Gun Blue Experience

[rhmc24]

BLUING METHOD I used couple times I've never seen mentioned --- I have a container of lampblack I got from Brownells over 40 years ago to color epoxy, (labeled Epoxy Black Pigment net wt. 4 oz.) about a pint for 3 bucks. I put a few polished screws on a piece of sheet copper bridging the open jaws of my vise, covered them well with lampblack & burned the lampblack away. Cooled & clean the screws were beautiful. Again later same result. Next time I didn't have enuf so I just used the torch, still using the Black in tiny amounts for epoxy, gun grips, etc. Recent years I found their price was up for a fractional amount -- OK to color epoxy it only takes a speck you pick up on a small screwdriver. Been intending to order a batch of lampblack now about $5 for 4 oz on ebay & experiment further with the 'lampblack immersion burn off procedure' but old age has force me to give it #377 of items I'll never do. I think the burning lampblack, pure carbon, has its effect & it covering the screws kept oxygen away. ----->

 

[DWalt]

Interesting idea. I wonder if powdered graphite would do the same thing? I have a gallon jug of that.

Anyone who lives in cotton growing country can get powdered graphite very cheaply. It is sold in farm supply stores as a lubricant for cotton seeds. It is mixed with the seeds to make them flow through the planting machinery smoothly. I think I paid about $15 for a gallon of it, maybe a 50 lifetimes supply for anyone who is not a cotton farmer.

 

[2152hq]

You are 'charcoal bluing' on a very small scale.

The lampblack (carbon) covering the parts and then burned is the same as the parts buried in in a glowing charcoal ember bed.
The latter was the bluing method used before the Carbonia/Machine bluing method came on the scene in the gun industry just before WW1.
All those Colt SAA, C&B, early autos made before about 1912/13 were all charcoal blued parts. The first couple years of 1911production as well.
Small things like screws and pins got Nitre blued in quantity as they were just easier to do that way.

The charcoal/carbon burns at the 800F+ needed to produce the deep blue. The burning charcoal gives off CO to keep atmosphere off the parts so they don't get scaled and discolored.
I'm told by people much smarter than I that tiny amts of carbon are infused (is that the right word?) into the surface of the steel during the process and that adds to the deep coloring effect.

Done on a larger scale, there are variations of techniques involved including actually pulling the parts from the coals for a moment and burnishing them down w/ a list of different things, to coating the parts with thin coating of oil during the process. Everyone had their own methods just like case color hardening.

Springfield Arsenal used a small parts bluing method similar to this for a time.
They coated the part with a thin layer of oil (whale oil perhaps?), then dusted the parts with either lampblack or even (hard)wood ashes.
Then the parts went into the furnace at,,830F. It produced the same type of blue.
Same idea, keep the atmosphere out, heat to produce the deep blue color.
Carbon burning at just the right temp all by itself to produce that color and at the same time giving the carbon to enhance it in the steel.

 

[gonerydin]

Interesting idea. I wonder if powdered graphite would do the same thing? I have a gallon jug of that.

Anyone who lives in cotton growing country can get powdered graphite very cheaply. It is sold in farm supply stores as a lubricant for cotton seeds. It is mixed with the seeds to make them flow through the planting machinery smoothly. I think I paid about $15 for a gallon of it, maybe a 50 lifetimes supply for anyone who is not a cotton farmer.

We use it for corn & soy beans too.


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[diyj98]

Interesting. I'd like to see someone try some larger pieces and report back.

 

[Bill Raby]

Charcoal blue was pretty common on American longrifle barrels made before the Revolutionary War.