beautiful deep inky blue barrel

[tyro]

Colt's midnight blue  was a process with pulverized charcoal and straw...perhaps you could see if they left behind details by checking LOC.GOV...or one of the other guys' memory might be bettern' mine...

[dagner]

 their is a old time  top profesional real gunsmith in  downtown alton ill  that blues a whole bunch of differnt colors from black to colt blue seen some of his work .out of sight. price is  above normal but so is his work
dag

[FL-Flintlock]

Y'all are running different rabbit trails but there are many to choose from.  First off there's no such thing as a specific "carbonia" oil, carbonia is as Vasaline is to petrolatum.  The carbonia name is merely clever marketing by AOF, the first company to produce semi-automated industrial blacking machinery that utilized one particular method of blacking.  The process that was done at 600-700°F with the temperature and retort loading formulation adjusted according to the specific alloy being blacked.  The basic principle of generating the proper balance of CO/CO2 via the different methods are essentially the same whether using a basic charcoal process or the same with the addition of an oil bath/wetting.  Some mfg's added a post-char to the process which went by many different names such as lustering, cottoning, buffering and flaming just to name a few of the more common ones.  In the late 1920's early 30's the semi-automated blacking process was refined by adding a high-pressure steam pretreatment; late 30's or early 40's is when the gasification process came about and variations of both remain in use by some industries yet today.  Just a word of warning, different oils were used based on their particular properties at that time.  If one tries to utilize modern production oils, petroleum or synthetic, one best have a thorough working knowledge of the modern additive packages and their effects - not so much on the resultant color produced but more importantly their effects on the alloy being blacked or you're going to be in for surprises that can range from a simple "oh $#@*" to "catastrophic failure".  Just because Mobil SHC or Texaco TMGL are similar in appearance doesn't mean they are acceptable.  But, then again, what do I know compared to the salesmen at the hobby store?

[keweenaw]

Jim and others.  I've done a moderate amount of nitre bluing.  It's really no different than heat bluing. You can watch the piece come up through the colors to get what you want.  The advantages are that you don't go over temperature like you can about instantly with a torch and the entire piece is heated evenly so you get uniform color.  But as others have said, different steels will color at slightly different temperatures.  Charcoal bluing is an entirely different matter.  Charcoal bluing puts a thin layer of scale on the surface of the work and can be very durable as the scale is hard.  Unlike the heat blue it takes some time to develop the scale layer.  How glossy it is depends on the initial filing/polishing/burnishing done on the piece as well as how clean it is.  When you lose the surface on a charcoal blued piece, like the trigger guard of buttplate of traditional English work, the scale flakes off rather than wears away.

Tom

[kutter]

Y'all are running different rabbit trails but there are many to choose from.  First off there's no such thing as a specific "carbonia" oil, carbonia is as Vasaline is to petrolatum. 

The carbonia name is merely clever marketing by AOF, the first company to produce semi-automated industrial blacking machinery that utilized one particular method of blacking. 

The process that was done at 600-700°F with the temperature and retort loading formulation adjusted... But, then again, what do I know compared to the salesmen at the hobby store?

That's why I called it 'propietary' in my earlier post. Amer Gas Furnace Co put that name (Carbonia) onto the petrol product that produced the desired results with their machinery (The American Gas Furnace Bluing System) and sold it as a package to the industry.
Some stuck with the AGFCo ingredients and methods,,some went their own way and used other oil(s) and other mixes of char. Bone char.
S&W used their AMGFco ovens right up into the 60's, maybe early 70's and if I recall right they were one of the very few to actually apply 'Carbonia Blue',,AGFCo supplied the oil and char ingredients to S&W for the process.
I think Winchester did as well, though they did small parts and fittings with linseed.

Others including Colt used the furnaces,,but never bought into the AGFCo proprietry ingredient oil (Carbonia) & mix.


Yes, you can get results with other oil(s). Some you'll get terrible results. Some will be acceptable.
It took us 2 1/2 years of experimentation in every phase of the process to finally get acceptable results at DTR.
I know full well what the process is all about as well as the charcoal blue process.
Yes there was a certain oil that was used for the original process and that is not available anymore. The substitute we were advised to use worked out well and as far as I know continues to.
But,,there are several other ingredients in the bone char along with the oil that make up the charge. That and the time, temp controls are all very critical

No,,I am not a salesman in a hobby store nor have I ever been one.

[FL-Flintlock]

Kutter,
Have you had a full spectrum test work-up done on alloys treated with packaged lubricating oil(s) to compare with untreated parts from the same alloy? 

[Dphariss]

Thanks Kutter.

Dan

[T*O*F]

It took us 2 1/2 years of experimentation in every phase of the process to finally get acceptable results at DTR.

Kutter,
I may have missed your introduction along the way.  Who is DTR and what is your name?  I have a couple of S&W projects down the road that will need to be reblued when I finish with them.

You can PM or email me if you don't want to post it publically.
Thanks.

[Chuck Burrows]

DTR = Doug Turnbull Restoration http://www.turnbullmfg.com/

[T*O*F]

DTR = Doug Turnbull Restoration

Thanks Chuck.  Nuff said....their reputation is tops.  I just couldn't place the initials.

[Chuck Burrows]

you are most welcome...

[JTR]

And by the looks of the samples on their website, they, and kutter, have a very good idea of how to put various colors on gun metal!

John

[eddillon]

Never generated 3 pages of opinions and suggestions before.  Kinda neat.  Still don't know what to do but I am leaning toward the 6 applications of rust blue/brown,  I thank you all for the inputs.
Ed

[Dennis Glazener]

This is from an non-ALR member that wanted to offer this information.

Dear Mr. Glazener,
Please pardon my intrusion, I am not a member but visit your American Long Rifles website on occasion because I take interest in the great diversity and beauty of American muzzleloading arms. Although I have nothing to offer in the manner of building or shooting muzzleloading arms, I do wish to offer comment in reference to the message thread "beautiful deep inky blue barrel" as it within the realm of my experience producing specialty metal finishes. While I am not at liberty to discuss the particulars of our metal finishing processes, I would like to stress the necessity of considering changes to the mechanical properties of alloys as associated with thermal finishing operations as touched upon in the replies by “FL-Flintlock”. The composition of the finish producing materials, particularly lubrication oils including the base oil, additives and modifiers, all have the potential to greatly affect the alloy being finished. Because all aspects of thermal metal finishing processes can affect the yield, tensile and proportional strengths of an alloy directly or as a result of element uptake, hydrogen embrittlement, temper embrittlement or intergranular corrosion, thorough testing of treated alloys used in critical applications is mandatory to ensure safety of the finished product. Any thermal metal finishing procedure, especially those where the processing temperature exceeds 233C, has the potential to not only produce mechanical property changes but also induce surface micofractures compromising structural integrity.

If so desired, you have my permission to post the contents of this email and my name to the forum but please omit my contact information as our services are offered only to industrial manufacturing entities.

With kind regards,
Helmut Kutz