A project of mine in the contemplative stage will probably require
joining a piece of brass to a piece of steel (about 1/2" thickness
each). Both will then be exposed to the elements. At this point
bolting them together seems the only realistic option (1/4"-20 or
5/16"-18, not written in stone). My main concern is the electrolytic
corrosion likely to result from the contact between the dissimilar
metals.

What would be the best way to minimize this? There are a few
permutations I have thought of:

1) Drill a hole through both and bolt together with stainless steel
nut and bolt.
2) Same, but use a brass bolt and nut.
3) Braze (:-0) a piece of brass thread to the brass part, hole through
the steel bit and a brass nut.
4) Thread the brass piece, hole through steel and use a stainless
steel bolt (no nut).

etc. etc.
Does thread locker protect from such corrosion?

The steel part will be painted with POR15.

Thanks,

Michael Koblic,
Campbell River, BC