[pinner]

About 3 years ago I painted my brothers 12' aluminum car topper, I cleaned prepped and applied grey etching primer that comes in rattle cans. The boat has been in storage since then. When I went to pick it up the paint is flaking off to the bare aluminum everywhere on the outside "which never had paint from the factory" but the paint on the inside of the boat "which had paint from the factory" seems fine.
So obviously the prepping I did to the outside was not sufficent, so im in the process of sanding off the remaing paint on the outside and starting over. My new process will be sand, 50/50 vinegar wash, prime with zinc chromate then top coat. So heres my questions for any that can answer.
How light of a coat do you put the zinc chromate primer on?
Should I lighty sand and zinc chromate primer the inside where the paint is not peeling, or just light sand and top coat?
Is the vinegar wash mopped on then rinsed with water?
Thanks

[gcboat]

The zinc chromate is applied very lightly. Almost a 'heavy dusting' - .
The ole' vinegar trick is really not needed anymore. With the advent of all these etching chemical sprays, etc. it's a step that isn't needed. Not saying that you can't do it - just not necessary. And no, I wouldn't apply the zinc primer over sound paint. Just a good cleaning, some light sanding and do your top coat.
The zinc primer should have at least 24 hours to bond before applying your finish coat. Folks sometimes confuse bonding time with drying time - big difference.