DuPont SP11C specification is the corporate engineering standard for fluoropolymer-coated fasteners that require excellent corrosion resistance. DuPont SP11C is a specification for fasteners that are intended for use in severe atmospheric corrosive environments. It is not recommended for use in immersion service. The coating system is comprised of two coats: a sacrificial base coat of electroplated zinc or ceramic/metallic coating, and a fluoropolymer top coat applied by an applicator qualified by DuPont. Since fluoropolymer coatings have a low coefficient of friction, the make-up torque values for fasteners coated according to SP11C will be reduced.
The DuPont Teflon industrial coating 857G product line is a new technology targeting applications requiring anti-galling and dry lubrication. It is a water-based, low VOC, easy-to-use coating offering outstanding corrosion resistance that can be applied at .0005 to .0045 inches thick by conventional spray or dip spinning. The performance test ASTM B117 showed less than 10% rust on fasteners coated with 857G-018, the blue version of these coatings, after 3,000 salt spray hours. VOC emissions were less than 3.0 pounds per gallon. There are several coating color options.
"Getting the DuPont 857G coating line included on SP11C took years of development and testing. Its inclusion on the specification in May of 2013 should indicate to the coating and corrosion engineering communities the robustness of this coating," said Chris Dohl, vice president of Intech Services.