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08-12-2009, 08:01 PM
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Color case hardening?
Hi all,
I own a shotgun with a case colored receiver. Okay. What I wonder is, when people refer to the case colors on S&W triggers and hammers--is that a different thing? When somebody color case-hardens a shotgun, they heat it up and hold it over bone and charcoal smoke. I doubt if somebody at the S&W factory is doing that. I think what you see there is simply a by-product of the case hardening process driving impurities to the surface.
thanks
iwanna
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08-12-2009, 08:22 PM
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There are several varieties and methods for producing color case hardening. All use heat, a source of carbon, and include variations on the quenching or cooling process.
The heat source is normally a carefully temperature-controlled oven oven using calibrated temperature measuring methods. The item is packed in a carbon crucible packed with granulated carbon material.
The carbon source can vary from animal bone charcoal to scraps of leather or other organic material.
The quenching bath is water or brine that has air or some gas (carbon dioxide) bubbling up from vent tubes in the bottom. The objective is to trap the color case changes during quenching.
The various color case hardening methods can produce spectacular rainbow hues and whorls in the metal, or simply a dark gray surface with little color variation. All impart a degree of hardening to the material, assuming it was capable of being hardened to begin with.
The old-time manufacturers like S&W, Colt, Marlin, Winchester, and Remington brought their CCH to a high level of art using available technology, while lesser "common consumer" manufacturers including some of the less-expensive modern Italian BP reproductions CCH was more for increasing the durability of the parts than for beauty.
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08-12-2009, 08:34 PM
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Yes, S&W used true color case hardening on their older forged triggers and hammers. They also recently had Doug Turnbull color case the Heritage series frames, using the traditional processes.
CCH basically involves packing the steel in organic material (bone, leather, charcoal…) heating and quenching. There are other case hardening processes, but the color case is the prettiest.
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08-12-2009, 09:34 PM
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Thanks, guys,
I can see I asked the right people. Very informative.
iwanna
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08-15-2009, 10:02 AM
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08-15-2009, 10:34 AM
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The colors are only a few microns thick, the hardness can be anything from nothing at all to a few .000"
It is possible to case color with out the hardening and some of the work done today is done that way. Some on purpose, some not.
The color portion of the color case hardening will abrade off quite easily on some of the work done , less so on others it seems. I worked for one purveyor a ways back that when it came time to reassemble, any problems w/ single triggers, ejectors etc. ment dissassembly/reassembly and the new colors would begin wearing already from the edges of the parts from handling. Colors,, but little or no hardening then.
Original Winchester, Marlin, LC Smith C/C parts were covered with a thin coat of nothing more than (orange) shellac to protect it. Parker didn't put anything on theirs.
I usually coat with thinned out stock finish. It brightens the colors while not looking like a coating and not filling any engraving or markings up.
The notion that direct, prolonged exposure to the sun will fade the colors has been talked about and some will agree and others not. Both sides site reasons for their arguments. I personally just don't like leaving a gun sitting in that enviornment anyway but a storefront window type of setup can do much good to the rest of the finish, be it wood or metal.
Wax protects for display I would think but for handling I'd want something a bit more substantial on the colors if they were to stick around in all their glory. A laquer or similar coating especially on a handgun can be easily redone without much problem.
It's not the most durable of finishes and was not intended originally to be a finish. It is the after effects of a process to harden low carbon steel or iron. The colors are a beautiful plus.
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08-15-2009, 11:09 AM
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On the new "classics" and "Heritage series" and any other case hardened frame done by Doug Turnbull, he places a clear coating of some some kind of violin shellac over it to make it shine like it was newly oiled and protect it.
This clear coat is fairly tough, but there some cleaners that will take it off, most notably aerosol canned products such as Gun Scrubber, brake cleaner or similar products.
I've been told to stay away even from Hoppes, but I do use it but try to keep it off the frame, and have never had a problem.
If in doubt, just use hot soap and water like you would on a black powder pistol.
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