3M MARINE 4200 ADHESIVE/SEALANT A one-part, general all-purpose polyurethane that chemically reacts with moisture to deliver flexible bonds with good adhesion to wood, fiberglass, gelcoat, plastics and metals. Paintable and sandable. Forms watertight, weather-resistant seals on joints and boat hardware above and below the waterline. Note: For very high strength or unremovable bonds, use 3M 5200 sealant. Not recommended for sealing wood decks.