Loctite 510: Gasketing Product- high temperature and chemical resistance. Ideal for use on rigid flanges Loctite 515: Gasketing product for machined metal flanges. Medium strength. For gaps up to 0.25 mm. 30 min fixture time Loctite 518: Medium-strength, general purpose gasketing product - excellent contamination tolerance. Ideal for use on casted iron, steel and aluminum flanges. Loctite 573: Surface sealant- slow curing. Ideal for sealing of machined, rigid metal flanges. Loctite 574: Gasketing Product - general purpose. Ideal for use on machined and rigid metal flanges.