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Let's All Laugh At The New Guy And His "rainbow" Heat Treat

Discussion in 'Heat Treating' started by Big Bear, May 24, 2016.

  1. Big Bear

    Big Bear New Member

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    So being a guy who has made a bunch of different things I approached this knifemaking thing with, perhaps, a dash too much confidence. Surely, I thought, my knives will be beautiful and functional and great from the get go. I always seem to forget how humbling it is to learn a new skill.

    So have a look and a chuckle at my unicorn poop colored blades. I can't decide whether to scrap em, normalize and re-quench or just slap some wood on em and see how they fare.

    [​IMG]
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    For those who are interested its O1 that I brought up to critical heat in a charcoal forge. Being afraid to burn em they only soaked at temp for a couple minutes (not long enough I'm sure). Other than some obvious decarb they looked OK after the quench in canola. After 2hrs at 450 there was a bit of blue on the bevel of the smaller knife and a nice straw on the bigger one. After the second 2hr cycle they came out like you see em.

    Next time I'll use a black pipe muffle to try to minimize the scale.

    I'll also have to grab some 1084 to play with until I can source all the parts for the propane forge I'm building (what I'd do for a Home Depot less than 4 hrs away).

    Anyway, I would be grateful if any of you had any tips or ideas for how to proceed.

    Cheers!
     
    poppa bear likes this.
  2. John Noon

    John Noon Well-Known Member

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    Never got colours like that when I did 01, actually looks nice. Mind you I temper at 400 so not hot enough for pretty colours.
     
  3. Big Bear

    Big Bear New Member

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    I'm thinking I'll have to start my next temper around 400 too. Funny thing - my fears about the blue indicating that the steel will be too soft might be unfounded. The thing is still so hard my files won't bite it at all. I'm getting nowhere trying to file the bevel to final shape.
     
  4. John Noon

    John Noon Well-Known Member

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  5. John Noon

    John Noon Well-Known Member

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    Steel needs to be very clean and smooth, any contamination or very rough surfaces can create false color indications
     
  6. Big Bear

    Big Bear New Member

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    Hmm, great info on this page. Thanks for the link, John!
     
  7. dancom

    dancom Dust Maker Best Shop Tool

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    A few years back I had some CPM154 that went all rainbow on me. Unfortunately, it's surface only oxidization and rubbed off pretty easily.
    [​IMG]
     
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  8. Grizz Axxemann

    Grizz Axxemann Active Member

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    It'll buff out ;)
     
  9. Brad

    Brad Active Member

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    Surface oxidation can be deceptive. Try some cutting tests to see how it holds up.
     
  10. poppa bear

    poppa bear Member

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    I think they look awesome
     
  11. robin sorenson

    robin sorenson New Member

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    Bit that I have done many... I temper at 400 in a bbq and all of my knives look similar after tempering. I would say my unicorns are a little more evenly coloured is all. I didn’t know any better or ask anyone. I slapped handles on them and sharpened them up so far so good??
     
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