Darkening Stainless Steel?

[rmnc3r]

I fab'd a replacement Percuss'd hammer using steel of unknown provenance that turned out to be Stainless of some sort.

I've had some success, previously, in darkening some Stainless by etching with Muriatic Acid and cold bluing / browning (LMF, Wahkon Bay) - It would come out a medium to dark grey (almost like a French Grey). This hammer is resisting any and all attempts to darken it, however.

Any suggestions besides Caswell or Paint?
https://caswellplating.com/metal-finishing-solutions/stainless-steel-blackener.html

[Marcruger]

Depending upon the composition, some stainless will turn black.  I once saw a friend's unmentionable pistol where sweat had leeched under the wood grips.  The stainless had literally turn black, and it could not be polished off.  At least not without removing a lot of metal.  In that case, I'd guess hand salts and acids did the job.  Or salts or similar in the wood grips. 

[rich pierce]

Fire works. You can get temper colors. Next is particulate-enhanced browning. Rub stainless with the sludge that firms when home-brewing iron saturated AQF or from cleaning files with vinegar. Make a slurry of that sludge plus your browning solution. Apply generously and leave damp for days. Micro-pitting will start where the particulates sit. Keep working it but it will be tedious and not as pretty as browning mild steel.

[Not English]

Back in the '70's i worked for Dairy Equipment Co. We used to dip  stainless in a tank of hydrochloric acid. It would come out a gray color similar to "paint kote" steel. I'm wondering if something like that might take some browning solution?

[rmnc3r]

Back in the '70's i worked for Dairy Equipment Co. We used to dip  stainless in a tank of hydrochloric acid. It would come out a gray color similar to "paint kote" steel. I'm wondering if something like that might take some browning solution?

Thanks for the ideas.

I have and use  Muriatic Acid (HCI) which is a weaker form of Hydrochloric, and it has darkened some stainless I've tried it on.
This stuff must have more %age of alloys. Heating the part help some but the color just wipes off leaving a less shiny surface.

I have some Vinegaroon from file re-sharpening, so I think I'll try to get some of the sludge from the bottom of the jug and try that.

[BOB HILL]

 Birch wood Casey use to offer a product to blacken stainless. I’ve never used it.
Bob

[Not English]

rm, I'm not advocating unsafe use of chemicals, but I think the hydrochloric acid was considerably stronger. The gray was in the metal, although it could be ground out. This was pre-OSHA and they still took safety precautions as far as work and handling goes. Maybe some straight Nitric Acid might work.

[Clark Badgett]

Why not just remake the part from some regular steel? Then it will never bother you that you have stainless on your rifle.

[Dphariss]

Cerrocoat.  I have a cerrocoated stainless barrel on a brass suppository gun that is black. It comes in an array or colors. Most shops that do gunsmithing can do this.
This problem an example or why we should avoid making gun parts from unknown scrap.
Dan

[Dphariss]

Some stainless is much more corrosion resistant than others 303 and 304 are not hardenable but are very corrosion resistant, its also non-magnetic. You could hang it on the wall with a sign saying something like "$#*&!" And make one from low carbon. Where I live I can get low carbon from Pacific Steel and Recycling. Has to be someplace like this around where you live and steel is not that expensive.
by mail but the freight can be a pain.

Dan

[fahnenschmied]

Heat it till glowing a dull red.  Often this will convert stainless into rustable steel.  Might repeat it two or three times. 

[Clark Badgett]

Heat it till glowing a dull red.  Often this will convert stainless into rustable steel.  Might repeat it two or three times.

How does that get rid of the nickel and chromium in the alloy?

[fahnenschmied]

It doesn't get rid of the nickel and chromium, but the high heat of forging certainly discolors the stuff, and possibly the structure of the molecular makeup is altered by the heating cycle.  All I know is that I have forged some stainless steel and the parts that I let cool naturally began to rust much like mild steel.  The parts I quenched generally did not rust.  At the time I was trying to make replacement springs for WWII paratroop knives, and found that it is difficult to make a stainless spring.

[rmnc3r]

Heat it till glowing a dull red.  Often this will convert stainless into rustable steel.  Might repeat it two or three times.

Vielen dank, Herr Fahnenschmied

Heating to dull red a couple of times and using Mark Lee Express Blue after it cooled a bit, then spraying with water to covert the brown to blue did the trick

[BOB HILL]

An old welder once told me that the high heat caused the iron to migrate to the surface therefore it is able to surface rust he was pointing out a weld on a ss hand rail that was not wire brushed after the weld. I know high heat can turn brass pinkish from the copper coming to the surface. I guess ss can do as he said.
Bob

[JCKelly]

Fahnenschmied has it. Heat that stainless to a red heat for a while & it will form a black scale.
That scale is mostly chromium oxide Cr2O3. Since it is no longer in the steel at the surface, that steel may or may not react with your bluing stuff.
Any way heating red will blacken it.

I worked with stainless & similar alloys as a metallurgist for a few decades. Can say enuff about it to make you quite tired.

[Clark Badgett]

I worked with stainless & similar alloys as a metallurgist for a few decades. Can say enuff about it to make you quite tired.

I still have to work with it. And it seems my boss takes great pleasure in giving me the parts that are stainless and require lots of material removal. If there are 2 metals that I loathe working with it's stainless and bronze.