Loctite thread sealants loctite 1545634 loctite 5400 is designed for locking and sealing metal pipes and fittings as well as other cylindrical metal assemblies it ensures an instant low pressure seal for metal pipes and fittings at low temperatures it will not creep shrink or block systems by shredding its key differentiator is the white material safety data sheet loctite 5400 carries no hazard symbols risk or safety phrases and does not contain any declarable carcinogens mutagens