Getting ready to paint up a 500 gal tank. I left the original paint (I believe it's powdercoating or some high strength epoxy) and just grinded down the areas I needed to weld. Can I paint over the existing, or should I remove down to bare metal? Second part- short of mechanically removing (grinding), what's the best way to remove? I've tried zip strip (my go to for paint removal), and jalco thinking the tank was epoxy paint, and neither even blemished the surface. Suggestions?