Color case hardening vs blueing

Discussion in 'Gunsmithing' started by Pheroze, Jun 12, 2017.

  1. Pheroze

    Pheroze AH ENABLER BRONZE SUPPORTER AH Legend

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    Does anyone know the relative merits of each technique? Is one more durable, or is it purely esthetics?

    Thanks
     

  2. ChrisG

    ChrisG BRONZE SUPPORTER AH Fanatic

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    hi Pheroze,

    Color case hardening is accomplished in one of two ways.. The traditional method, and the most durable is to heat the metal in a container with both hardwood charcoal and bone charcoal. It is heated to somewhere around 1,200 to 1,400 degrees and then quenched. The other method to accomplish a brighter set of colors but a less durable finish is to use cyanide to treat the metal. The first one you can do at home, the second, not so much. Neither are as tough as bluing in terms of durability. Also a side note, if you ever see shiny color case hardening, it has been clear coated and the coating will eventually flake. untreated color case is a flat finish. There is no way to bring a metal to those temps and keep it shiny. Turnbull restorations can do any of these for you.

    Bluing is a controlled rusting of the surface into magnetite or black oxide. This produces a very durable finish as black iron oxide is actually harder than the steel beneath it. There are a couple ways to accomplish this.

    One is called rust bluing and is what I did here. It is a process of repeatedly treating the metal with a specific acid solution, letting it rust evenly, then boiling or steaming it to turn the red rust into black oxide (tacking an extra oxygen on it). Then it is carded off with either steel wool or a carding brush and the process is repeated until the finish is the desired color (usually 6-8 times but up to 20 depending on the steel). This produces a soft luster to the steel and is the most authentic finish for a traditional rifle's metal. It is also quite durable.

    Hot or Caustic Bluing involves immersing the metal in a tank of lye and nitrate salts that has been brought up to between 275 and 295 degrees. The temperature is critical as too hot or too cold will ruin the finish. This produces a deep black which is very durable. This is the finish on almost all factory made rifles that do not contain soft solder. Soft solder will dissolve/melt in the bath so anything with solder on it, (double rifles/ shotguns, soldered on sights, etc,) cannot be caustic blued. They must be rust blued.

    The last common type of bluing is used only on small parts and is not terribly durable but produces a beautiful bluish purple that accents the guns blackened finish. It is known as Nitre Bluing and is accomplished by simply bringing steel up to a its second stage temp of oxidation (700 degrees) in the presence of oxygen. The easiest way to do this evenly is to immerse it in a bath of liquid nitrate salts that is held at that temp until it turns blue, then it is quenched. You can also accomplish this with a torch but you have to be incredibly careful as you can overheat one section very quickly. It is a popular thing to do to screws and other small parts to accent the gun.

    Hope this was somewhat informative!
     
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  3. sandman0921

    sandman0921 GOLD SUPPORTER AH Enthusiast

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    Pheroze,

    Was gonna answer this, but I think Chris G did a great job, and aptly sums up the pros and cons very well in his post.

    For those in the US, if you are in the market for a company that specializes in firearms bluing, I have had good success with Glenrock Blue in SD. They've done a couple of rifles for me. This is pretty much all they do, and they offer a variety of blued finishes, including traditional rust bluing.

    http://gunbluing.com


    I love well executed color case hardening, but Chris G is correct in that it is not as durable as bluing. However, when done well, case color hardening is beautiful, at least to me, as Doug Turnbull has demonstrated. Of course, a traditional rust bluing is beautiful as well.
     

  4. Pheroze

    Pheroze AH ENABLER BRONZE SUPPORTER AH Legend

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    Thanks for the details! That is very helpful. They are both beautiful techniques in their own right. Interesting alternatives for the right application, for sure.
     

  5. Bullthrower338

    Bullthrower338 AH ENABLER AH Legend

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    Sandman,
    Did glenrock blue move from Glenrock, WY?
    They do great work
     

  6. sandman0921

    sandman0921 GOLD SUPPORTER AH Enthusiast

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    Bullthrower,

    You are correct. I was mistaken. Thanks for the correction. I was very pleased with their work on both rifles......
     

  7. Pheroze

    Pheroze AH ENABLER BRONZE SUPPORTER AH Legend

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    I was considering these for my new 308 NM build and then my gunsmith suggested Arma-Coat in a matt finish...I am thinking a dull bubble gum pink... jk...but it looks like a good solution for a rifle that will see a lot of weather.
     

  8. sandman0921

    sandman0921 GOLD SUPPORTER AH Enthusiast

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    May I suggest some nice decals of fluffy animals as well........Those would compliment the color very nicely....:ROFLMAO:

    In all seriousness, I know Wayne Jacobson at AHR uses GunKote on his rifles unless otherwise specified. I'm not sure what Arma-Coat is, but I'm sure it's very similar. It looks good, and is very durable. Certainly if your 308 Norma is gonna be exposed to the elements, the synthetic coatings are the way to go I would think......
     
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  9. Mekaniks

    Mekaniks GOLD SUPPORTER AH Elite

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    Good thread Pheroze thanks for bringing it up. And ChrisG response is excellent!

    For what it's worth...If you are looking for a durable rifle finish you might also look at Black Nitride. It seems to be a much more durable finish than blue or Ceracote.
     

  10. Pheroze

    Pheroze AH ENABLER BRONZE SUPPORTER AH Legend

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    Thanks for the info! Another interesting alternative:). Previously, I had only thought in terms of " bluing"!
     

  11. Shootist43

    Shootist43 AH ENABLER GOLD SUPPORTER AH Legend

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    ChrisG, that was a very informative synopsis of gun metal finishes. Thanks for sharing your knowledge with us.
     

  12. Shawn.54

    Shawn.54 AH Fanatic

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    I am looking at a process that uses metal dye to give color case hardening appearance called "Steel F/X" it is not very durable but then after that I'll have clear Cerakote put on which is very durable. The Steel F/X is a simple process done with no heat and washed off with water between applications.

    I will call Steel F/X this week and discuss there product this week and report back I'm thinking of doing the action on my 404 J.
    Shawn
     

  13. ChrisG

    ChrisG BRONZE SUPPORTER AH Fanatic

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    I just looked them up. Very interesting! It seems, when applied properly, they approximate the hues and patinas of color case but without any heat and (I presume) deadly chemicals.
     

  14. Shawn.54

    Shawn.54 AH Fanatic

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    That is what got my attention no heat and he applied it with bare fingers
     

  15. CTDolan

    CTDolan AH Elite

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    One correction to @ChrisG 's marvelous response.

    Historically, case coloring is the result of case hardening, and it was/is a vital step in the process of making (a hard, wear-resistance outer "case" on the outside of a durable, ductile core). Sometimes the colors are left intact (coated with a lacquer so as to retard oxidation, which leads to fading). Other times the color is removed via polishing (leaving the hardened surface intact, the color being but superficial). This is generally referred to as a "coin finish".
     
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  16. Riksa

    Riksa AH Veteran

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    I really like the looks that color case hardening has.

    Does anyone here know if color case hardening can be done to an already engraved double rifle? Plenty of people have mentioned that the color will wear off or flake. Do you have any example photos of the result after flaking or wearing off?

    Turnbull would be nice to contact, but as I live in Europe, it's really not an option. Does anyone here know someone making color case hardening in EU?
     

  17. mark-hunter

    mark-hunter AH Enthusiast

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    Italians do color case hardening on their replicas of cap and ball old guns. Pietta, Uberty, etc. I am not sure, though, if they will do on specific personal request, but it does not hurt to ask them.
     

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