Loctite thread sealants loctite 135503 loctite 586 is a high strength sealant for locking and sealing metal pipes and fittings as well as other cylindrical metal assemblies it cures slowly and provides a high pressure seal for metal pipes and fittings loctite 586 exhibits excellent characteristics on brass and is also suitable for copper it will not creep shrink or block systems by shredding loctite 135503 586 thread sealant high strength copper amp brass 50ml