Gun Black?

  1. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask.

    Messages:
    9,702
    Location:
    UK
    I mused to have a bottle of what I called:
    Gun Black.

    When you used it on clean metal it would turn it black and give it a rust prove finish.

    What is the real name of the stuff, plus were can I buy some.

    DSCN1211.JPG DSCN1200.JPG DSCN1034.JPG



    want to blacken these or give them a gun metal blue finish.
     
  2. colnerov

    colnerov Member

    Messages:
    3,047
    Location:
    Nr Gatwick UK
    Hi, I think it's actually called 'gun blue'. However I've just watched a video on Youtube and he used white vinegar. -



    Colin
     
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  3. slim_boy_fat

    slim_boy_fat Forum Supporter

    Gun bluing

    EDIT: Fastest finger first......^^ :laughing:
     
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  4. ihavenoidea

    ihavenoidea Member

    Messages:
    25
    Location:
    Germany
    The Prozess is called blueing. You can find various liquids on eBay with that name.

    I personally prefer Manganesing with
    phosphoric acid and Manganese dioxide over blueing.

    Mfg,
    David
     
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  5. colnerov

    colnerov Member

    Messages:
    3,047
    Location:
    Nr Gatwick UK
    It doesn't happen often.:laughing:
     
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  6. Maker

    Maker nEw mEmBeR

    Messages:
    6,402
    Location:
    Don't ask questions
    Cold bluing is usually done with selenium dioxide.
     
  7. fixerupper

    fixerupper Member

    Messages:
    1,439
    Location:
    Crete Greece
    I alway thought it was done by heating until cherry red and then quenching in used engine oil ...am I wrong ?..
     
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  8. Wozzaaah

    Wozzaaah The wizard of woz Staff Member

    Messages:
    14,120
    Wiltshire, UK
    ^we did that in metalwork at school back in the early 80s.
    It was known as “oil blacking” back then.
     
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  9. Paul.

    Paul. Moderator Staff Member

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    5,932
    Location:
    Northampton. UK
  10. slim_boy_fat

    slim_boy_fat Forum Supporter

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  11. ronan

    ronan Member

    Messages:
    8,333
    dublin
    Bluing is actually passivated rust, if you heat red rust with boiling water its becomes black oxide, magnetite which protects the steel from further rust.
     
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  12. ronan

    ronan Member

    Messages:
    8,333
    dublin
    Thats not really bluing as such, but i have used that method to blacken things. The brake lever on the bridgeport head for instance, it was badly bent, so i reddened it up with the gas torch and straightened it, then chucked it into some manky black engine oil, turned out great.
     
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  13. stuvy

    stuvy Member

    I was always under the impression that would make the hammer weaker
     
  14. ronan

    ronan Member

    Messages:
    8,333
    dublin
    You can boil the steel parts up in caustic soda, thats supposed to make it blacken. Any of these cold blues solutions like the Birchwood casey stuff is not very durable, in my experience.
     
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  15. grim_d

    grim_d Member

    Messages:
    1,578
    Location:
    Scotland - Ayrshire
    The selenium based cold blue works fairly well if you are extremely stringent with the prep and cleaning it however does not prevent rust...it gives a better surface for oil to cling onto without being too "oily"

    It's not a terribly robust coating but the better you do the whole process the better it is.

    Real gun blueing is a completely different process.

    Saw that paskmakes way the other day.. very interesting I'll need to give it a try.

    Obviously some items are not suitable for heating too much.

    Here are my multifix toolholders which I blued after they were rusting over winter...it's holding up very well indeed. Phillips cold blue.

    IMG_20190430_132716.jpg IMG_20190430_132643.jpg
     
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  16. Yamhon New Member

    Messages:
    119
    Location:
    Yorkshire, UK
    IIRC there are two types of blueing, only one of them offers any rust protection and I don't think it offers all that much. I've considered Cerokote in the past instead, but havne't used it yet.
     
  17. Migmac

    Migmac Member

    Messages:
    2,937
    Location:
    Kintyre. Scotland
    Birchwood casey do bluing kits.
     
  18. merryman Member

    Messages:
    411
    Location:
    Lancaster, England
    True "blueing" is a heat treatment process, it was used by clockmakers and gunsmiths, and is simply the oxide film produced when you heat steel, it is used as a guide to tempering, ie, hard quenched steel can be tempered back by heating to "mild straw" colour for chisel points etc, blue is used for clock springs, but also as a decorative process on screws, balance wheels, gun parts, etc. Because you don't want to temper certain parts, a chemical "cold blueing" process was developed. There are other blacking processes which give a protective finish, parkerising being the most commonly used.
     
  19. gordon stephenson

    gordon stephenson Forum Supporter

    Messages:
    6,273
    Location:
    Skelton in Cleveland U.K.
    I have done plenty of oil blackening, to finish and protect clean metal, Certainly no need to heat anywhere near red, heat with a blow torch etc and just keep dipping into the used oil, item usually gets on fire when lifted, then dip it back in, Repeat until you get a nice satin black,
     
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  20. Tangledfeet

    Tangledfeet Forum Supporter

    Messages:
    747
    Location:
    St Andrews, Fife, Scotland
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