This is what I have done to get that finish:

Basically you want KnO3, NaOH and distilled water. I will have to check my book, but it is 1 part KnO3, 2 pats NaOH and ~7 parts water BY VOLUME. Bring to a slow boil ~295°F in a NON ALUMINUM PAN.

Make sure part is clean and dry before going into the solution. Let soak in solution till part reaches desired color (~10-45 minutes). Depends on temperature and alloy of steel of the base metal. Then submerge in hot distilled water. Remove, oil and let cool. If it's not black enough degrease, clean, and start over.

Aaron & George, I have not tried this yet, but here is a link to a Caswell product that I think is what you are looking for.

http://www.caswellplating.com/everything-for-firearms/gun-metal-bluing/black-oxide-kit-1-25-gal.html

Works cold apparently, no heating required.

Thank you both.

The caswell product that Joshua provided the link for, thank you Joshua, works pretty well. It is not quite as durable as Georges method, in my opinion. You can leave the blade or part in it as long as needed, I usually go five to ten minutes. Then you rinse, pat dry, and coat the blade with the oil provided. This sits overnight and you are ready to go the next day. Works well on damascus.

Brion

George-

Do you know what the treatment does to the actual thickness of the steel? Does it build up a layer on the outside? The reason I ask is for folders. I'm going to try some and have considered trying to blacken the blades on some. The area around the pivot and lock face (in the case of a liner lock) would possibly need to be kept from the process? Or is it something that wouldn't effect pivoting and the lock up?

Aaron, I hope I'm not derailing your thread too much with these other questions...

Jeremy

George, please translate the symbols for those of us, like me, that failed chemistry 🙂

Thanks!

Bob

|quoted:

George, please translate the symbols for those of us, like me, that failed chemistry 🙂

Thanks!

Bob

Bob,

I asked the modern day version of the Oracle of Delphi (aka the Great Google)

NaOH = Sodium Hydroxide

KnO3 = Potassium Nitrate

BTW Thanks Brion for providing some feedback on that Caswell product. I was planning on buying some and trying it out, but I'm am always hesitant to throw $60 plus shipping at some unknown product.

What did you use it on and what were the problems?

🙂

Joshua, the main thing I have used it on is damascus. The main problem was impatience on my part. You should leave it with the sealant on overnight after soaking in the oxide. I did not and it was not set completely. I will have to do more testing on non damascus pieces. It works well for darkening damascus then a very light rub on the highs make a great contrast. I know Rodrigo Sfreddo uses the 295 temp method for his damascus. So far so good.

Brion

Do you guys see this as a much better alternative to cold bluing for making parts black?

I too am quite a ways away from hot bluing. I've been looking for a way to get steel parts black. Like dark black, not gray.

My problems with cold blue is that it never ends up being an even finish and it always rubs off..........always. Like right away, not eventually over time. I have tried everything. I've followed the directions on the bottle to the letter. I've tried heating the parts. I've called the shop techs at Birchwood Casey and talked to them for secrets or tips. They told me to follow the directions on the bottle. I've been super anal about surface cleaning and prep. I've tried super high polishes first and less polished more satin finishes. I've tried mild steel, high carbon steel and hardened steel, both plain and etched first. I've left parts submerged in wd-40 for days and I've sprayed them with wd-40 and hung them on a wire overnight. None of this worked. I always get a splotchy finish that rubs off instantly.

Basically I've tried everything and I can't get a nice even deep black finish that lasts with any cold blues. I'm wondering if this Caswell black oxide would be better?

John, you and I are both in exactly the same place at the same time with the same problem. This is what I am hoping to use it for. It appears from Brion's experience, this is worth a shot.

Yeah, I think I'm gonna give it a shot too. Maybe we can compare notes and findings and post up some pics.