I have had good luck rust blueing carbon steel.

Since most stainless gun parts are 400 grade

stainless and contain about 0.5% carbon

can they be rust blued?

Not one comment?

There are a few ways to blacken stainless. The only way I know of personally, is 180 parts Sulfuric acid. 200 parts distilled water, 50 parts potassium dichromate, heat to 210F and insert metal until it darkens as much as you want to darken it and remove it. There are several kits out there that use their own proprietary chemicals.

Here's another recipe that doesn't use heat.

https://www.hunker.com/1341526...-steel-dark-or-black

I would find some 400 grade stainless bar stock pieces or something to experiment with first.

I’ve always heard that conventional bluing methods don’t work on stainless steel, but perhaps the specific alloy makes a difference.

Brownells sells bluing chemicals and they will answer technical questions like that about their products. I’d send them an email with the question.

The process of darkening Stainless Steel is an experiment at best , with any bluing product, that is commonly bought over the counter.
Too many variables , for someone who is not trained or experienced in metalurgy.
Best to look at some of the "Paint -like coatings" .

No, you cannot rust blue stainless steel.
As said there are ways to blacken it but the black stainless S&W I looked at was wearing pretty fast and looked worse than worn blue CM.

You CAN have stainless nitrided or Ionbonded for a hard dark surface.

Thank you all for your answers.

George

I carried a P226 for 15 years that has a stainless slide. It was a dark blue just like the frame. Dunno what sig puts on them but whatever it is, it’s some good stuff. In and out of a holster at least once a day, rain, heat, constant wiping down...

I've had excellent results with Caswell's Stainless Steel Blackener Gel Kit


Caswell02 by kpkina, on Flickr


Bbl rollmark by kpkina, on Flickr