Charcoal Bluing Exercise

[Dale Campbell]

  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.

Well, your wife took my blood pressure the other day. She was a sweetie. I recommend you not stumble over stuff in the dark. 

[keweenaw]

Taylor et al.,  When I pack the bore I use a fine rice size charcoal like you can buy for color hardening or much cheaper like orchid growers use.  Just use a funnel and pour it full then plug with a larger piece.  I do my bluing in a sheet iron tank set above a pair of 40" pipe burners.  The tank has a lid that will fit fairly close.  The burners will run the temp in the tank up to 600 at which point I light the charcoal.  I control the heat with the lid.  If the temp is less than 800 I slide the lid open a bit, if it starts to go above 800 just slide that area of the lid almost closed. Use a lead thermometer. I find it pretty easy to maintain the temp within +/- 10 degrees of the 800 target.  I keep at 800 for 2 hours.  You need very good charcoal.  I make my own.  Some of the lump charcoal you can buy isn't charred enough and will smoke in the tank, that will be negatively influence the results.  Orient the barrel in the tank so that the top side is up.  I use a loop on the front end and one on the tang and every 15 minutes slide the piece around a bit.  When the barrel is done I take it out and hang it until I can swab some gun oil on it while still quite hot. 
Complete demo in the video  http://americanpioneervideo.com/

Tom

[P.Bigham]

 Question,  just trying to understand. If You use charcoal as a heat source and the barrel turns blue what is the difference between Temper blue, Fire blue or Charcoal blue?

[bob in the woods]

As you heat the iron / steel the  various colours will show with the rising temp.  The trick is to get an even heat so you get an even colour. That is what I know as a temper or fire blue.  The charcoal blue [ I've only ever seen one barrel with it ]  seems to me more of an oxide ....very durable  ..at least more so than a temper blue.

[James Rogers]

Question,  just trying to understand. If You use charcoal as a heat source and the barrel turns blue what is the difference between Temper blue, Fire blue or Charcoal blue?

Historically, the difference is in temperature. Lower got the bright blue and the charcoal blue at a higher temp got the blue/black

[Eric Kettenburg]

I am not a metallurgical expert but I do believe the point of a charcoal blue is to build an oxide coating as noted above.  First, it is definitely derivative of a higher temperature than the lower-temp 'bright blue.'  I do not know the exact temperature but it is definitely at the so-called "black red" heat, i.e if you were to yank the barrel out of the fire in a completely dark room, you would get the barest impression of the barrel being on the cusp of beginning to glow in a dark manner.  The point burying the barrel in the charcoal - in my opinion - is to provide a heat source but at the same time to ensure that the majority of the oxygen is consumed (by the burning charcoal) so that the amount of oxygen reaching the barrel will permit a coating to develop but will at the same time be restrained enough to ensure that it will not scale off.  That's how it seems to me.  I guess the bottom line is that there is no way anyone would mistake a lower-temp 'temper blue' for a charcoal blue.  The two are completely different things.

[Eric Kettenburg]

BTW Dale, yeah she is sweet!  Don't know how she stands me. 

[keweenaw]

Charcoal bluing as I do it on barrels is very different from temper bluing.  It amounts to a blue-black scale on the barrel that is very durable and not inclined to rust.  English charcoal bluing of mounts on guns is done slightly differently on a highly polished surface and comes out looking like deep black chrome.  I recently saw a Griffin and Tow fusil from the 1760's that still had most of the charcoal bluing on the sideplate and my Westley Richards double from 1870 still has most of the blue on the trigger guard.  If you look at more worn English charcoal bluing it almost looks like it is flaking off the surface, definitely not temper blue.  The point of any of these charcoal bluing techniques is to tie up the iron on the surface so that it doesn't rust easily as well as to make it dark.  One can get a fairly bright blue by charcoal bluing in the way I do barrels by polishing highly but I think it would be hard to get that to look even on an entire barrel as even draw filed or low polished barrels come out with a bit of mottling and areas that look a touch smoky. 

Tom Snyder

[Dale Campbell]

BTW Dale, yeah she is sweet!  Don't know how she stands me. 

And for the rest of you, she told me he's been working on amplifiers!   How he hooks up an amplifier to a rifle, wasn't explained. Nor why you would need one on a rifle.

[Black Jaque Janaviac]

I did a couple barrels following Kettenburg's descriptions back in 2000-2001.  One of those is on my workhorse deer rifle which has seen A LOT of shooting, hunting, weather & wear. 

The blue has worn in places right where I commonly hold it - right behind the front sight.  But that is about exactly what I would expect from a modern factory blue over the course of 15 years of frequent use.

The rust-resistance of the blue has really shown itself once the bluing wore thin in spots and the gun was exposed to the elements.  The bare spots rusted, the blue did not.

I will defer to folks like Kettenburg on matters of historical accuracy of charcoal bluing - but I can attest to the durability and practicality of the finish.  It really is a good way to finish a barrel.