LOCTITE^® 518 is specifically engineered for sealing close-fitting metal surfaces in the presence of slight surface imperfections. When confined between two metal flanges, it cures in the absence of air and creates a flexible, pressure-resistant seal. This product prevents leakage and ensures reliable performance in applications involving compressed gases or liquids. LOCTITE^® 518 remains effective on most active metals (iron, steel, copper) and even on passive substrates like stainless steel or plated surfaces, albeit with a longer cure time. Its flexibility to seal slightly contaminated surfaces, such as those with oil residue, makes it harsh industrial environments.