Charcoal Bluing Exercise

[Mark Elliott]

I attended a charcoal bluing of a barrel today and wrote a short blog post on my web site about it.   There are lots of photos.   

Here is the link: http://www.markelliottva.com/wordpress/2016/09/charcoal-bluing-barrel/

Unfortunately,  I forgot to get a photo of the finished barrel.   It did look nice once oiled up.   

[Daryl]

Interesting process - thanks for posting it.

[FALout]

Thanks for posting that Mark, I still have to wonder if there's a chance of warping the lock plate or barrel.

[Swampwalker]

Mark - thanks for posting the process.  Was there anything done to keep the bore of the barrel from bluing as well, or is bluing within the barrel bore considered harmless?  
Thanks!
Dave

[Mark Elliott]

There didn't appears to be any problem with warpage and the bore was not packed with charcoal.  The barrel was just cleaned and put in the the charcoal.   By the way,  only hardwood charcoal was used.   

[jerrywh]

 A similar process was used by some of the more experienced guys like Eric Kettenberg or others and there were minor Bore problems. I am not a big fan of this process and it is not established  historically. I recently did a seminar on different blueing process for barrels at the Oregon gun makers fair. As of this date there is no evidence to support the fact that it was ever done this way by the gun makers of the 18th century or before.
 There is historical evidence that establishes different other processes. I spent three months researching this subject and running actual experiments.  Let the war begin.

[Mark Elliott]

Richard was a journeyman at the Colonial Williamsburg gunshop for many years and he was basically showing us the way they blued and still blue barrels at the CW gunshop.   It is accepted practice there.   This process was developed by John Bivens, Wallace Gusler, and Gary Brumfield.    John and Gary can no longer defend the process.   Perhaps Wallace may defend the process at some point.  I know he believes he has seen evidence of the process on VA guns.

[Eric Kettenburg]

Jerry this is basically the same way I've done a whole lot of barrels and I've not had problems with warping or bore issues.  Yes the bore will blue, but it "shoots out" fairly quickly, or can very quickly be lapped out with a lead lap and some compound.  I don't keep removing the barrel and wiping it down, though, as to my mind this does seem like an invitation to warping (heat/cold air/heat/cold air etc).

While there may not be evidence to verify this method, on the other hand there is no descriptive evidence to verify any bluing method in an American context of which I'm aware; the period (18th century, not 19th) references I have seen are within a European context and seem to yield a different kind of blue, compared to what I have seen as remnants on American barrels.  Also, taking into consideration that the bluing remaining on the underside of a number of American barrels was (1) executed after filing and dovetailing in most cases and (2) seems to match perfectly with the bluing obtained via this method, I personally feel pretty comfortable with it.  I can't really see another method to yield the same results, certainly not any that is so simple, effective and quick.

[SingleMalt]

I've charcoal blued a number of barrels, never taking them out of the fire.  I leave them for about 90 minutes and take them out to hang and cool but also to allow the scale to harden.  After that, gently heat and wax.

When it comes out, it's a silver-blue, but darkens to a dark azure/indigo blue.

[FALout]

Those that blue like this, are you polishing the barrel to certain grit or just filing.  SingleMalt's pic looks like the barrel was polished up nice.
Another question, is there any harm to threads on breach plug or lock plate?

[Eric Kettenburg]

No problem with breech threads but DO NOT allow any oil in the breech threads prior to bluing.  I clean the $#@* out of it, loosely install, blue, then remove and oil it up and install to final position.

Lockplates are not finished like this; it would soften them and allow for premature wear.  Most lock components should be casehardened if soft iron/steel, or if modern steels, pseudo-hardened and mimic a casehardened finish or polished back a bit.

[SingleMalt]

I draw file with a large mill file and degrease with denatured alcohol.  Nothing more.  I don't see how it could damage the breech plug threads.  I shot the rifle pictured several times before selling it.  The shine is probably wax.

[jerrywh]

 It may have been Gary Brumfield who said he had some bore problems afterwards. I have a pile of notes on this procedure in my files. I seem to remember Eric saying he placed the barrel on a sheet of steel or iron when doing this. I have a copy of an earlier statement Eric made.  Nearly all my experience and study has been on European firearms. In the Dederot encyclopedia of trades and industries you can find photos and articles of blueing being done on barrels over a charcoal broiler. They were not done in contact with the charcoal. The charcoal was only a heat source. I have done about 25  experiments trying to get a perfect finish over the whole barrel and have never been able to achieve that when the barrel came in contact with the charcoal. There were always blotchy spots. My work is much different than almost any of you other gunmakers. You don't put a $35,000.00 barrel in a fire pit. Another method used in Europe was to insert the barrel in a huge pile of hot sand that was heated on a very large iron plate heated on a large forge. The barrel was withdrawn on occasion to check the color. it was done one end at a time. The first to do this process were the sword gilders.
  Ps- it is a scientific contradiction to achieve a blue color on steel or iron at  a temp of 1000 deg.F.   At a temp of about 700° F all color will disappear and the steel will turn a light gray.  At a temp of about 1000°  the steel will begin to oxidize and the color will remain dark gray blue. If left at the high color very long the oxide will begin to chip off. This will ruin the bore if allowed to continue.
  Burying the metal in charcoal will prevent oxidization to a certain extent. Depending on how air tight the container is. I have placed a sample in an air  tight container packed in charcoal for 2 hours at 1500 ° F. Then slowly cooled.  When removed the steel sample showed no signs of having been heated. It was just the same as when I put it in the pack. No color.

[JCKelly]

Heat bluing steel - as opposed to getting blue temper colors - means heating it with very little oxygen present. That charcoal blue is essentially done in carbon dioxide (CO2), which will mildlly oxidize hot steel. This means it can form a very thin, tight film of Fe3O4 (magnetic iron oxide). A little carbon monoxide (CO) does not hurt.

An atmosphere of only CO (tight packed in charcoal) will leave steel nice and bright, no color.

Industrial bluing of hardware screws and some B&D saw parts (the "shoe") used to be done in steam somewhere around 900F.  H2O will put a blue-black oxide on steel at this temperature.

[jerrywh]

 Of all the methods I have read about by different well known gun makers. Eric Kettenburg had the best method in my opinion. In the article I read describing his method he stated that he placed the barrel on a metal plate that was on the charcoal. According to my experiments this method would produce the most blemish free result and would allow for the continuous observation of the process. Maybe Eric will describe that method for us in detail. Gary Brumfield stated that George Suiter was the first to come up with the idea of pit bluing and that it they had only speculated that it might have been done this way.
  In Europe The barrels were heated over a large charcoal brazier that had a plate on top. The plate was probably copper to defuse the heat and even it out. I have no evidence that the plate was copper but it makes more sense than anything else.
 http://jwh-flintlocks.net/damascene-dederot-1640.jpg
http://jwh-flintlocks.net/dederot-bluing-gilding.jpg

[James Rogers]

Per "The Perfect Gun" first published in 1718, edited and translated by Daehnhardt and Neal.....

"Of giving colour to barrels..... black or bluish color in the forge....... there shall be made a brazier of charcoal that gives no smoke in the forge, and when it is well burnt, the barrel shall be placed among the embers, where it shall remain until it turn from blue to black, and then it shall be withdrawn so that the color may be everywhere without patches "  (That is for charcoal bluing )

(This looks like temper bluing)
"In the same way the blue color is given in embers of the furnace, also without there being any smoke, more care being taken with this color that it does not pass the blueness, because if there be any lack of care and it be retained too long in the heat, the color will change, and to give it the proper color there will be no other solution except to whiten the piece again."

[keweenaw]

I've blued a fair number of barrels including most of the barrels that Mark Silver has used on his earlier period rifles for the last 6 or 7 years.  The temperature I'm running them, 800 degree and very carefully controlled, isn't hot enough to warp the barrel which is supported by the charcoal in the tank anyway.  I do pack bores, it only takes a few minutes to do with fine charcoal with the muzzle plugged with a large enough piece.  Never hand problem with them.  While I always degrease the barrels, I use acetone a much better degreaser than alcohol which is really a poor degreasing agent, I'm not sure that it is really necessary.  (There is a fair amount of oil used in doing English charcoal bluing of mounts used on their guns.) Jim Wright, American Pioneer Videos, did a video with me of charcoal bluing last August which he is happy to sell.  People tell me the think it is very good. 

Tom Snyder

[sqrldog]

I can vouch for Tom's charcoal bluing, as I own two rifles with barrels that he blued. The barrels are a beautiful blue color and there is no discernable change in the bore other than color. Both rifles are super accurate and the barrels appear to be as straight as when they were finished by the maker. Tim

[D. Taylor Sapergia]

Tom, are you willing to outline your process?  I'd love to try it but have not for fear of ruining the bore.  I've gone so far as to acquire the charcoal, and build the burning tank.

[Eric Kettenburg]

Jerry I think you may be misunderstanding what I described at some point, or I may have explained it in an incoherent manner.  My barrels are indeed in direct contact with the charcoal.  I use big sheets of scrap metal to control the fire, like baffles or blankets, to keep the temperature down to what I consider an appropriate point as it's easy for a charcoal fire to get going too hot and the barrel will end up scaling.  I also have used sheets of scrap metal under the charcoal to ensure that neither the charcoal nor the barrel will come in contact with dirt or any impurities burning out of the pit.  I've tried stone and brick-lined pits too but simply using scrap sheet metal, like the trough used at williamsburg, is easier (for me) and I don't have to worry about wandering around in the dark at night chasing after one of the cats, stumbling over a dedicated pit subsequently whacking my head on a brick and lying dead in the yard until my wife figures out she's finally free.

My goal is to essentially obtain what is probably most clearly described as controlled forge scale.  This is what a good charcoal blue looks like to my eye; it has a 'forge scale' type blue/gray appearance, almost like a fine spray painted layer on the barrel, but it should absolutely not be flaking off or be "scaly" in any way.  There can be some mild blotching here or there but usually once oiled it takes on a pretty consistent appearance.

Again, I'm basing my own work off what remnants I see on American pieces of primarily the 18th century.  I have seen remnants of this on pieces into the 19th century also, though not many.

[Mark Elliott]

Eric,

Do you have any photos of your setup?

[P.Bigham]

 Just to add to the conversation.   Mike Miller demonstrated  on a Barrel I had at Martins Station how he simply uses a Charcoal fired forge to blue a barrel. He just ran or waved the barrel over the forge. Watching the colors and moving the barrel. Then allowing the barrel to hang and cool. Then we oiled it up. It turned out nice in my opinion. Not perfect as Jerry is talking about. But nice in my opinion for a Colonial Rifle without muss fuss. My 2 cents worth.

[jerrywh]

Eric, Thanks for clarifying your process.  Good info.  
As you stated before, There is some confusion because two different types of bluing are being done. One is a lower temp under 600°  and the other is a high temp. 800 of higher. I believe both processes were used in Europe . The high temp was more than likely on some Jaeger type rifles and the low temp or temper blue was used on French and English guns of royalty. I ran one odd test on a  polished steel pistol barrel. I put it in the furnace just as it was and not packed in charcoal. Ran the temp up to 800°  for 20 minutes and let cool. It came out just like black porcelain. It looked like black glass. I kept it for a year or so and then polished it off and made a pistol out of it.   0i am getting set up for niter bluing rifle barrels.

[James Rogers]

  In Europe The barrels were heated over a large charcoal brazier that had a plate on top. The plate was probably copper to defuse the heat and even it out.

The quoted 1718 passage I posted above says the barrel was placed in the charcoal embers.
I saw a video of Gusler using a steel plate on a burner to temper blue an ax head and it worked well but is there any documentation of a plate being used in the 18th century for gun barrels?

[bob in the woods]

P. Bingham ,  this is the exact way that I do temper blueing or "fire blueing".  Much different from charcoal blueing and not as durable.