doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com cyanide case hardening of shotgun parts

The ways of many lathe beds were listed as being Flame Hardened. These were normally made of cast iron & used the carbon in the cast iron for hardening. This was often done by a flame traveling down the ways, followed by a stream of quenching water.

I do not recall having ever seen a reference to a gun frame being so hardened. What is "Frowned" upon here is the process of using the tip of an acetylene torch to Spot Temper Color a frame. Instead of imparting hardness this actually draws the existing hardness & in an irregular fashion to boot & is very rightly frowned upon.

Cyanide hardening is done by submerging the part in molten Cyanide which is above the critical temperature of the steel being treated. Carbon is absorbed into the surface of the steel just as in pack hardening, though generally not as deep. The part is then quenched which imparts the hard case. Cyanide hardening generally has more of a "Striped" appearance than "Color Case Hardening" done by the pack method & "In My Opinion" is not near as attractive.

Cyanide hardening is quicker & less expensive than pack hardening & was used on a lot of lower priced guns, such as single barrels & hardware store doubles etc. It was not used by most of the makers of higher quality guns until cost cutting methods came into effect in their later years when they were for the most part just trying to stay in business.

There is a method of coloring gun parts, including frames, which for want of a better term I will call "Faux Case Coloring". This process was described by Ithaca back when the were importing the Perazzi. The Perazzi was made of a heat treated alloy steel & not suitable for Case Hardening. As described by Ithaca the part was heated to around 200�F or just a bit below the boiling point of water. A Cold Blue solution was then squiggled on with a Q-tip to the desired pattern. With a bit of practise one can do a rather good looking job similar to Cyanide colors. I would not of course recommend it on anything other than an inexpensive gun. I once did a Stevens 94 for a friend this way which had belonged to his father but had been neglected prior to his obtaining it. He just wanted to pretty it back up & hang it on the wall. He was extremely pleased with the way it turned out.

Due to the low temp this method does nothing to detract from the original hardness of the part. Hot bluing is done at near 300�F & even in rust bluing, either slow or express, the part is subjected to water at a full boil.

Sorry Dtm but ed has an agenda, and we've endured it since about 2006. He of late has been having trouble recalling our discussions so this might help

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=128436&page=1
Heating any shotgun receiver without controlling the temperature and heat duration is very dangerous and can damage guns and potentially harm shooters. in additional, if the receiver is heated to very high temperature, such as that required for the bone charcoal process to be effective, then the structure of the metal has been changed and should be tempered back to provide some elasticity. otherwise, the receiver is as brittle as glass and may crack or shatter upon firing of the gun. in my opinion, a low, controlled heat process, combined with specific chemicals is the safest way to recolor a shotgun receiver. so long as the heat is kept low and controlled the metallurgy is not changed and no harm is done to the gun nor is there any potential for danger to the shooter, due to incorrect heat treating, which is the inherent flaw in the use of the high heat bone charcoal process when applied to shotgun receivers.
this is exactly the potential disaster that can result in the use of the high heat, bone charcoal process to recolor a shotgun receiver. the gun becomes a potential bomb, without proper tempering of the metal after the coloring process is completed. the high heat bone charcoal process may work fine for some winchester rifle receivers, but it should never, never be used on a shotgun receiver.
i utilize the services of Ed Lander, for most of my repair and enhancement needs. Old Ed has over 60 years of experience in the gunsmithing trade and does fine work at fair prices. He has recolored literally hundreds if not thousands of shotguns receivers using his low controlled heat, chemical process. my criticism of those who case color shotgun receivers via the high heat bone charcoal method is well known, particularly by those who practice that black art as a business.
i do not know much more about old ed's case coloring process. he has developed his techniques over many years of trial and error. he even has different chemical formulas that simulate different factory colors for different guns, depending on when they were made. i believe he may use a potters kiln to precisely control heat. what i do know, is that his top priorities in all of his work are shooter safety and customer satisfaction.


He will now play the victim, simply seeking the truth, while cowardly hiding behind internet anonymity.
I can be contacted through the website listed below

dtm: in order to clarify, the above post appears to be an amalgamated, cut and paste, version of narratives that i have posted on this forum many times, over many years... the post above, accurately reflects some of my opinions and others not so...there is no agenda beyond expressing my opinions based on my own observations and that of others with far more knowledge than i...fact is, due to costs and potential risks involved; since 2010, i have not commissioned the recoloring of shotgun receivers, via any methodology...

and the fact that the above off topic post was even presented here, in its cut and paste form, makes one ponder who has the agenda...

Ed Good & dtm.....one and the same????? Hmmmmm.

le: now dats cool...maybe you could start an ot thread, suggesting which members here have more than one id...boy could i come up with a few...

LeFusil, I can assure you that I am no one but myself. I do not know Ed Good nor anyone else on this forum.

As for recoloring parts, whichever method is used, the coloration is but a single part of the process. Anyone that knows anything about heating and hardening steels, knows that they must be tempered post hardening or else you do indeed end up with a very hard yet very brittle part.

Dave Myrick

I think 2-piper summed it up well. I suspect, Dtm, you are referring to actual heat treating and not coloring for appearance. I think torching to simulate case colors is frowned upon because it�s not a flattering gun finish appearance, but it may also spot anneal in unknown variations.

An important consideration could be that gun parts may not necessarily need a very high surface hardness. Case coloring for appearance may be the practical goal without getting into the worry of distortion for various reasons. If a part was truly flame hardened by the book, that property may be lost if some degree of heat is used to create colors that�re desired. Only thoughts is all.

Yes I was speaking to the process. As I said any coloration would be secondary to the actual hardening of the steel itself and properly flame hardened and quenched parts would not have the colors of pack hardening.

Dave Myrick

dave: you seem to be a ray of calm and sunshine, re the stormy, cloudy subject of metal treatment...ed

+1 for 2-p. Hardening steel ranges from simple to verrrry complex and difficult; depending on the alloy and what result is needed. historically, gun parts have been made from low carbon steels that will not heat harden. They were plenty strong mechanically. However, they were subject to rapid wear. Fortunately, case hardening was reasonably well understood.

DDA