Loctite gasketing sealants and compounds loctite 311791 loctite si 5970 is a silicone sealant that cures on exposure to moisture in the air to form a tough rubber gasket it has been designed primarily for flexible flange sealing and is ideal for use where high vibration or flexing occurs loctite 5970 is tack free after just 25 minutes and can be used on machined or cast metal or plastic and painted parts loctite 311791 si 5970 gasketing product good oil resistance 50ml