Raw finish with gun blue?
 

Not a huge fan of raw finishes myself but some people seem to want them. I've heard that corrosion under the clearcoat is an issue because of the lack of a primer.

Has anyone tried selenious acid, followed by clear coat? This is the stuff known as "gun blue" that is supposed to form one of the other iron oxides that isn't rust (magnetite I think) which makes a protective layer a bit like mill scale. You then usually put a bit of oil on it which is supposed to kind of soak in to the surface but I was thinking clearcoat instead.

Maybe I'll try on a couple of offcuts and leave them out in the British winter for a bit.

people have used just gun blue. It lasts for a while. I only vaguely remember reading about powder over gun blue, but I don't remember how it came out.

the car world has gone nuts and raw finishes are popular right now. I did a little research on what finishes they are using, but nothing struck me as something I wanted to use. But it is possible to have a raw finish

I've gun blued (of the two methods I know of I did the cheaper "cold" version, brushed on special fluid and wiped off) a few items and regularly Navel Jelly my bare frames during construction delays. The bluing is a bit tougher and resists rust better but both suffer the same cancer just at slower rates.

I would very strongly suggest experimentation as both of these coatings can vary in look depending on how they are applied. Andy

There are various type of steel "bluing" but I assume this discussion is about cold bluing that involves applying a topical treatment which colors and protects the metal. In terms of protection, bluing is quite low. It's better than nothing but exposure to sweat and wetness in general will quickly lead to red rust formation. Clear coating on top of the blue surface may be possible but even at that, you won't have the protection of something like painted steel.