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Patina on carbone blade: how do you do it ?

Discussion in 'Cooking Knife Reviews' started by goku_knife, Jan 10, 2010.

  1. Jan 10, 2010 #1
    goku_knife

    goku_knife

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    Hello everybody.

    I'm about to receive a carbone steel chef knife, and I would like to know why and how you create artificial patina on your own blades.
    Every advice will be welcome, pictures aswell of course :)

    thanks in advance,
    GK
     
  3. Jan 10, 2010 #2
    phatch

    phatch Moderator Staff Member

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    The patina is controlled (somewhat) layer of rust.

    It helps protect the blade from other corrosion and some like the looks as it's more even and a little less care in the long run.

    However, a patina can lead to discoloring of food as you cut it, leaving dark smears on something like cheese.

    Methods, some will sitck the knife blade first in a glass of vinegar so they can watch the blade darken. On a long kitchen blade, that's not so easy. So you would wrap it in paper towels saturated with vinegar. You want a tight even wrap with no gaps or the patina will be gappy. Check it every 15 minutes or so to see how it's going.

    I like the potato method too. Stick the blade in the center of a large potato. For a large kitchen knife, you'll need a number of big potatoes, with the ends trimmed so you get a good even fit and coverage of the blade. Harder to see what's happening though. This is slower than the vinegar method.

    Some steel take quite a bit more time. On a 1080 blade of mine, it happens quickly. On an A2 blade it took hours. On a friends D2 blade, it happened cutting a strawberry. Of course, surface finish enters into the time question too The A2 blade has a high polish.
     
  4. Jan 10, 2010 #3
    pensacola tiger

    pensacola tiger

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    I just let my carbon steel knives form a natural patina over time, rather than trying to force a patina. I tried forcing a patina once by coating the blade with mustard, but did not like the result and wound up using Scotch-brite, Barkeeper's Friend and lots of elbow grease to remove it. Your tastes may be different.

    You can help the formation of patina by cutting foods like onions, apples, lemons and tomatoes.

    BTW, the term is forced patina, not artificial patina.
     
  5. Jan 10, 2010 #4
    goku_knife

    goku_knife

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    Hi, and thanks for the answers.

    this is actually exactly what I'd like to avoid ! Does natural patina keeps you away from this kind of trouble, or is it inherent to carbon steel nature to somehow not be neutral to the food you cut ?

    That's another question I have: when you don't like the result of a patina, or your blade got rusted somehow, can you ever get your knife in its original state ? How ?

    By the way, is there any diference in the result between the several ways to force a patina ( potatoe, lemon juice, viangar etc ...) ? Any pictures to illustrate ?

    Thanks in advance,
    GK
     
  6. Jan 10, 2010 #5
    phatch

    phatch Moderator Staff Member

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  7. Jan 10, 2010 #6
    pensacola tiger

    pensacola tiger

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    As I said in my previous post, a forced patina can be removed by polishing the blade. I used a worn Scotch-brite pad with Barkeeper's Friend (a mildly abrasive cleanser) to remove a forced patina I didn't care for.

    My next step, after removing the forced patina, was to develop a 'natural' patina by cutting onions, apples and tomatoes, and then lightly scrubbing the blade with baking soda as recommended by BDL in your other thread. Over time, a pleasing (to me) gray/silver patina has developed.

    Once a patina has developed, the steel's reactivity to foods is diminished to the point where the knife no longer leaves black marks on food.
     
  8. Jan 10, 2010 #7
    phatch

    phatch Moderator Staff Member

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    Toothpaste and a damp paper towel is a good fine abrasive for removing patina. Flitz is a metal polish and will do a somewhat better job, though you'll have to visit a store that sells gun maintenance stuff to find it. That might be distasteful to some.
     
  9. Jan 10, 2010 #8
    boar_d_laze

    boar_d_laze

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    Nowadays, flitz is a little more widely available than world o' guns.

    Automobile metal polishes -- especially mag wheel and aluminum billet polishes work as well.

    I don't know if the OP can even get Bar Keeper's Friend, because he's in an undisclosed European location. But it's tricky as a patina remover. It contains an acid which will start a patina on its own, if it's not neutralized (by baking soda, for instance), COMPLETELY cleaned after using, and/or the knife is oiled after cleanign with BKF.

    BKF, without any of the counter measures, is actually a pretty good way to get a patina going.

    BDL
     
  11. Jan 11, 2010 #9
    goku_knife

    goku_knife

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    Hi all.

    I think I 'll follow PT on the way to let a natural patina develop on the blade. Oignons and tomatoes being widely used in my kitchen, I think the knife will receive it's acidic daily dose. I'll keep the baking soda at hand, and see how things turn .

    thank you for those tips.
    Regards,
    GK