Ignoramus26696 wrote:

The boat trailer guide base that I made today is made of mild steel
that I painted with rustoleum (thanks to advice received here).

http://igor.chudov.com/projects/Trailer-Guide/

A concern expressed here was that when it contacts galvanized pipe or
trailer frame, it may start to corrode quickly due to interaction of
steel and zinc.

This is horse pucky of the most irritating variety. Zinc corrodes preferentially
to steel, that's why they melt the zinc and dip steel in it. That's called
galvanizing. Duh.

Put steel next to aluminum or brass? Problem. Next to zinc? No problem.

GWE