Charcoal Bluing

[Avlrc]

Brian LaMaster

[L T Grey]

I’ve been hesitant to try charcoal bluing as I’ve read that it leaves scale in the bore. This Brian’s video has convinced me to go ahead and try it.

[A.Merrill]

  I never heard him say how long he cooked the barrel. Or did I miss it?   Al

[Kevin Houlihan]

In the comments on YT below the video, Brian said that it was about 3 hours total cook time.

[54Ball]

 Very simple method.

 Some of the methods mention a regular removal of the barrel, and a rubdown with clean cotton rags that have been loaded with powdered lime.

 I wonder if the lime wipe, darkens the blue?
That method has the barrel breeched with the bored filled with packed charcoal.

 Still another method is suspending the barrel just above the coals. The “above the coals” is not really a charcoal blue but a “heat blue” via charcoal.

[CooleyS]

Since the heat would melt solder, would soldered on barrel lugs or sights be done after the heat treatment, or does this method require lugs to be dovetailed in? I wouldn’t think soldering post heat treatment would alter the color on the barrel. Thinking of round barrels mainly…
-Steve

[rich pierce]

Since the heat would melt solder, would soldered on barrel lugs or sights be done after the heat treatment, or does this method require lugs to be dovetailed in? I wouldn’t think soldering post heat treatment would alter the color on the barrel. Thinking of round barrels mainly…
-Steve

He mentioned that braze would likely hold up but lower temp silver solders and soft solders would not hold up.

[L T Grey]

Does 12L14 barrel steel color differently when charcoal bluing than 1137 or another non leaded barrel steel?

[CooleyS]

Since the heat would melt solder, would soldered on barrel lugs or sights be done after the heat treatment, or does this method require lugs to be dovetailed in? I wouldn’t think soldering post heat treatment would alter the color on the barrel. Thinking of round barrels mainly…
-Steve

He mentioned that braze would likely hold up but lower temp silver solders and soft solders would not hold up.

Yes, I did hear that in the video, but if brazing was not used to attach sights and/or under lugs, then would the heat from soldering change the colors of the heat treatment on the barrel or cause any other problems?

[rich pierce]

Ahh I see where you’re going now. It would have to be low temp and quickly done.

[whetrock]

I'm assuming he had the rear sight in place during bluing. Did he also have those brass front sights in place, or were those installed after he pulled it out? If this was mentioned somewhere, I missed it.

[Clint]

I talked to a man at Kemton two years ago who had done a lot of charcol bluing.. My stroked brain won"t let me remember his name right now biut he is pretty well known. I have done a huge amount of metal work over the years and as we discussed the proccess it became more clear to me that the charcol roast may have originanny been a stress releif technique and the color was secondary. He said that the roasted barrels were easier to load and clean. I have a fifty cal green mountain thats ready to roast as soon the weather warms up and as long as local brush fire conditions are small. C Wright

[kutter]

No need to stuff the bore w/ charcoal or anything else when charcoal bluing.

IF you are getting heat scale in the bore , then you will also have it on the outside surfaces.
That tells you that the bbl got too hot.

Sometimes the heat scale is mis-interpreted as a Charcoal Blue.
It can be a very thin and even coating of acceptable color to the 'smith, but it is heat scale. You definitely do not want that inside the bore.
Anything over or near 900F will produce heat scale on steel. That's the point that the metal starts to glow red. You are passed the point where simple temper colors appear. Heat scale will form at that point as the part is able to contact the oxygen in the air.
Keep it under that point and you will have the temper colors. Deep blue/black is what the 850F range will produce.

The charcoal blue forms when the part is kept at a temp around 830/850F.
Deep blue temper color is what it is. The last temper color on the chart.
After that and if the heat increases to around 900F, the steel starts to incandesce/glow.
From that point and forward is when heat scale can occur if the part is allowed to be in the open atmosphere. The previously obtained deep blue temper color is taken over by a gray color to the steel.

The same color can be gotten from a Nitre bath at the same temps.
The fact that the part never is allowed to go above the 850F point makes it possible to remove the part from either method and examine it & some burnish it down as well.
The same temper color will occur inside the bore or part(s).
Keep the heat under control and it will not heat scale.

Carbona Blue is also done at the 850F range. Same temper point with the addition of the char being sifted and dropped over the parts as they revolve in the chamber.
Some say the parts receive a bit of carbon in the surface from this process as well. I don't know enough of the chemistry of it to say.
What the sifting of the char over the surfaces does do is the same thing that repeated removal and scrub down of the surface w/ lime or other products does.
It burnishes and does seem to even up the color if that starts to occur.