Let's talk bluing

[David-NY]

Originally Posted by Paladinpainter

So can we infer that rust and caustic bluing are forming layers of translucent oxide of varying thicknesses? Further, that the thickness of the oxidized layer determines the color ?

Actually, no. Real bluing is not a layer. The thickness of the metal is the same before and after. With real bluing you are actually corroding into the metal. With heat coloring you are making a layer on the surface. The reason the heat coloring, color case hardening, cold blue, etc. don't do much to protect against corrosion is that you don't have all the pores, etc. in the surface of the metal. With a blued surface, all those pores get filled with oil and then help maintain a film of oil over the entire gun.

Originally Posted by Paladinpainter

You had an earlier question about a more wear resistant alternative to nitre bluing. The only thing that I could come up with is vapor deposition. Some of the gun makers are producing intense colors using the process. I've read that the wear resistance of titanium coatings is excellent.

That's exactly what I've heard and I've been thinking about using a titanium nitrate coating for small parts that are normally strawed.

I think I have a book at home that might have some info on the import of sodium nitrate in rust bluing . . .