LOCTITE 638 is a high strength, fast curing, general purpose retaining compound. LOCTITE 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching 0.25 mm. The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration. It not only works on active metals but also on passive substrates, exhibiting robust cure performance. The product offers high-temperature performance and good oil tolerance, and tolerates minor surface contaminants. Tolerates minor contaminants, including industrial oils High strength on all metals, including passive substrates (e.g. stainless steel) High temperature resistance Ideal for shafts, gears, pulleys and similar cylindrical parts DVGW Approval (EN 751-1): NG-5146AR0619 P1 NSF Reg. No.: 123010 WRAS Approval (BS 6920): 0511518