First off, I am NOT an experienced painter. In spite of that, a friend has asked me to help him repaint the roof on his '35 Ford coupe. He believes it's lacquer and is flaking. Does the old paint have to be completely removed to bare metal? What kind of primer/paint would be best to use here? There will be blending where the roof line meets the body so we'll be painting over some lacquer there at a minimum.