Cold Blueing

twhite

twhite

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Sep 10, 2022
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Looking for some solid info. I have some tooling lathe holders and the likes that I want to cold Blue. What brand works best that you have tried.

Thanks!


Cutting oil is my blood.
 
Caswell's black oxide finish or Brownell's Oxpho-Blue are both excellent (and about equal).
Most important is the process. Clean and degrease thoroughly. Then (contrary to the name of the process) - heat the piece(s). I like to boil them with something to keep them off the bottom of the pan. Let your parts boil for a few minutes so the heat can soak through. This heats and does a final degrease / clean.
Pull them out and rub on the bluing. I apply it generously and leave it on for longer than instructed...
When you're tired of waiting, wipe it off.
Card it (buff with #0000 steel wool or a good carding wheel).

Lather, rinse, repeat as many times as you like to get the darkness and/or gloss you're going for.
As a final step I toss my parts into used motor oil after the last step. This neutralizes the compound you've been using, soaks into the metal to protect it from rust, and seems to make the color a bit darker. I usually leave it for several hours.

To reiterate: the process is most important. I'd rather do it as desscribed above with Birchwood-Casey (probably the worst of the cold blues) than have someone use Caswell's blue and follow the instructions...

You might be tempted to try some test pieces, and there's nothing wrong with that, but if you're bluing a different alloy results may not be at all representative.

Good luck!

GsT
 
twhite said:
Looking for some solid info. I have some tooling lathe holders and the likes that I want to cold Blue. What brand works best that you have tried.

Thanks!


Cutting oil is my blood.
Click to expand...
Here is a photo of a tool that I cold-blued.

I cold-blued the tool's mild steel parts using Birchwood-Casey's Super Blue. For prep, I used medium emery cloth to remove mill scale and followed that with fine emery and a thorough cleaning using denatured alcohol. Then I blued the parts -- repeating the process to deepen the blue -- and followed that with an over-night soaking in motor oil.

HTH, Bill
Gray Knurler 3.jpg
 
I bought some on Amazon Birchwood Casey Super Blue. Seems to work well. Oops, see Bill already mentioned it. Mike
 
GeneT45 said:
Caswell's black oxide finish or Brownell's Oxpho-Blue are both excellent (and about equal).
Most important is the process. Clean and degrease thoroughly. Then (contrary to the name of the process) - heat the piece(s). I like to boil them with something to keep them off the bottom of the pan. Let your parts boil for a few minutes so the heat can soak through. This heats and does a final degrease / clean.
Pull them out and rub on the bluing. I apply it generously and leave it on for longer than instructed...
When you're tired of waiting, wipe it off.
Card it (buff with #0000 steel wool or a good carding wheel).

Lather, rinse, repeat as many times as you like to get the darkness and/or gloss you're going for.
As a final step I toss my parts into used motor oil after the last step. This neutralizes the compound you've been using, soaks into the metal to protect it from rust, and seems to make the color a bit darker. I usually leave it for several hours.

To reiterate: the process is most important. I'd rather do it as desscribed above with Birchwood-Casey (probably the worst of the cold blues) than have someone use Caswell's blue and follow the instructions...

You might be tempted to try some test pieces, and there's nothing wrong with that, but if you're bluing a different alloy results may not be at all representative.

Good luck!

GsT
Click to expand...

Thanks for the in-depth process. I will head over to the Gun shop next week and pick up some.


Cutting oil is my blood.
 
I use Caswell, works great. Have you searched the forum archives? Plenty of information already posted.
 
twhite said:
Looking for some solid info. I have some tooling lathe holders and the likes that I want to cold Blue. What brand works best that you have tried.

Thanks!


Cutting oil is my blood.
Click to expand...
I've had good success with Jax Iron Steel and Nickel Blackener:

Metal Blackener Solutions - JAX Chemical Company

Fast acting, water-based metal blackener solutions easily darken aluminum, pewter, brass, bronze, copper, silver, iron, steel or nickel.
jaxchemical.com jaxchemical.com

Around here, it is much more reasonably priced than the products oriented to the firearms crowd.

Craig
 
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