Bondo® All-Purpose Fiberglass Resin is your go-to material for sealing cracks, repairing breaks or filling holes in fiberglass, wood, concrete or metal. Along with cloth tape or matting, this 100% waterproof resin can be used for hundreds of repair projects to include cars, trucks, pools, showers, boats and more. This waterproof, two-part resin includes liquid hardener. Bondo® All-Purpose Fiberglass Resin is your go-to material for sealing cracks, repairing breaks or filling holes in fiberglass, wood, concrete or metal. Along with cloth tape or matting, this 100% waterproof resin can be used for hundreds of repair projects to include cars, trucks, pools, showers, boats and more. This waterproof, two-part resin includes liquid hardener.