LOCTITE® SI 5990 is a non-corrosive, oil-resistant, moisture-curing gasketing sealant, ideal for copper and applications involving large gaps. It can also be used for electrical insulating applications and is compatible with various surfaces, including metals and plastics. LOCTITE SI 5990 cures when exposed to moisture in the air to form a rigid rubber gasket. Its thixotropic nature makes it easy to apply and reduces sealant migration after application. LOCTITE® SI 5990 is label-free and offers excellent adhesive strength, even at temperatures up to 350°C (662°F).