On Sun, 18 Oct 2020 09:58:20 -0400, Paul wrote:
Try keywords like "wash primer".

I've not used any, because I'm the guy with the galvanized surfaces with
no paint on them :-) I can tell you with authority, that regular paint
lasts around a year,
before the lack of adhesion makes it come off again.

Hmmm... we had new railings put up around 4 years ago. They were
galvanised and spray painted before fitting. Nothing special about the
paint other than it being thinned to be able to spray it. Apart from
weathering of the paint its still sound. They are ready for a paint next
year though.