Ive done quite a few exhausts with the 2,000 degree stuff at auto parts stores, usually I wirebrush it with a wirewheel, clean it real good with some acetone, put a few coats of the paint on then install it and get the pipes nice and hot. It says your suppose to bake it on, I never have I always let it dry normally, then very carefully reinstall it and never had a issue. I painted the exhaust tips on my daily driver f150 and the paint lasted over a year until I traded it in.