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Discussion Starter #1 (Edited)
There are several kinds of case hardening. In very simple terms it is adding a hardened skin to a soft low carbon steel.

Case-hardening involves packing the low-carbon iron within a substance high in carbon, then heating this pack to encourage carbon migration into the surface of the iron. This forms a thin surface layer of higher carbon steel, with the carbon content gradually decreasing deeper from the surface. The resulting product combines much of the toughness of a low-carbon steel core, with the hardness and wear resistance of the outer high-carbon steel.

Colt uses a traditional method far as I know but they do change things around a lot so who really knows? I have begun to wonder when you see the distinct change in colors on Colts' work. You can see every thing from the more obvious traditional work of Doug Turnbull to stuff that could easily be just another case hardening process ( salt bath? ) that was used.


a well used Colt from 1973





Colt has traditionally used this method:

The traditional method of applying the carbon to the surface of the iron involved packing the iron in a mixture of ground boneand charcoalor a combination of leather, hooves, salt and urine, all inside a well-sealed box. This carburizing package is then heated to a high temperature but still under the melting point of the iron and left at that temperature for a length of time. The longer the package is held at the high temperature, the deeper the carbon will diffuse into the surface.


The resulting case-hardened part may show distinct surface discoloration, if the carbon material is mixed organic matter as described above. The steel darkens significantly, and shows a mottled pattern of black, blue, and purple caused by the various compounds formed from impurities in the bone and charcoal. This oxide surface works similarly to bluing, providing a degree of corrosion resistance, as well as an attractive finish. Case colouring refers to this pattern and is commonly encountered as a decorative finish on firearms.Case-hardened steel combines extreme hardness and extreme toughness, something which is not readily matched by homogeneous alloys since hard steel alone tends to be brittle.

A used, but newer Cimarron. Uberti uses a true case hardening, salt bath, process described below. I've long seen the salt bath process described as a "chemical process".....implying it is not a case hardening which is not only misleading but untrue. In fact the salt bath gives a harder outer skin than bone and meal case does, just not the bright colors. When you look further there actually might be some advantages to the shooter and manufacturing costs to the salt bath over the bone and meal version.




Another process
that is used on the SAA guns is a "salt bath". After seeing the process being done and the end result close up on more than a dozen guns I began to wonder and do some research.

This process is clearly seen in the Uberti video at 2:20

https://www.bing.com/videos/search?q=making+a+uberti&view=detail&mid=6DE2C4F8839BFA85345C6DE2C4F8839BFA85345C&FORM=VIRE

Cyaniding ( salt bath of sodium cyanide ) is a case-hardening process that is fast and efficient; it is mainly used on low-carbon steels. The part is heated to 871-954 °C (1600-1750 °F) in a bath of sodium cyanide and then is quenched and rinsed, in water or oil, to remove any residual cyanide.
This process produces a thin, hard shell (between 0.25 - 0.75 mm, 0.01 and 0.03 inches) that is harder than the one produced by carburizing, and can be completed in 20 to 30 minutes compared to several hours so the parts have less opportunity to become distorted. (which answers a few more questions for me on "consistent production".)



Then there is Ruger's version that is now discontinued and I don't believe was ever a hardening process but only cosmetic.



(photos came from the Ruger forum without the author's permission)

I'm lookin for information on how these processes compare in actual use. Please feel free to add your thoughts and knowledge to the conversation.
 

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It's my understanding color case hardening hasn't been needed on Colt SAA at least on 2nd and 3rd gen Colt's but is done just for tradition. The Uberti's are just a step above Ruger's faux CCH. DSCN0619.JPG Colt SAA from 1966, a shelter life for the most part I guess. The Color Case still looks good, the old charcoal and bone method.
 

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Discussion Starter #3 (Edited)
>my understanding color case hardening hasn't been needed on Colt SAA at least on 2nd and 3rd gen Colt's

true

>The Uberti's are just a step above Ruger's faux CCH

Not even close when you look at the process used. Colors and cosmetics might not be what you like but the hot salt process is likely better than Turnbull's bone and meal for getting what it required from a hardening standpoint.

I get the cosmetics and why folks like bone and meal cased colors. But to my surprise bone and meal is not the only "real" case hardening techniques.


I've seen "bone and meal" case called "real case hardening" many, many times. When in fact that isn't even remotely true. It might be the oldest process and no question it can be really pretty. But that isn't the point. The real point is, it is either case hardened, or it isn't.
 

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Bone and charcoal give the overall best results, and durability. Cyanide Hardening works too, longer it stays in the bath the deeper the Hardening goes up to a point. However cyanide hardening will never produce the colors or durability of bone and charcoal. Cyanide coloring tends to wear off and fade fast. Regular case Hardening will gradually fade too, but it takes longer. Plus cyanide is downright dangerous.
 

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Discussion Starter #5
>Bone and charcoal give the overall best results, and durability.

By what standards are you making that claim?

>cyanide hardening will never produce the colors

agreed by what we have seen to date

>or durability of bone and charcoal. Cyanide coloring tends to wear off and fade fast.

again by what standard are you judging that by? I have not found that to be accuarate

> Regular case Hardening will gradually fade too, but it takes longer.

Takes longer I suspect because there are a whole lot of Colts that simple don't get used, shot, cleaned.
 

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I base my opinion on use. Sharps rifle company, the original used bone and charcoal. Several companies that make newer copies of old single shot rifles use the cyanide method and can get some decent colors but it fades. The ripple effect is caused by how they raise the parts out if the cyanide bath, and then the quenching. Cyanide Hardening is also used to heat treat gears or some use induction Hardening.
 

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Discussion Starter #9 (Edited)
Thanks guys.

Mike, I wasn't trying to be a dick just trying to ask questions. Like Craig we all have opinions. Me as well :) My interest is in the process. Salt bath is half as deep on the metal and it is harder, than bone and meal. For guns made of modern steel that don't need hardening one might wonder which process is actually better on a SAA, if you can disregard the colors. Easy to see which is cheaper. But we also have a 100+ years of additional knowledge and technology to come up with better ideas.

My guns end up with faded blue and no matter who did the color case process generally white...be it Turnbull or older Colts. I've not found the current Uberti salt process fragile at all....quite the opposite actually.

Along the lines of with better technology? The hot salt bath has less chance of warping a frame. Warped frames are the typical cause of a SAA not shooting POA/POI when the barrel threads get tweaked so do the barrels. And you no longer have a square gun. Square gun is the key to a fixed sighted hand gun shooting where it is suppose to.

With a dozen new Ubertis here and all shooting like they should and knowing from experience there no way in hell would you ever get a dozen Colts in house from a few months production that would shoot as well one might....just might... want to start asking why the Colt QC is so bad. I have to wonder if the after market jobber's bone and meal case coloring isn't one of the issues.....warping frames.
 

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I forgot to add that my experience is based on years of collecting single shot rifles such as Maynard Sharps, rolling blocks and others. And some of these were junkets that were restored but I learned early on that the Traditional method always look the best and wear better. My 1906 Bisley that survived the San Francisco earthquake is faded on the outside, but pull off the trigger guard and you can see the beautiful colors. Each smith that does color case work kinda gaurds the exact formula that they use, one for Colts is different than what they would use for a Winchesters. Some of the least expensive Smith's have the best results. I particularly do not like color case from Turnbull, but that's me. Others like him. I enclosed a picture of my Bisley . I have a Ballard loop lever that still has good color case after years of use.
 

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Yahoody don't worry I never thought that at all. We all are just trying to learn more. I'm glad the Uberti color case is holding up. A good smith can prevent warpage. Some use blocks of steel placed where a breech block goes on a single shot rifle, some use nothing. The preparation work is the same. I have had Smith's tell me not to polish my parts past 400 grit, when I asked why it has something to do with the visual effects, more polish less coloring. On some color cased items with lots of screw holes you can see the Mark's from when they quench the parts caused by steam and bubbles going through those holes . I just prefer Traditional I guess. Hell in this day and age it's hard to find a smith that can actually Blue a case hardened part without in going Purple. And we have all seen re blued guns with purple tinted parts. I think Remington rust blued a rolling block I used to own as it was really nice deep black blue and I know it was color cased.
 

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With the early Winchester rifles the color casehardening was an extra cost option, and the blued receivers were the equivalent of the casehardened receivers. Winchester even offered an extra cost color casehardening that had much more brilliant colors.
 

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Couple of things to add here. Traditional color cased hardening is accomplished by preparing parts as Yahoody described above. Parts are “packed” into a bone/charcoal blend and housed inside of a crucible. This crucible is then subjected to a prolonged “soak” in a heat treat oven/furnace at temps hovering around 1400deg F. (Important to note that most robust parts ie SA frames, properly prepared at these temps are at little risk of warping. Thin walled receivers are another story.)From there, with as little exposure to air as possible, the parts are dumped into a bath of cool, aerated water. From my research, it seems most practitioners of the art place as much importance on this “bath” as they do on the actual charcoal recipe in terms of achieving desired colors. Very cool subject to study up on. All that said, these “real case colors” fade...pretty dang quick, under regular use. Now I know different folks have different definitions of regular use. For me this would be shooting, cleaning and carrying the gun a few times a month over the course of a year. After about a year or so of this level of use, not only will the case colors have uniformly faded, but the areas receiving the most holster wear and handling will display little to no color at all. And this is my experience starting with a lacquered finish! The laquer, as unsightly as some seem to find it, does add a layer of initial protection. But it gets gone quick. Bottom line...as I’ve discovered with both my long guns and revolvers...these “pretty colors” are pretty dang fragile when subjected to real-world usage. As for those cheesy EYEtalian case colors...I’ve actually found them to be roughly equal in terms of durability. I don’t currently own any newer Ubertis/Piettas but I have a few buddies who do. They use their guns as hard as I use mine and cover just as much ground with them in a holster. As a whole, I’d say the Uberti “salt bath” colors haven’t shown any more degradation than those on my USFA’s and Colts.
 

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Hi There,

Case hardening of steel involves the use of Nitrogen as well
as Carbon. The colors produced are dependent on the grade
of steel as well as the process used. Some steels will case
harden just fine but produce little or no color using traditional
bone/leather organic compounds. One of the modern steels
used that does is 8620.

Cyanide does produce vivid colors. It can be recognized by the
lack of any areas of the treated steel showing color. The earlier
shown Sharps is a good example of this. Cyanide will produce
colors on steels that will not color by the traditional case hardening.

The process (the way the parts are handled) have as much to
do with how the colors come out as anything. Air (oxygen) that
comes into contact with the steel before it is quenched will lessen
or prevent colors from forming. That is partially why the heat
treating boxes have to be sealed during the process. Transferring
the parts from the box to the quenching bath has to be done in
such a way to limit or eliminate the exposure of oxygen.

Lastly, the quenching bath has an effect on the colors. Temperature
of the bath will have an effect of how quickly the metal changes
temperature. Also, salts can be added to the bath to affect the
speed of the quench and hence the color. Both sodium and potassium
nitrates (and nitrites) are sometimes used in the quench. And
air is sometimes bubbled through the quenching water to influence
the colors.

So there is a lot that goes into the coloring of steel when attempting
to achieve color case hardening.

Good Luck!
-Blue Chips-
Webb
 

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I've noticed over the past few years the case hardened colors on Colts SAAs are not as consistent as say 20 years ago. Makes me wonder if the people doing the processed retired, and didn't pass on how they did the process. Some SAAs from the past say 3 years have very attractive and vivid case colors and some look mottled and bland. The Last Cowboy SAAs I've seen look downright awful making me suspect they use a chemical process on them. Who knows if Colt is still actually doing the case hardening in house since moving out from under the dome. Most of the 2'nd generation SAAs I've owned all had consistently nice looking case colors though somewhat more subdued that the late 3'rd gen examples. Here's my favorite SAA made in 1966, and I love it's case colors. Interesting topic.
 

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Discussion Starter #16
Here is a thought for you that I have already mentioned but let me go further.

From my personal experience most Colt's 1900 to 1930 pretty much shoot POA/POI. All were color cased using the old bone and charcoal method as they had from 1873. That is only 50 years so not impossible that the same people or group of people at Colt or with a sub contactor were still doing the work. The more experienced teaching the less and on for 50 years.

After WWII Colt started up production of the SAA again. Worn machines, loss of a old labor force and as the 2nd gens life span ended so did much of the quality brought to the table by a very skilled work force. That all ended before the start of the 3rd Gen guns.

Along comes the 3rd gen guns. Lots of changes. And I would suspect a lot more folks involved that weren't as skilled as the 2nd Gen builders and before. 3rd Gen guns may or may not shoot. Shoot? As in POA/POI.

Skip ahead a few decades and you have USFA. Their "unfinished" Rodeos were know to shoot. I've had a bunch of them and never had one that wasn't very close to POA/POI if the front sight was vertical. While most of the Turnbull finished color case guns shoot exceptionally well, there have been a few that were dismal. I am totally convinced guns that are built square shoot straight.

Having a jobber color case your basic frame....and not being the guy who has to build the guns in the end is a problem that jumps out at me. A warped frame in the case hardening process gives you a gun that won't shoot POA/POI. Basically they don't shoot straight.

My thought process goes like this:

Colt did their own color case work and the guns were good
3rd Gen guns Colt jobbed out the frames and guns weren't so good.

USFA didn't color case the Rodeo and the majority of them really shoot well.
On occasion a case colored (by Turnbull) USFA gun didn't shoot worth a damn

Uberti uses a totally different case hardening technique with little chance of a warped frame and their guns shoot POA/POI very consistently. They also take some effort and time to stand their front sights up straight.

SAA is actually a pretty complicated gun to get up and running correctly, as they can be had. Way more so than a 1911.

thoughts?
 

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Hi There,

Yahoody, you may be employing a causal fallacy. Just because
a revolver that has a case colored frame doesn't shoot as accurately
doesn't necessarily mean it was the CC that caused it to have
accuracy problems. It is completely circumstantial. There are
too many variables involved here. Unless you have done a
scientific analysis with proper testing equipment and careful
elimination of all other possible factors can you make such a
statement.

Although it is entirely possible that frame warping during the CC process
can cause a revolver to not shoot to POA, there are other reasons too.

Good Luck!
-Blue Chips-
Webb
 
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