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Specialty Sealants

3M™ Aerospace Sealant AC-251 Black Class B - Moldline and Canopy / Windshield Sealant

AC-251 Class B Black is a two-part, quick curing, polysulfide based canopy and windshield sealant. This product is formulated for sealing of acrylic, glass, and polycarbonate aircraft canopies and windshields. AC-251 Class B Black contains no solvents and does not craze. The sealant quickly cures and exhibits excellent adhesion and resistant to UV and weather exposure. AC-251 Class B Black has a thixotropic, non-sag consistency. It can be readily applied with a spatula or extrusion gun on vertical surfaces.

AC-251 Class B (Black) - Moldline and Canopy / Windshield Sealant Technical Data Sheet (PDF, 94 Kb)

3M™ Aerospace Sealant AC-251 Gray Class B - Moldline and Canopy / Windshield Sealant

AC-251 Class B Gray is a two-part, quick curing, polysulfide based canopy and windshield sealant. This product is formulated for sealing of acrylic, glass, and polycarbonate aircraft canopies and windshields. AC-251 Class B Gray contains no solvents and does not craze. The sealant quickly cures and exhibits excellent adhesion and resistant to UV and weather exposure. AC-251 Class B Gray has a thixotropic, non-sag consistency. It can be readily applied with a spatula or extrusion gun on vertical surfaces.

AC-251 Class B (Gray) - Moldline and Canopy / Windshield Sealant Technical Data Sheet (PDF, 94 Kb)

3M™ Aerospace Sealant AC-645 B-2 - Low Density, Hole Filling, Cavity Sealant

AC-645 Class B is a low density, two-component, manganese dioxide cured liquid polysulfide polymer system. It is suitable for use in fuel tank, fuselage hole filling, cavity filling and fuel tank filleting applications. It has outstanding resistance to jet fuel, as well as resistance to chemicals and petroleum products common to the aircraft industry. AC-645 Class B maintains its flexibility and bond strength on most metal substrates such as aluminum, titanium, steel, stainless steel, and many coatings under the extremes of temperature, weathering and stress. The mixed compound is a thixotropic paste easily applied by extrusion gun or spatula. It has excellent tooling properties.

AC-645 Class B - Low Density, Hole Filling, Cavity Sealant Technical Data Sheet (PDF, 91 Kb)