Priming can be a contentious issue amongst homebuilders. Whether or not to do it in the first place, how extensively to do it, what materials to utilize in the course of doing it, etc.
On my first RV many years ago, I primed nearly every interior surface with zinc chromate. Over the years, I’ve realized that my old approach was complete overkill. I’ve seen many airplanes over a half-century old with little to no corrosion. Consequently, my new RV will be primed (with self-etching, rattle-can primer) wherever I think appropriate. I won’t be doing most skins or other large, Alclad surfaces, but will be doing small components, non-Alclad parts, and (of course) any non-powdercoated steel.
