Metal was prepared by sandblasting so it was perfectly clean. Used the Extreme Chassis Black primer and waited the recommended 24 hours prior to top coating with the gloss. After 48 hours, the paint is hard as nails and look fantastic. I'm very impressed with this product. Like any paint work, the end results are dependent on the prep work so I don't know what would happen if you don't follow the directions, if you do, it will look great.