Cold Bluing 4140

Discussion in 'Engraving & Refinishing' started by chachimacho, Jun 22, 2013.

  1. chachimacho

    chachimacho New Member

    64
    0
    0
    I fit a 10-8 sight on my M&P recently and I'm having trouble bluing the exposed metal on the front edge of the dovetail. 10-8 said to try Brownells cold blue, but I picked up some Birchwood Casey since it was available locally. Didn't work at all. I'd hate to have to send it somewhere to get it redone with the black salt bath nitrocarburizing finish. Any ideas?

    image-1689763462.jpg
     
  2. hiwall

    hiwall Well-Known Member

    4,282
    53
    48
    It is steel, right? If it is steel and degreased that cold blue will work.
     

  3. chachimacho

    chachimacho New Member

    64
    0
    0
    Yup. 4140 stock. I just did a slant pro for a 1911 today and it took the bluing like a champ.
     
  4. longunner

    longunner New Member

    1,176
    0
    0
    I know, I know, this Is an old thread but I need some help! I have an M53 Mosin Nagant that I'm trying to refinish and I bought the birchwood Casey bluing kit as well and the metal seems to not take the bluing as well as I would like. I degreased then I degreased some more then I degreased some more, before and after the blue/rust remover. I made sure to wear gloves as well so the oil from my fingers wouldn't touch the metal. I did a few coats, but it's just not coming out dark at all :confused:
     
  5. BillDeShivs

    BillDeShivs Member

    852
    4
    18
    Cold blue is not designed for rebluing an entire gun-regardless of what the package says. It is for touch-up.
    It's not even really "bluing" in the truest sense of the word.
     
  6. mountainman13

    mountainman13 New Member

    11,488
    0
    0
    Getting a good even dark coat is difficult to do. It will take a lot of time and effort but it can be done.
    Use a heat gun or hair dryer to warm the metal before application. Do a relatively small area at a time until you have one coat done. Blend with fine steel wool, oil and Let set over night. Degreese and repeat.
    It is unlikely you will end up with a great finish but it can be done.
     
  7. BillDeShivs

    BillDeShivs Member

    852
    4
    18
    Even if you get an even, dark coat it will wear off easily and it offers no protection from rust.
    Painting your gun is a much better option.
     
  8. mountainman13

    mountainman13 New Member

    11,488
    0
    0
    agreed. A couple thin coats of duracoat is much easier and effective.
    There are also better blueing options but duracoat is usually the best DIY option.
     
  9. longunner

    longunner New Member

    1,176
    0
    0
    I was thinking about doing duracoat or even cerakote. Is there ups or downs between the two?
     
  10. mountainman13

    mountainman13 New Member

    11,488
    0
    0
    I've never worked with cerakote. The only real issue with duracoat is the dry time. You really Gotta baby the gun for a couple weeks while it fully hardens.
     
  11. dwmiller

    dwmiller Well-Known Member Supporter

    3,613
    387
    83
    Some type of hot box for 12-24 hrs really shortens the cure time on duarcoat. Mine is a foam box, a couple 100 Watt bulbs and a small computer fan. Build the box out of foam board and duct tape. Get the stuff with a foil face on the inside. Mine will hold 200 degree with 1 bulb running, 250 with both. Easy bake oven for gun parts ;)

    PS mine is large enough for 2 rifle actions at one time plus small parts. Pull the tape and break it down when you don't need it. I started this because I do multi layer camo jobs and the mask can screw up an uncured first layer. Don't ask, I learned the hard way....
     
    Last edited: Aug 27, 2013