Bondo Fiberglass Resin is an industry standard for restoration and repair of vehicles and boats. The high strength polyester resin features a waterproof formula, is highly durable and provides long-lasting repairs.Bondo Fiberglass Resin is a strong material commonly used for autos, boat building and other repairs. This high-strength polyester resin can be used with fiberglass mats or cloths on surfaces including fiberglass, wood, metal and masonry to repair metal rust-outs and to recreate or join surfaces. It can also be used by itself as a wood or concrete sealer. It accepts nearly any paint system.