Color Case Hardening Methods

Discussion in 'Engraving & Refinishing' started by NCSmithing, Dec 1, 2016.

  1. NCSmithing

    NCSmithing New Member

    I have recently started Color Case Hardening , and I have found through much research, that there is not a whole lot of information about CCH online. The best info I have found online was on a Marlin Forum & an article on the Double Gun Journal. Through Trial and Error , I have been able to obtain pretty decent results , but not as good as I'd like. If you have any experience CCH, or if you have any tips you would like to share , it would be much appreciated .

    I'm going to explain how I have been Color Case Hardening , and if anyone has any questions, or recommendations feel free to comment . First I get the Receiver/Parts to a pretty decent finish, I don't usually exceed 400 grit sandpaper. I then clean the parts very well , by soaking in Denatured Alcohol , or Acetone. I wear gloves when handling the parts after cleaning . I have been wrapping wire around the Parts/Receiver here lately , but I have a better method I'm going to try next time. I do this because, It seems when the Charcoal is in contact with your workpiece a little bit longer when quenched , you get more color; when the Charcoal is immediately washed away , it often doesn't get much color . I have been using a 2:1 bone/wood Charcoal mixture . I have been making all my Charcoal at home . I usually heat at 1300-1400 for about 2 hours , then remove the crucible and quench in ice cold water . I aerate the water heavily , and cut it off right before quenching.

    I'm fairly new to this , so any tips , or info would be great. I am noticing that most the things I CCH , have bright colors as soon as I remove from the Quench, but soon get a little dark after applying some oil rig. I have heard of people applying a coat of clear Lacquer, but I have not done this. I would just like to achieve brighter colors...I am getting good colors , just not too bright . I heard that it isn't necessary going beyond 400 grit sandpaper , but I'm going to try going to a high Polish, and see if it makes a difference. I will post some pictures later of some of the things I have done. I have also heard that tempering at 350 for about 30 minutes, after it's finished , will enhance colors...haven't tried that , but I'm open to ideas.
  2. NCSmithing

    NCSmithing New Member

    ImageUploadedByFirearms Talk1480607686.599888.jpg ImageUploadedByFirearms Talk1480607712.422195.jpg ImageUploadedByFirearms Talk1480607747.024882.jpg ImageUploadedByFirearms Talk1480607817.147406.jpg

    These are a few parts I have pictures of ...noting spectacular though ImageUploadedByFirearms Talk1480607958.444644.jpg

  3. c3shooter

    c3shooter Administrator Staff Member

    VERY nice work, sir! The variables, of course, will be the metallurgy of the steel, the mix of charcoals, temp and time.

    I have seen recommendations to drop temp from 1350 to 1100 after 2 hours, soak at 1100 for 30-45 minutes before quenching, and using ice before the quench to get water down to about 50 degrees.

    I have done a few small parts pretty much to see if I could, and had fair results- yours are looking really good. How are you suspending parts in the quench?

    Have also heard of including a small bit of paper inside the retort on top of the charcoal to help burn off any oxygen inside the retort.

    Have seen some of the Blue Halo false color results- was not really impressed- could maybe see that for restoration of small things on a gun that is simply not worth the time and labor to do a REAL color case hardening- but what I saw did not impress me a lot.
  4. towboater

    towboater Well-Known Member

  5. NCSmithing

    NCSmithing New Member

    Yeah I mean the results I'm getting now are okay , but I'm not impressed yet ...I think this will be something that I will specialize in one day as a GunSmith, once I get a good consistent technique down. I have also heard about switching to 1100 for the last hour or so; I've heard that this enhances colors , but doesn't give you a really thick 'Case'. I care about both the color , and the actual protective finish , but I'm more concerned about getting good Colors right now. I have been dumping a couple buckets of ice in the quench , to get it "COLD" but I haven't been aiming at a certain temperature. You asked how am I suspending parts in the quench ? I am a little confused by this ...I have just been dumping the contents of the Crucible in the Quench Tank ...I have a mesh Screen about 3/4 of the way down to catch the parts from hitting the bottom. I have been using a piece of paper at the top of crucible to use all extra oxygen ...I don't think it is too critical, but I do it anyways. I'm not familiar with the 'Blue Halo' faux CCH. I'm not too crazy about any of the 'Fake' methods...never tried any of them and don't plan to!

    I am going to College for GunSmithing right now, I have one more Semester left to get my Associates Degree...I'm still fairly young , so my knowledge and experience is limited. I haven't had my hands in the GunSmithing Field very long atall...I started this Course , a little over a year ago, as soon as I graduated from High School. I've only been CCH'ing for a little over a month, but I'm very interested in it.

    Thanks for the comments.
  6. 70cuda383

    70cuda383 Member

    Have you had any classes on materials engineering? Studying phase diagrams and TTTs for the materials you're working with. Namely steel. Understanding grain structure, crystal size, etc as you heat and cool or quench to get your iron into different phases like martensite, course or fine pearlite, etc.

    Might put you a step above the 'average' gunsmith who's just heating and quenching for coloring without understanding what it's actually doing to the metallurgy of the steel
  7. Rex in OTZ

    Rex in OTZ Well-Known Member

    I did have to take local tech school machineing course, one the other required courses was Metallurgy.
    Metallurgy is a domain of materials science and engineering that studies the physical and chemical behaviour of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys, of which is handy when cutting gears and cams.
    One can pick up a used book for fraction the cost of a new text.
    The three main methods used are: gas nitriding, salt bath nitriding, and plasma nitriding.
    Typical applications include gears, crankshafts, camshafts, cam followers, valve parts, extruder screws, die-casting tools, forging dies, extrusion dies, firearm components, injectors and plastic-mold tools.

    A machinist hand book is very handy to.

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    Last edited: Mar 28, 2017
  8. Rustyjack

    Rustyjack New Member

    Last edited: Mar 4, 2018