LOCTITE® 638™ is a high-strength, green, urethane methacrylate-based anaerobic retaining compound for bonding cylindrical parts. It cures in 4–72 hours (4 min fixture time) on metals, including passive substrates and stainless steel, filling gaps up to 0.25 mm. It resists temperatures up to 180°C and oils, with high shear strength .
