At times the stripper won't remove all the base color and sealer so if there's just a little left just stop there and 180 or 220 it off.If you have knarley looking welds I stay off these,along with the rivets and the rolled fender flanges-basically anywhere the stripper can get down into crevices and give you a hard time neutralizing it.I run these areas through the blast cabinet or a hand blaster to finish stripping.If you blast make sure you seal up the openings in the tank 3 times better than you think you need to.