Gunsmith Blueing / Hot Bluing of Firearms

A. From the Chemical Formulary of 1941

Blue-Black Finish on Steel

Gun Metal finish on Brass

Black nickel plating bath

From Metal Finishing, 1943, J.G. Poor, Black nickel plating

Metal finishing is an art and a science, requires specialized techniques, and is now governed not only by common sense (The layer of prejudices built up before the age of eighteen-A. Einstein), but by statutes designed to conserve public and worker safety. All applicable natural, environmental and safety laws must be obeyed. It is much more effective to find out what these laws are before attempting a job, than to reflect on how easy it would have been to determine them in the aftermath of a workplace accident.

A. Steve,

As a part time gunsmith, I can tell you that most people have NO IDEA of how to reblue guns. Most blue jobs require special heated tanks, burners, special salts, and a lot of hard work. Surface preparation of the metal is a key factor because the bluing will enhance any flaws in the metal. Polishing of the metal becomes a prerequisite to a bluing job. Cleaning of the metal with solvents and a thorough degreasing to remove oils and animal fats in the polishing compounds also becomes a key issue.

Most home enthusiasts have neither the time or knowledge to duplicate a professional bluing job. If you must attempt it, contact Brownells [ Brownells home page (affil link) ] for their catalog. These people supply the firearms industry and shooting enthusiasts with parts, tools and bluing equipment and chemicals. They have some pretty good 1 step bluing kits using chemicals called Oxynate 7 ⇦this on Brownells affil link] , Dicropan IM ⇦this on Brownells affil link] , Oxpho-Blue ⇦this on Brownells or eBay or Amazon [affil links] and if you want to attempt a full Hot blue, NitreBlue ⇦this on Brownells affil links] .

Be aware of the fact that some of the older side by sides and over unders have only silver solder holding the ribs and barrels together and if you overheat the heated tanks, you could come back to 4 separate pieces instead of a fine old shotgun.

Opt for a cold blue and a lot of elbow grease. It's a lot safer. Leave the hot blue for the pros. You could probably have the job done professionally for about $125 to $175. Probably less than what it would cost you to get the chemicals and equipment together!

A. I have been practicing the trade of gunsmithing since 1963.

Unless you have some money and time to spare, have your firearms refinished by a pro. This process takes several years of experience to do right. If you want a detail explanation, I'll be glad to help. Always remember that safety is paramount.

A. After reading the comment from Maurice, I also used to have a formula for hot bluing. It was sodium hydroxide (caustic soda) and ammonium sulphate, I think. It could have been potassium nitrate. I too, cannot find my notes. I did find the four page "how to", but not the salts needed. This was from a gunsmithing class back in the 60's. The instructor was a graduate from Lassen college gunsmithing school. Anyone know of it. My notes indicate a heating of 275 °F.

CJ

A. Maurice, CJ: If you can find a copy of the Metal Finishing Guidebook from 2000 or earlier, it will have these formulas (the newer editions of the guidebook only talk about how to operate proprietary blackening baths, revealing nothing about home brew).

But the above two posts partially explain what makes hot bluing dangerous. The flash point of water is 212 °F yet these baths operate at 275 - 290 because the solution is so "salty" with caustic soda. Water evaporates very fast at these temps and the evaporation loss must be made good almost constantly. But if a slug of plain water finds itself in a pocket of 275+ solution it can instantly flash to steam literally exploding this 275 degree concentrated caustic onto everyone. Many have been seriously burned and some killed; please be careful and wear full protective gear.

A. You can get this from a druggist to make hot bluing:

spirits of niter 3 drams, tincture of iron 3 drams, sulfur 1 dram, vitriol 2 drams, corrosive sublimate 1 dram, nitric acid 1/2 dram, copperas 1 dram, and distilled water 12 ounces.

However I haven't tried it yet but I hear it works good, but I don't know what temp. to run it at.

Bill, have you actually asked your druggist for chemicals like these? 50 years ago most druggists probably could and would sell this to you, but I've lived many different places in the last 35 years and haven't run into a druggist who would sell chemicals to the public. Maybe I've been living in the big city too much.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

You may have been able to get this from a druggist when I was a boy, except, what with the American Civil War going on, all this stuff was in short supply.

I doubt that one in one hundred of today's druggists would even be able to give you the chemical formula of these ingredients without having to look it up, but nitric and sulfuric acid (vitriol) are things you won't get from a druggist. They are supposed to help people with their health, not help them to the emergency room.

  
Tom Pullizzi
Falls Township, Pennsylvania

"Firearm Blueing & Browning"
by R. H. Angier

on AbeBooks

or eBay or

Amazon

(affil links)

Oxynate No. 7



(affil links)

A. Dear Sirs:

In answer to Stephen M:

I been bluing for many years, with many products and methods , using very different formulas, but at this moment for me the better is Oxynate 7 ⇦this on Brownells affil link] from Brownells .

Polish the part very well, like an artisan, be patient, and left the part at least 45 minutes in the tank, and please let me know the result, ah, don't forget to read Gunsmith Kinks ⇦[this on on Amazonaffil links] #1

good luck:

A. I have a 1952 edition of General Metals [on on Amazonaffil links] by John L. Feirer that has a section on applying a finish to steels. I have not tried any of these (don't know where to get the supplies) and I do not know how well they will work. However for a Black finish: 1 ounce sulfur ⇦this on eBay or Amazon [affil links] in 3 ounces turpentine ⇦this on eBay or Amazon [affil links] . Heat solution in a pan of water.; For a Blue color: 2 ounces antimony chloride, 1 ounce gallic acid, and 2 ounces iron chloride in 5 ounces water. ; For a brown color: 1 ounce copper sulphate and 1 ounce sweet spirits in 15 ounces distilled water.

I would appreciate any comments about these formulas.

You get no argument from me, Mr. Burttschell -- I think you are 100 percent right, not only with respect to gun finishing, but all metal finishing. Suppliers started with the century old formulas, then spent decades improving them. And they recover that investment through selling the formulation at a markup.

If people don't wish to pay the markup, or they would rather play with their own formulations, or use what they can find published 50 years ago, that's okay. But they can't realistically expect to find the results of decades of expensive proprietary research for free on the internet.

Still ... many of our readers are from non-Western countries where these Western suppliers are not available to them and they must make their processes from raw commodity chemicals.

I agree with the gentlemen regarding refinishing formulas. I have tried many of them over the years and with the exception of molten salts for straw coloring the new methods are much safer and produce superior results. No matter what product you use the metal preparation phase is the most important. I attended a course years ago and learned that Smith & Wesson feels it take 15 years for someone to become a master polisher. That's doing it every work day, all day!

A. Hello, Jill --

You'll readily find suppliers in our Directory of Equipment or Directory of Chemicals.

The problem isn't in trying to find someone who is interested in selling chemicals and supplies! The problem is in establishing your operation in a way that doesn't terrify them about their potential liability if they do sell you this stuff.

Show them the industrial facility where you'll put the equipment, the protective gear that you will be wearing while doing the bluing, the shelves full of books about the topic, and your 'vanity wall' with certificates from Hazmat training sessions -- and they will be desperate to sell to you. But if ask them to ship it to your home, or you convey the idea that you lack chemistry experience and training, and they'll do whatever they can to avoid selling to you.