The author describes a field and laboratory investigation of a premature failure of a fluoropolymer coating system on a galvanized steel roof. Both the failure and the solution provide lessons in chemistry and physics....
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We supply quite a lot of fluoropolymer coating for gal but believe you must have a barrier coating of MIO epoxy or similar to keep out moisture which starts an electrolytic reaction under the coating. This reaction will eat away the zinc causing red rust to break out.
Comment from Jay Helsel, (5/16/2013, 2:54 PM)
Coating manufacturers typically recommend specific primers for their fluoropolymer coatings, some of which are epoxy materials