Having perused the preserved wisdom of this board going back to 1997,
what's the best way to keep Mr. Rust from doing the nom-nom-nom on my
carefully-crafted 4130 fittings?

Thanks to my friendly neighborhood college-chem-lab person I can dip
them in phosphoric acid (with all appropriate safety precautions) to
kill any surface rust, but then what?

Cad plating is expensive and environmentally unfriendly. Zinc
Chromate primer seems to be better suited to aluminum than steel.
Just shoot them with a rattlecan of Rustoleum? (I can almost hear
R.S. Hoover saying, "Go ahead if you want, but I'm not flying in it.")

Is a 2-part auto epoxy still the way to go?