[Cuz]

I would strip the paint and use a good protector polish instead of painting it again. Stainless metal will not cause any damage. It not the screws fault unless they're alumimun. Aluminum gets corroded very easily. If you do paint the frame again make sure you use an expensive aluminum primer first on both sides. Then a real good aluminum paint. Spaying is better than brushing. Or you can take the frame to a metal shop for a professional job that will last forever.