S&W Bluing Methods

[SDH]

bis45, If you are talking about the single shot, I spent an entire week hand polishing it. No way it can be commercially viable, unfortunately. Same with individual grip making, I figured those were $800 grips when I made them about 1993.
Just finished a set of extension grips for my early pre-kit gun I-frame custom, several full days of work. Now it needs polishing and bluing, part of what brought me to this thread.

 

[frankynohankypanky]

Steve;

The Metals Handbook could also be considered to lack specifics. After an introductory paragraph, it continues;

"Various types of black finish can be secured. these depend principally upon the finish of the part before the special treatment is given. Cold drawn or highly polished parts will take a glossy black finish. Parts made from ordinary stampings will have a somewhat duller finish, while work which has been sand blasted prior to applying this treatment will have a black matte-like finish.

While not an entirely rust preventative coating, this finish acts as a retardent to the formation of rust.

To apply the gun-metal or carbonia finish, the work is placed loosely in a retort with a small amount of charred bone and heated to 700-800F. After the articles are thoroughly oxidized the temperature is allowed to drop to about 650F, when a mixture of bone and 1 or 2 tablespoonfuls of carbonia oil are added. Heating is then continued for a period of several hours. When the work comes from the retort it is a dull grayish-black and by dipping in sperm oil or tumbling in oily cork a uniform black finish is secured.

If the temperatures given will temper too much, a temperature as low as 500F can be used, but this lower temperature requires a longer time at heat to color the articles and the color is not so lasting as the color produced at the higher heats.

Gun- metal or carbonia finish may be applied to articles which have first been nitrided, resulting in a pleasing finish resistant to rusting and retaining the surface hardness on the articles, since these coloring temperatures do not temper the nitrided articles.

When a rotary retort is used and when the work is of such a nature that the slow rotation of the retort would cause scratches or in any way mar the finish, special fixtures may be used to hold the work in place. These fixtures are usually necessary only when large parts are to be finished."

As I said, a lack of specifics; 1 or 2 tablespoons in how much bone? etc., but, maybe there's another clue for those who are more knowledgeable than me.

I was in your part of the world this time last year, during a five week visit to the U.S. I have single shot rifle friends in Cody so visited them and spent a few days around Big Timber, Livingston and Bozeman. I've seen illustrations of your work and did consider trying to make contact.

Frank,
SWCA 2052
____________________________________________________

 

[SDH]

Thanks much Frank! More specific than I had imagined and I'm sure of some help in understanding the process.

There are several advantages to using a charcoal blue finish with custom work, especially engraved parts as the bluing shows the engraving at its best with no surface changes associated with rust bluing. One must remove ALL of the scratches and I would consider 600 grit required for a great blue. Some form of this process was, and still is used in England for double shotgun small parts such as trigger guards, top-levers, inspection plates, etc.

The action of this custom Marlin '94 was charcoal blued and the hammer and lever case colored by Doug Turnbull. I rust blued the barrel and nitre blued the screws. (Engraving by Michael Dubber.) There is a companion New Model Number 3 Frontier Target, (with work by Hamilton Bowen) but I don't have good photos.

Really sorry I missed you on your visit to Montana, Frank. Although only a workshop with no retail location, I welcome visiters as so many craftsmen have welcomed me into their shops at all stages of my career. Quite a few folks come through the area, as you know it really is God's country, and I almost always have time... BTW, very few know of my passion for S&W revolvers! Next time, don't hesitate! And thanks again for the references.
Best,
Steve

 

[2152hq]

Great looking custom Marlin '94.
Some more info on the blueing processes.

Carbonia Blue (called 'Machine Blueing' sometimes):
Turnbulls' charcoal blue the last I knew, is a form of carbonia blue done in a rotating drum/furnace. Originally a small drum set inside a furnace taken aside from case coloring use and was then hand rotated approx 1/3 turn every 15/20 minutes or so.
The total time takes around 2 hrs.
That was back around '92 & '93.

They may have graduated to a furnace w/drum set up that is constantly rotating on it's own by now,,,I don't really know.

How much oil (Carbonia, Linseed, new synthetic, or what ever you want to use) is dependent upon the internal size of the container you're using, the size of the vent, the temp and the time. All said,,the oil must NOT deplete itself inside the container during the process. Enough must be used to always have a smoke atmosphere inside the drum and have it discharging smoke (slightly pressurized) thru the vent to keep any outside atmosphere (oxygen) from entering.
If oxygen gets inside, it will spoil the finish as it will be discolored, hazy, uneven, ect. A tightly fitted seal betw the drum/container and it's cover is an absolute. No leaking of air into the container during the process.

The oil is mixed with the bone charcoal so it is soaked into the char before it is placed inside. Any water is driven out of both just before use. Just scatter it onto the floor of the container. It will rotate and actually at times fall over the parts in a constant turning drum,,burnishing the blue.
Too much oil, dripping onto parts, will spoil the finish. Remember, the parts were cleaned of all oil, grease and fingerprints before this.

Preheating of the whole charged drum starts the process and smoke generation before the drum is sealed up and off you go. For some reason, in my experience wood charcoal does not produce the desired finish like bone charcoal will.

Charcoal Blueing:
Wood charcoal is used in the charcoal blueing process I described earlier. No need to use bone char here.
Get it to the correct temp,,either judging by practice, the old method of soft wood splints starting to smolder, or go new-age w/a hightemp themometer.
Too hot and you'll spoil the blue and scale the part. Too low and you won't get any blue. Make sure the part is completely buried in the coals (keeps the oxygen out). A gas burner underneath the pan or container is great for controlling the temp of the coals rather than a wood fire as was used originally.

Don't do this inside! Aside from the smell of the fire and smoking oil being cooked off on recoated parts,,,,charcoal even if only smoldering, gives off carbon monoxide.

With the above info & the earlier post, I've described the process and the basics I use. The only other way to achive results with it would be to spend countless hours over a charcoal pit blueing parts by this method as I have over the last 35yrs. As with most everything in olde gun metal finishes, practice and techniques developed from that practice, will get you results.

Be ready for some great and some not so great results. Then with the latter,,,sit and wonder what went wrong when you think you did everything the same.,,,and you may in fact have done so!

I don't take in much work of any kind anymore for a couple of reasons and don't offer the charcoal blueing outside of any I need to do for myself.

 

[SDH]

Thanks for your info 2152hq. Learning the process sounds a bit like learning rust bluing, about anyone can turn the parts blue, but consistancy and quality are relative to years of experience.

BTW, I saw your engraved Hepburn on another post, extremely well conceived and executed! and great lettering, an under-appreciated skill!

Another pic of the Marlin showing rust blued barrel and Mag tube, charcoal blued forend cap (Turnbull) and nitre blue mag cap and screws.(Mike Dubber engraving)

 

[davidj]

The Real Question May Be, What Kind of Steel?

I love this forum.

It is unlikely that heating to 750F would anneal heat-treated steel. For example -- 4140 (chrome moly carbon steel) is used very commonly in the manufacture of firearms for receivers, bolts, barrels, and other high-stress parts. It does not anneal completely until heated to 1600 F. Hardness treatment requires quenching from 1550 F. Tempering requires re-heating to a range of 400 F - 1200 F. See Alloy Steel 4140 - All Metals & Forge [Again, normally you consult material data sheets for the steel you are using, and those tell you things like, how hot you should heat the steel for tempering in order to achieve a given hardness result (e.g. 40 Rockwell).] You could heat the steel to 800 F and leave it there for a weae and while it might acquire more temper (assuming it had not previously been heated to 800 F) it is not going to anneal.

BTW, this begs a related question....which is, what kind of steel did (and does) S&W use in its revolvers? I think the stainless is mostly 316 (not sure) but I have never been able to find out. If you could find out what types of steel were used in a particular revolver, then you could consult the data sheeets for those steels and assure yourself that heating to 750 or 800 F was not going to materially change the hardness of the steel. I checked the previously mentioned sources (Jenks' "1857-1945" and Parsons "Early Single Actions") and couldn't find any reference to the type of steel used (although there were a couple references to steel suppliers). I also searched this forum and couldn't find anything. Anyone have any insights?

Also -- what could be used as a modern analog for Carbonia oil?

 

[davidj]

Thanks everyone for the great pictures.

 

[Onomea]

Holy Mackeral! Nothing like blundering into a thread where some guys who really know their stuff are talking!

That is gorgeous work, Steve.

Thanks to you all -- very interesting!

 

[2152hq]

You're correct,,it's just like rust blueing in that no matter how long you do it, it always seems to be able to throw you a curve even if just once in a while. Plus a printed 'how-to' can get you started, but that good old experience is the only real way to get it down. Everyone has their own little tricks, techniques, ect that gets them their best results and they rarely match the other guys way of doing this 100%. But both can turn out equally nice work. Nice details on that Marlin. I like the use of different finishes to compliment the complete project.

That Hepburn goes back to the owner soon. I have a feeling I'll be getting a barrel, butt plate and some screws to do some work on. Thank you for the compliments on the work. It's one I'll probably never see the finished rifle though. Other hands doing work on it (wood, finish, etc) and not in what I'd consider anything of a correct order!,,but it's their gun..

The Carbonia process may not fully anneal 4140, but when dealing with and refinishing older firearms, most of the time you have little or no idea what the steel is. Nor do you know what the heat treat characteristics are, what temp/time they were drawn back to, or how what you are about to do may alter what has been done by the factory as an established safety criteria for a heat treated part.

A part made from 4140 that was originally drawn back at under 800F, now subjected to 800F during the process is not going to maintain the same strength in all likelihood. Different applications call for different degrees of tempering. Without knowing what the original steel is in some cases, let alone the spec for tempering is just guessing from there on out. Annealing is the complete removal of applied hardness to the metal. Tempering is removing some of the hardness on a known scale to maintain tougness w/o brittle structure. Material data sheets and Machinists books will give the rundown on what a known steel will harden and draw back to when subjected to certain temps and times. That's helpful info but it won't tell you what a gun part is supposed to be in terms of hardness (if you do happen to know what steel it's made of). Mfg's are stingy with steel, heat treat info and methods.

It's not an area you want to guess in my opinion,,but I've been known to be conservative when it comes to stuff like this.
Hell, people get upset if they see purple/blue temper colors from an over zelous soft soldering job on a barrel or receiver and reject the gun that the steel strength has been compromised. What about putting the same part in an oven at 800F for a couple of hours, then letting it cool. I think that may, in some cases, change things.

Just got to be careful that's all when doing stuff like this and think about what you may be doing to that steel before proceding. You don't want to make a potential safety hazard and put into someones hands. Certain firearms,, mostly of a more modern pursuasion, just shouldn't be subjected to it IMHO.

I feel you should stick to parts that would have originally had or were available in these types of finishes. Obtaining a finish like these just for the sake of it on 'critical' parts, safety be damned, is foolish.

The blueing processes will just make them softer than before,, if anything. Not like case coloring where you can potentially create an overly hardened piece. If you think they never get warpage or cracked pieces,,think again. A Browning 86 out of the quench cracked totally in half is quite a sight. There's that unkn modern steel again.

 

[davidj]

The Carbonia process may not fully anneal 4140, but when dealing with and refinishing older firearms, most of the time you have little or no idea what the steel is. Nor do you know what the heat treat characteristics are, what temp/time they were drawn back to, or how what you are about to do may alter what has been done by the factory as an established safety criteria for a heat treated part.

Right, exactly.

It's not an area you want to guess in my opinion,,but I've been known to be conservative when it comes to stuff like this.

Agreed.

But do you think it'd be "safe" if you were only heating to the 500-550 F range? It seems like this level of heat is unlikely to bring about any significant changes...(?)

 

[2152hq]

500 is better obviously that 800,,
Also, though I've read that a 500/550F temp range will produce a blue finish using the Carbonia method, I was never able to make it happen at that low a temp. I'll be the first to admit my experience with the Carbonia method is far far less than the Charcoal method. But 500/550F didn't produce anything but a grey hazy cast to the metal.

Perhaps others doing the process with more time & experience have developed the necessary technique to tease the blue color out at the lower temps. It would surely be advantageous to run the parts at that temp as opposed to 800F if you could avoid it esspecially when dealing with critical parts like frames, barrels, etc.

Older descriptions of the method often mentioned varying the temp during the process and lowering it at some point to around 600F IIRC and back up again. Everyone using the process surely developed their own little techniques and tricks for getting good results. It's the same with case coloring.

So much depends on what steel you are dealing with and exactly how it is supposed to be delthandled with as far as it's hardening & tempering qualitys go.
The time @ the drawing temp means alot (soaking ), quench or slow cool down, any temp variation needed during the soak, etc.
They are not all a simple 'heat it up and quench makes it hard,,,heat it a little draws the temper'. Some demand some fairly sophisticated equiptment and procedures to get where you want to go. Vacuum furnaces, salt baths, etc are some of the things sometimes necessary to properly deal with some modern steels in heat treating.

A quick story....
I will never forget the 'one-of' shotgun proto-type,, finished, in the white but still soft. Needing hardening, the owner/mfg asked if a certain C/C/H person could harden it. "No Problem,,I'ts all just iron" was the confident answer. "It all goes in the same furnace".

Not wanting to listen to someone else with machineshop experience that offered to gather proper heat treating info on the steel type, which was provided by the mfr,,into the furnace it went.
It came out looking like a giant pretzle from the County Fair and no case color other than a bit of blue against a grey back ground. The color was actually not a problem as it was going to be polished back to a 'french grey' but the contorted parts were.
Again,,"not a problem",,,as the twisted forend iron was tightened into a bench vise. A couple of educated taps and push here and there and it'll be all back in place. The sharp snapping sound like an icicle breaking off of a roof on a cold January morning told another story. No attempt was made to straighten the action and side plates.
Moral: Know what you're dealing with before proceding....

 

[frankynohankypanky]

Steve,
I love your work. That Marlin is just gorgeous, as is the 39A you are shown holding in your Custom Rifle Gazette article. My first rifle was a 39A that my Dad bought for me in Fort Worth during a work related visit to the U.S. in 1959. I was 11. He just walked off the plane with it in his hands. Things have changed!!!!!!!.
Was on the 'phone to our mutual friend SPG yesterday. Says he must get up to Livingston to see you again.
I'll be over again in May.

Frank S.
SWCA 2052.
___________________________________________
"We can't stop growing old but we can choose to remain immature."

 

[leochicca]

S&W Blueing

Hi davidj, If you can find a copy of "Firearm Blueing and Browning" by R.H. Angier, it might answer some of your questions. It was published by The Stackpole Company of Harrisburg, Pennsylvania in 1936. Much of its contents are beyond my comprehension but you may find some useful information.
leochicca

 

[SDH]

2152hq, "Hard-fitter" was a job title at one time... (along with "polisher") the scariest thing I ever have to do is straighten warped case hardened parts, but sometimes it has to be done!!!
The top tang of this action, one lock plate and the forend iron warped. After straightening, was left with a tiny gap, wood to metal, on the iron, but that was the best I could do!!!! This 12 ga. also features case colors and charcoal blue (top lever, safety & guard) by Doug Turnbull, rust (brls) and nitre blue (triggers & screws) from my shop. I do like 'em colorful! (Stain the stocks red too!)

(the bridles and all engraving by Larry Peters)

Frank, I missed Steve last time I was in Cody at the gun show, but saw all of his cronies (and some juicy S&W's, about traded a Colt for a Smith 32-20). Be sure and look me up next May if you are in the neighborhood. I still own the Marlin 38-55 that is in my Custom Rifles book. That 39A was a dream job, but you might notice the transparency was flipped in the CRG photo, it's bass-ackwards!

And thanks to all for the encouraging words!
Best,
Steve

 

[boykinlp]

While doing some browsing, I found this thread and thought it had alot of good info in it. So BTT so others could see it or see it again.

 

[Raider]

Excellent discussion. Thanks for reviving this thread.

Charlie

 

[SDH]

I am currently at work on a website devoted to custom guns and fine gunmaking.
Am always interested in information about historic firearms metal finishes.

 

[boykinlp]

SDH
You are quite a craftsman. Very nice work.

 

[Bullet Bob]

It's threads like these that keep me coming back to this forum. Thanks to everyone who participated.

As soon as my ship comes in, I'm going to have Mr. Hughes do a Low Wall .22 for me!

 

[PJGP]

Hi davidj, If you can find a copy of "Firearm Blueing and Browning" by R.H. Angier, it might answer some of your questions. It was published by The Stackpole Company of Harrisburg, Pennsylvania in 1936. Much of its contents are beyond my comprehension but you may find some useful information.
leochicca

I agree about the contents! One confusing thing is that he constantly refers to "browning", while most of the formulae actually give a blue/black finish. Here are the pages relating to the S&W method.

Peter