Aiming to repaint the 17" tantrums that ive got. The person who gave them to me sandblasted them and then coated with rustoleum (gunmetal color) and sprayed them with some clear coat. There are a few bubbled spots as well as scratches in some areas. THe problem is that they scratch very easily and need to be refinished with something that'll hold up better. I dont want to have to take them off and repaint again. I want to do it a gunmetal color so give me some advice on what to use. THanks