3M Aerospace Sealant AC-770 Class B are fast cure, low density two-component, manganese dioxide cure, polysulfide fuselage sealants. 3M AC-770 Class B Sealants have outstanding resistance to aviation gasoline and jet fuel, as well as resistance to chemicals and petroleum products common to the aircraft industry. 3M AC-770 Class B Sealants maintain flexibility and bond strength on most metal substrates like aluminum, titanium, stainless steel, steel, and many coatings under extremes of temperature, weathering and stress. The mixed compound is a thixotropic paste easily applied by extrusion, injection gun or spatula. They have excellent tooling properties.Information provided by 3M |