A fast curing, one-part polyurethane that chemically reacts with moisture to deliver strong, flexible bonds to wood, gel coat and fiberglass. It forms watertight, weather-resistant seals on joints and boat hardware above and below the waterline. In addition, its flexibility allows for dissipation of stress caused by shock, vibration, swelling or shrinking. - 3M marine adhesive/sealant Fast Cure 4200FC white bonds and seals fiberglass, gel coat and wood. Ideal for rub-rails, stern-joints, deck and through-hull fittings and access plates. Medium strength allows for disassembly.