doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Case Coloring

Very early on, gunsmiths would immerse a wrought iron spring in molten lead, then quickly quench it in linseed oil. The spring was then placed over heat to temper it. The gunsmith gauged the amount of tempering by the color, yellow, then violet, then blue. Pale blue was used in tempering springs.

This can be seen in the video, "Gunsmith of Colonial Williamsburg" with Wallace Gusler.

Pete

Others have detailed the process of bone charcoal case hardening which imparts colors to the surface as well. Over the years, gunsmithing books have told of the various mixes of charcoal, charred leather, and such that were added to the crucible. Some say that some gunsmiths urinated in their secret charcoal mix to get different colors. I suppose anything is possible, but it wouldn't be pleasant. Actually, it seems the quench process has more to do with getting vibrant colors than the pack, but it's probably both... and the steel... and the temperature... and the time... The folks who do it well are often pretty secretive about their process.

When I was an apprentice electrician, I spent several months working in a blast furnace. The restrooms were some distance away from the cast house, and as a prank, occasionally someone would urinate in an iron runner between heats. When the furnace was tapped and the molten iron hit the urine soaked coke dust lining the runner, it would flash to steam, often with an impressive explosion. The smell would fill the cast house, and it was nasty. Very nasty! Even though the cast house had no sheeting on the sides, and the cold winter winds were blowing through, the aroma was disgusting. Superheated human piss smells far worse than any skunk. I can't imagine that anyone would intentionally heat urine with a torch to put fake case colors on a gun. But people do some strange stuff. It sure wouldn't make your wife or neighbors happy. Maybe Ed will chime in.

he a we go a gain...

Heating any shotgun receiver without controlling the temperature and heat duration is potentially dangerous and can damage guns and potentially harm shooters. If a shotgun receiver is heated to critical temperature, such as that required for the bone charcoal surface hardening process to be effective, then the structure of the surface metal has been changed and the metal should be tempered back to provide some elasticity. Otherwise, the receiver is as brittle as glass and may crack upon firing of the gun.

Incorrect tempering of receiver surface metal is the inherent flaw in the use of the high heat bone charcoal process when applied to shotgun receivers. A dangerous situation may develop as a result of incorrect tempering of the receiver surface metal after the high heat bone charcoal coloring process is completed. This is particularly true of older shotgun receivers, made prior to ww2. Factory tempering specifications were inconsistent, as receiver metallurgy formulas changed from time to time. Unfortunately, much of the original factory hardening and tempering specifications have been lost. Even the best of mechanics are only guessing when they attempt to correctly re temper a shotgun receiver after subjecting it to a high heat bone charcoal hardening process.

Quality case coloring should provide cosmetic enhancement without endangering gun integrity or shooter safety....Be careful if you are contemplating sending your prized shotgun's receiver to a high heat bone charcoal mechanic.. He is going heat it up to around 1500 degrees F... Make sure that you get it in writing, that if the receiver warps in the heating and tempering process or that if it cracks after firing, then the mechanic will assume full financial responsibility for the destruction of your gun and/or your personal injury.

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 original receiver metallurgy and heat treatment is not changed. No harm is done to the gun nor is there any potential for danger to the shooter, as a result of the re coloring process.

In summary, shotgun receivers should never be rehardened in the vain interest of restoring the cosmetic effect of case colors. Case hardening is a high heat process which alters the surface molecular structure of the receiver metal. Rehardening a receiver can warp it. Subsequent efforts to straighten the metal, either by bending or filing can only harm the fine original metal-to-metal fit and adversely alter the workings of carefully aligned internal shotgun parts. In addition, if the receiver surface metal is not correctly retempered after the hardening process, then the receiver metal may be too brittle and as a result, may crack upon firing.

Can anyone describe the cyanide-coloring process in detail to me? Apparently this process is used by some Continental gunmakers.

Deleted

Ed, yep, here we go again.......as I remember we've had some 20/30 plus pages of discussion on this subject , more than once, with input from those, like myself, who actually do quite a bit of firearm color case hardening.....

Your temperature windows are all wrong as usual, as is your doom and gloom scenario....... Only an idiot would fry parts at what you propose.......

After re-casing a large volume of guns over the years , I haven't seen one yet that I did, end up with problems.... Can't speak for others, but the process is well defined and it's been around since man began building swords.....

I helped Tony Treadwell with his CCH as he began, helped him with supplies and hands on problems, processes, do's and don'ts etc....... Tony as a novice and hobby gun smith using an electronic ceramic kiln/furnace had no problems and turned out some very nice CCH work consistently using time proven parameters and processes......

Color case hardening firearms has been with us at least 300 years or so and manufacturers still use basically the same processes and time lines, temperatures, quenches etc.... Gun Smiths who re-case color guns use the same numbers as well, as it is very well defined in the industry, with great success on a regular basis ......

I'm not going to debate all the details and try to convince you that frying a shotgun receiver with your torch is nasty and ugly, but it is, we've been over it before Ed, many times.....otherwise the factories that manufacture guns and "re-case" their own products, like Colt Firearms, would use YOUR TORCH METHOD.....LOL...

This poor old field grade gun of mine that I re-cased years ago has had at least 5 to 8 thousand rounds fired through it over the years and is still giving as new performance.....

I would be glad to put it up against any of your "torched" guns as a comparison for steel to steel fit, beauty, strength and longevity.....

Best,









OR THIS ONE, OR ANY OF THEM ...........

Doug,

Do you do color hardening for other collectors than yourself. Your work is exceptional!

Larry

well then, buy all means fire up the furnace and start cookin dem receivers...


http://wn.com/what_is_case_hardening

re: cyanide case coloring...most guys who try it are usually dead before they finish their first job...

Awe, come on Ed, looks like Doug's examples came out pretty good. Thanks for showing us your method. It seems pretty basic, but those colors came out real nice.