beautiful deep inky blue barrel

[eddillon]

Anybody know how to achieve the beautiful inky blue that you sometimes see on old pistol barrels?  I have seen it on an N. Boutet and on some old presentation Colt percussion revolvers.  I have an Ed Rayle barreled pistol that I am building as sgift for a friend in Turkey.  That blue would be the final touch for the gun.

[Acer Saccharum]

Inky blue?

[D. Taylor Sapergia]

I'm pretty sure its done in an oven - to around 800 deg F. on a mirror polished barrel.  It is a very thin and fragile finish...probably requires a laquer covering.

[Acer Saccharum]

The above is a heat blue. I did it with two propane torches, slowly playing the flame, teasing the color up from bright steel throught he colors, straw, brown, purple to this royal blue. A little more heat, and the blue is a lighter tone.  If you go too far with the heat, you have to re-polish and start all over again.

This is not a very durable blue, but it's handsome. You can lacquer over it for some protection from sweaty hands.

[Acer Saccharum]

D.T., you type faster than I do. 

[D. Taylor Sapergia]

Therer are quite a number of barrels in Steinschloss Jagerbuschsen that are blued thus.

[Acer Saccharum]

I think the blue will last forever, as long as you don't shoot or touch the gun. Or drool on it.

I have to say that the experience of watching the color change from bright silvery steel to the royal blue is one of the most magical I've witnessed. It's heightened by the addition of gold inlay, which does not contrast with the steel....until the steel starts to turn blue.

Jerry Huddleston has done a lot of this work. He's built special ovens just for heat blue.

[eddillon]

Only problem is, I have low temp silver soldered the lugs. ;  Tom, your barrel is a work of art.  Drool and fondling it would be a problem

[Acer Saccharum]

Ed, rust blue may be your only option, or, ugh, cold blue. Rust blue is a blackish blue, not as rich as the fire blue, but by golly, it's durable.

[Dave B]

Tom, I like your results with the torches. Bouetet would be proud. Did you use the  fan tips on the torches? I have a Jaeger barrel that I will be doing one of these days and its going to be charcoal blued.  What was your final grade of abrasive on this barrel before its finish polish?

[Jim Kibler]

Your barrel is beautiful Tom.  Think that everytime I see it!  For small pieces such as pistol parts, potasium nitrate can be heated and used to soak the parts.  I've not done this so maybe those with experience can comment.  Bivins wrote about it in an article on metal finishes.  Will have to check this out.  I understand the longer hold times at temperature result in a more durable finish.

[kutter]

Yes nitre (potassium nitrate) taken up to 830/850F will give you the same look.
It is used by some and passed off as charcoal blue so that gives you an idea of the look.
The extremely high polish is what brings out the best in it's appearance.

It can take a bit of trial and error to get the exact temp right. Different types of steel will color differently.
Don't go passed the 850F mark by much, you'll get into a dull grey color.

Suspend the part(s) in the nitre,,don't let them touch the sides or bottom of the container you're melting the salts in.
I've always just done the parts in a single run. No extra coatings trying to build layers up.
Left in the stuff for 5 minutes or a bit more,,they are about a blue/black as they are going to get I think.

Let them hang & cool after taking them out. They'll have some  nitre still coating them in a hard shell.
Hot tap water will rinse that away,,but don't do this rinsing anywhere around the molten salts.

Be very careful around the stuff. No water anywhere in the area of the molten salts.
If you think a droplet of water in molten lead is a violent explosion,,this stuff is twice that and you can't get it off of yourself.

The soft soldered parts preclude the use of it in this case. But perhaps the lugs could be refitted and hard soldered into place or staked in. Hard solder, & braze will of course hold up just fine through this high temp nitre.

[Jim Kibler]

Kutter,

So the results of a potasium nitrate treatment as you described are different than the temper blue shown by Acer?  Based on your description I would expect this.  Temper blues such as shown form around 600F. 

[Acer Saccharum]

I hope that a longer time at a certain temp would give a more durable finish; but alas, I don't know the answer to that.

[JPK]

Not as pretty as Acers but here's my first test piece using char coal to blue.
Polish & cleaned then packed in lump charcoal in a steel tube and heated at 800 degrees for 3 hours then aired for three days befor oiling with light machine oil.

[Jim Kibler]

Looks nice JPK.  How did you arrive at the hold time?  Do you think shorter would work?  Is there apparent thickness to the oxide layer?  Does the bore appear to be adversly affected?

Thanks,
Jim

[Collector]

Carbonia BlueCarbonia bluing for Colt, Winchester, and all fireams.

Carbonia Blue/Charcoal Blue:

This finish is produced in a gas furnace which is exactly how it was done by the manufacturers like Colt, Winchester, Smith & Wesson, and almost all other arms makers before WW II. Carbonia blue is the Cadillac of finishes. It's glossy black in appearance which has a mirror depth to it (when the metal is polished to a high luster), and hard wearing. For it to be a true Carbonia finish, it must be processed in a gas furnace retort.

[Dr. Tim-Boone]

Look here for more:

http://www.ronsgunshop.com/finishes.html

[eddillon]

Looks like I'll have to remove the lugs if I want that inky blue 

[kutter]

Kutter,

So the results of a potasium nitrate treatment as you described are different than the temper blue shown by Acer?  Based on your description I would expect this.  Temper blues such as shown form around 600F. 

A different color, different look. Since it's done in the absence of any free oxygen in the atmosphere, the buildup of the color is different. Nitre will get you colors all up and down the spectrum same as using a torch or any other heat source. It's that protection from the atmosphere that makes the difference in the depth of the color and look and even the thickness of the coating,,though all of these are fragile.
You can get the same 'spring temper blue' down at the 650 range with either process, but the nitre will be  of a different look.

Charcoal blue, Carbonia blue (two different processes), nitre coloring,,all have that in common. No oxygen from the atmosphere is in contact with the parts.
Flame bluing/torch bluing can somewhat mimick the  look especially on smaller parts, but is not the same thing.

FWIW the 'carbonia' in carbonia bluing was the propietary oil used in the process. Mixed with the char in the rotating gas ovens from American Gas Co., they really changed the way firearms finishing was done early in the 20th century.
Some mfg'rs used other oils on small parts and accessorys to save money. Linseed was used by Winchester on pins, screws, washers, even swivels. They stopped using the ovens in about 1938 and switched to Du-Lite hot salt chemical bluing as did just about everyone else. S&W hung on to it longer than most though.

Charcoal bluing often made use of (sperm) whale oil.
 
When we started fumbling with charcoal and furnace blueing in the early 90's, we asked Mobile chem lab people for a sub for 'carbonia oil',,if they even knew what it was. They did and there was one. They supplied a modern replacement and it worked fine. It just takes a while and a lot of experimentation to get your procedures right. Just like case coloring.
IIRC, the sub was a special heavy duty gear lube of some sort. Black as tar and thick as molassis.

If there's any one thing that needs to be done to bring out the full color and depth of these finishes, it's a high polish, w/o ripples or uneven edges.

[Clowdis]

After reading several articles I'm still not sure how this is done. At first I thought the parts were colored by immersing in oil and heating but then read an article that said that it was done in a furnace with bone charcoal and a primer. Anyone else have an interpretation on carbonia bluing?

[JPK]

Jim K, The temp and hold time was suggested by others and the air time after the treatment was claimed to improve the durablity of the finish. The bore is the same as the rest and I'm of the opinion that the hold time and air time allow the finish to oxidize to a deeper coating, that's just my understanding at this point. This piece was much lighter in color befor oiling and has remained the same color after about 3 months. I'm not trying to out guess others, just use what has been developed as best I can. I intend to do this work on a pistol and see how it holds up in use.

[Dphariss]

Anybody know how to achieve the beautiful inky blue that you sometimes see on old pistol barrels?  I have seen it on an N. Boutet and on some old presentation Colt percussion revolvers.  I have an Ed Rayle barreled pistol that I am building as sgift for a friend in Turkey.  That blue would be the final touch for the gun.

Smith and Wesson used to use charcoal bluing IIRC.
It is possible to do a rust blue that has good color but requires a solution with a significant level of nitric acid to make the best blue in my experience.
But it will not be "blue" but rather blue-black or black.
You may be wanting to do heat blue. Winchester used to blue parts with Potassium Nitrate with some Manganese Dioxide (IIRC) added (this from the Madis book on the Winchester). They then coated the blued barrels with oil and baked them in an oven the burn off the oil to give a durable color.
The bright nitrate blue is not very durable unless done as Winchester did which blackens it to a greater or lesser extent depending on the viscosity of the oil.

Dan

[Acer Saccharum]

Wahkon Bay rust blue. Probably six apps, with rusting, carding and boiling operations in between. This is not the glossy, liquid looking finish you get with fire blue, but it will work with soft soldered parts, as the heat never goes beyond boiling water temp.

The carding is really important, as it keeps a crusty finish from building up. A fine stainless steel brush from Brownell's is what I used. .003 wire, very soft brush, doesn't remove the blue, only the loose rust.

[PPatch]

Acer;

Very nice boiled blue finish! That is similar to what I envision for my barrel. Could you perhaps go into more detail on how you achieved the finish? For instance; did you card AND boil between each application of the Wahkon Bay browning? How fine a grit did you go to before finishing? You can PM me if you feel I am highjacking the intent of this thread (which, I kinda feel I am, sorry).

Thank you in advance.

Dave