be sanded, once cured. You must overcoat Watertite with VC Performance Epoxy, Interlux Epoxy Primekote, InterProtect 2000E/2001E, or InterProtect HS Epoxy Primer. Do not apply gelcoat, topside finishes, polyester, or vinyl ester materials directly over Watertite Epoxy Filler.