Nitre bluing step by step.

calebibcalebib Senior MemberPosts: 1,701 Senior Member
I was finishing up a rifle build today (which I will start another post about) and I needed to nitre blue a few parts so I thought I take a few pics and show you all the process. It's actually very easy though not without some risk.

The first step is polishing the parts. To be blued today was a steel grip cap, some action screws, bolt stop screw and the bolt stop cover. I wanted a fairly bright finish so I polished them to 600 grit. The screws got spin polished in a drill and the cover and grip cap were hand polished up to 600 then finished up on the buffer.

Sorry for the blurry pics.

Hand polishing.

Buffer polishing.

The parts then get hung from a piece of thin wire and degreased.

The nitre salts are then heated up to between 575 and 650 degrees.

The part is then suspended in the molten salts until the desired color is achieved. You can get a range of colors including the straw color found on Lugers and the like.

The part is then quenched in water. Care must be taken to ensure you don't get any water in the molten salts, that is unless you want a 600 degree mini volcano.

Dry it off and give it a coat of oil and you're done!


  • Farm Boy DeuceFarm Boy Deuce Senior Member Posts: 6,083 Senior Member
    Chemistry is fun.
    I am afraid we forget sometime that the basic and simple things brings us the most pleasure.
    Dad 5-31-13
  • Big Al1Big Al1 Senior Member Posts: 7,051 Senior Member
    As with all blue jobs, the prep work is the most important part to achieving the properly finished product. Very interesting and nice job!!
  • calebibcalebib Senior Member Posts: 1,701 Senior Member
    Exactly, two hours of polishing and five minutes to blue.
  • calebibcalebib Senior Member Posts: 1,701 Senior Member
    If you've ever taken apart an old gun and found springs finished in this type of bright blue, the pretty color is just a nice side benefit. After Heat treating a spring it will be brittle. If you nitre blue it and let it air cool, rather than quenching it, this will normalize the steel giving you a usable spring.
  • bhl2506bhl2506 Senior Member Posts: 1,847 Senior Member
    Nice work Calebib. Always look forward to you posting your work. :beer:
    Refusing to conform to the left wing mantra of political correctness by insisting on telling the truth does not make you a loud mouth.
  • tennmiketennmike Senior Member Posts: 26,106 Senior Member
    Looks good! That grip cap will really set off the rifle!

    Using the air cool to draw temper from the heat of the nitre bluing salts is good to know.
    If the U.S. Congress was put in charge of the Sahara Desert, there would be a shortage of sand in under six months.

  • calebibcalebib Senior Member Posts: 1,701 Senior Member
    Its in a thread a little further down the page.
  • JeeperJeeper Senior Member Posts: 2,952 Senior Member
    Beautiful work! :worthy:

    Wielding the Hammer of Thor first requires you to lift and carry the Hammer of Thor. - Bigslug
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