Different types of bluing

49 harley

Didn't want to hi-jack the 1903 colt thread, but I may be mistaken I thought cyanide was used to get the "Colt Blue". Was it another mfg that used this in their concoction, any more info? I do remember my boss in mfg talking about this, and how it took them awhile to figure out why and how many people were dying from being over-exposed to the fumes.

rufe-snow

Are you sure the cyanide was used in the bluing processes? I was always under the impression, it was used in the color case hardening of receivers and parts.

49 harley

https://thefiringline.com/forums/showthread.php?t=298662 Google shows quite a varied search result. I'm just going on my near 40 years in the business. Was always under the impression and just conferred with a fellow still active (unlike me inactive gunsmith) who also graduated from PGS, cyanide was widely used in bluing.

11b6r

Some bluing did involve cyanide, as did color case hardening. As far as the story about unknown toxicity, the poison effects of cyanide have been known for centuries. Good story, tho.

The early Colts were reported to use a form of Niter bluing, where parts were suspended in a very hot dry mix of bluing chemicals, resulting in a DEEP black color.

https://en.wikipedia.org/wiki/Bluing_(steel)

MG1890

Cyanide is used in hardening, as part of an aqueous solution for quenching steel. This tends to leave a dull gray finish.

Never part of any of the bluing processes as far as I know.

Hawk Carse

Neither Howe, Chapel, nor Dunlap show a bluing formula with cyanide.
The Baker bluing solution contains bichloride of mercury, with which you should be about as careful as with cyanide.

Everybody gets excited over bone charcoal case hardening, but "cyanide mottling" was a very common case hardening method in mass production.

charliemeyer007

I thought that sodium cyanide would be color case and potassium cyanide gave the dull gray case hardened look.

https://en.wikipedia.org/wiki/Case-hardening

Hawk Carse

Some old methods of cyanide hardening, including a "beautiful mottled effect" are at
http://chestofbooks.com/crafts/machinery/Receipts/Case-Hardening.html#.VbBuQ_1RE5s

SP45

See if you can find a copy of "Angiers Book on Blueing and Browning". Very early and list all kinds of early formulas. he problem is that a lot of the components are toxic and no longer available.