Prior to surface preparation of any kind, all bare fiberglass to be painted must be thoroughly washed. Fiberglass Dewaxer is a special blend of solvents, formulated specifically to cut through and remove mold release, grease and previously applied wax from the gelcoat. Regardless of the boat's age, the initial washing is imperative - residual parting agents, utilized by the manufacturer to pop the boat from the mold, may still be present, although not visibly apparent. Although the fiberglass will be slightly etched by the strong solvents in Fiberglass Dewaxer, the surface must be sanded - or a coat of Bottom Prep Sandless Primer applied - before painting.Coverage: approximately 400 ft per gallon, depending upon number of applications