Hercules 15707 Pipe Thread Sealant Block Putty, 1/2 Pt.All purpose, tough, pliable seal for joints, valves, flanges, and gaskets puts joints into service in minutes. An excellent gasket seal sets up quickly and dries to form a very tough, yet flexible seal which will not harden, crack, crumble or shrink. Seals old or worn fittings. Ideal for pumps, tanks and equipment carrying steam, water, oil, gasoline, fuel oil, hydraulic fluids, natural and LP gas (vapor state), anti freeze, refrigerants except