Adriatic posted:JHZ, You want "etching primer" for the galvanized (automotive supply or painter's supply house), cost is higher; but great stuff. (kinda hard, so hard to sand too. Go light and easy; no runs, etc.) Everything else will eventually chip or peel. Etching primer chemically treats and binds to the zinc (or other hard to paint metal too like brass, copper, etc.) You either didn't clean with a solvent, didn't allow full cure, or didn't use compatible paints. (unusual for a topcoat to react to a primer... is that the case?... If so, brands type& color please....so we don't repeat it )
Thanks for the info.
I think there must have been a small spot on the primer that didn't take, about the size of a dime. After that the paint job was already ruined so I had nothing to lose. I wiped the area with a paper towel and hit it with the top coat again. It just got exponentially worse after that.