First attempt at weathering not gone so great. I stipped the paint off the top slide of a pistol and painted 5-6 coats of nuprol UFP allowing a day between each coat for it to dry. When sanding down the edges of the slide the paint is coming off in small flakes giving a jagged edge to the weathering. The lower of the pistol, with it's factory paint, is much tougher and not flaking at all and lets me get some very neat fine weathering. What did I do wrong? Should I have used a primer?