3M Marine Adhesive Sealant 5200 WHITE CAULKING. A permanent solution for bonding marine substrates like wood, fiberglass, and metal, this high-performance polyurethane adhesive/sealant becomes tack free in 48 hours, completely cures in 5-7 days with no shrinkage. Tough yet flexible polyurethane polymer is ideal for deck housings, hull fittings, porthole mounting, fiberglass transoms, and underside molding. Sold by the 10 oz cartridge.