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How to patina a carbon steel blade using mustard

Discussion in 'Wilderness & Survival Skills' started by Trout Tamer, Dec 6, 2006.

  1. Trout Tamer

    Trout Tamer

    Jan 20, 2004
    I figured I'd post this in a new topic so that people could get the info more readily. The idea of this post is that mustard creates a nice patina on carbon steel blades, inhibiting rust and looking... interesting, sometimes even neat :p The patina can wear off, but it's decently durable, safe to prep food with, and readily replaceable. Are you ready for the instructions? Here we go.

    Necessary materials:

    -sandpaper. Grit size needed is explained in the instructions below. I greatly prefer the sanding action of aluminum oxide paper.
    - mustard of any type. I explain the difference in mustard selection below.
    - steel wool. 0-0000 gauge, whichever you can get most readily. You'll only need a pad or two.
    -the knife that you're going to patina :p

    1) The blade must be clean and free from other coatings. If it already has a coat, the purpose of the mustard is negated. I've never tried to patina a buffed, shiny blade, but I have a feeling that it wouldn't work too well; the buffed surface would repel the mustard, greatly reducing its effectiveness.

    2) Using your hands or a small stick, such as a ruler, rub the knife blade with sandpaper to prep the steel's surface. Wayne Goddard recommends leaving the surface with a 400-grit finish before patina. Thus far, that has worked fine for me. If your knife has a higher-grit finish, such as 800 or 1,000, give it a light rub with some 600 grit wet/dry sandpaper.
    a. sand the blade in one direction, going from ricasso/handle to the tip. Sand somewhat lightly until the blade is free of surface uncleanliness. If you went in one direction, your scratch marks should be fairly uniform. That actually doesn't matter too much, though. They'll be covered by the patina.
    b. as Goddard recommends, I like to give a swirling effect to the blade before patina, by running the sandpaper in circular motions all over the blade, once I've given it the initial, uni-directional sanding. The blade looks neat and the patina has a greater visual depth to it.

    3) We're ready for the mustard! Rinse your blade with water and dry it on a clean towel. Pour yourself a quarter-sized blob of mustard on a small plate. From my experience, mustard type affects patina color. Plain, ol' yellow mustard seems to give the deepest blue-gray coloring. Brown mustard or horseradish mustard gives a lighter coloration. I prefer the deeper hues.

    4) Lay your knife on one side and, using your finger tip, lightly blot a small amount of mustard on the blade. Keep on blotting small bumps of mustard on the steel until you've covered most all the blade. Now, lightly connect the bumps with a thin smearing of mustard so the whole blade is coated. I've had best success with this technique. Wayne Goddard states that he doesn't like to let the blobs touch. Just remember - if you're not satisfied with the end product, you simply repeat the sanding and mustard applications for a new outcome.

    5) Turn the knife to its other side and cover it with small mustard blots. Coat the spine of the blade, up to the handle, with mustard blots. This isn't an exact science, so don't worry too much if it looks messy - it IS messy ;)

    6) Place the knife in a safe location and let it sit for the next 6-8 hours. Arrange the knife so that neither side of the blade is flat against any surface. Allowing the mustard to smear at this early stage will undue the interesting, mottles effect that the blots will give it. Over the course of time, the mustard will turn black - this is normal. It will also be fairly odiferous - this is also normal :eek:

    7) After the waiting time has elapsed, wash the mustard off with sink water and wipe it dry with a towel. Then, using fine steel wool (0-0000 gauge), scrub down the blade. This will knock off any weak patina. Don't worry if nothing comes off, that means the patina set well. After steel-wooling the blade, give it a quick rinse and dry to remove any steel wool filaments.

    8) Blot the blade sides and spine with mustard again. This time, make sure to blot directly over the less-patinad areas. This will help give the blade a thorough rust resistance.

    9) Let the knife sit for another 6-8 hour period. Letting it sit longer won't harm the knife, although a bit of surface rust may form at the handle/blade juncture. If this happens, lightly wipe it off with some finer grit sandpaper after you've finished the patina.

    10) Repeat the wash/steel wool cycle (step #7).

    11) Repeat the mustard blotting and drying cycle for a 3rd and probably final time.

    12) Repeat the wash/steel wool cycle for a third and probably final time.

    At this point, you are finished. I've yet to see a patina improve with a 4th patina cycle. However, if you want to give it a shot, go for it! If you're simply not happy with the outcome, you can always repeat the procedure.

    Keep in mind that this patina will come off over time. I've found that tight-fitting Kydex sheaths will eventually take the patina down. I don't find this to be a major cause for concern. The blade coating can always be touched up, or even completely redone, with more mustard.

    Have fun with the process and with learning a new way to care for your knife. And, of course, keep us informed, preferably with pics, of your efforts :thumbup:

    Trout aka Zack
    JORDAN PLASSE likes this.
  2. mete

    mete Gold Member Gold Member

    Jun 10, 2003
    Good outline !! The active ingredient in mustard is of course vinegar [ acetic acid] .Other things can be used , lemon [citric acid], ferric chloride [an etchant for circuit boards], hydrogen peroxide ,hydrochloric acid [muriatic acid] .Concentration of solution , time and temperature are the variables .Patina is the best way to treat a carbon steel blade otherwise you are always polishing it !
  3. SkunkWerX


    Jul 27, 2006
    Good thorough description. thanks for taking the time, Zack.

    There are also gun blueing products out there, Birchwood Casey is one of the bigger manufacturers. I wa going to try using gun blueing, it should give a nice dark protective oxide coating? any thoughts?
  4. RokJok


    Oct 6, 2000
    Hey Trout, thank you for the specifics on your patina regimen. The only downside I see to it is that 6-8 hour drying time. I'm not that patient. ;) :D

    There are some pix of a patina attempt I did on an Okuden Sharp Thing II (ST2) a while back at the link below. I used Miracle Whip first, then some drops of vinegar. Which is sorta the same thing, since the vinegar in the Miracle Whip is what stained the A2 steel in the first place.

    To get a patina going, there was some talk about sticking the blade into an apple or potato overnight. Some folks swore by it, others were dissapointed in their results.

    The most comprehensive and quickest patina I've achieved so far on a carbon steel knife was with the boiled vinegar routine. On A2 it made a dark charcoal colored patina coating that seemed quite resistant to further corrosion. The recipe looks like this:
    1. Get white vinegar (the cheap 69-cents/gallon kind works fine).
    2. Heat some vinegar in a pan to a boil.
    3. Cover knife blade with hot vinegar. I set the knife upright in a water glass & poured in enough boiling vinegar to cover the blade.
    4. Let sit for 10 minutes.
    5. Remove knife, rinse well with water, and dry.

    There is some patina info info in the links below. If you do a search here on BFC you'll find lots of threads on it. If you are really interested, do a Google search... ;)

    Happy coloring!! :)
  5. 2dogs


    Apr 20, 2003
    Good post! I have used BC blue or a potato with good results,
  6. Uncle Timbo

    Uncle Timbo Gold Member Gold Member

    Nov 23, 2005
    I love this forum.
  7. Coldwood


    Jun 5, 2006
    Well this is interesting. I've always preferred Hellman's Mayonaise and a blow torch.

    Seriously, Trout, I appreciate this thread. I have always preferred to let my blades take on a natural patina, sort of like the coloring on good shotgun receivers...I have not ever thought about using mustard, but I have a couple of new blades that I will try this on. Thanks ;)
  8. Trout Tamer

    Trout Tamer

    Jan 20, 2004
    Y'all are welcome :)

    Skunk, Birchwood-Casey makes a bunch of bluing. Their Perma-Blue rubbed quickly off the blade, the last time I used it. Wayne Goddard says the best bluing available is Birchwood-Casey Super Blue. The Sportsman's Warehouse has some, so I'm gonna give it a whirl.

    I had forgetten the vinegar patina method. I wonder what the blade would look like with a base of the gray, boiled-vinegar patina, followed by a round or two of yellow mustard? I think I'll give it a go and find out what happens :D :thumbup:
  9. shecky


    May 3, 2006
    The local home improvement place has Jasco metal etchant. It wasn't too expensive, about $2.50 per qt. which I bought for prepping some steel doodads for paint. I dipped a Mora Frosts 680 in it for about 10 minutes. Came out looking almost Parkerized.

    I've done the plain white vinegar before. I simply dipped a paper towel in the vinegar and wrapped it around the blade. When it dried up, I dripped a few more drops onto the paper to keep it moist. I left it overnight, and the results looked great.
  10. Codger_64

    Codger_64 Moderator Moderator

    Oct 8, 2004
    Earlier this year I bought an old fixed blade knife, circa 1970, and it was in horrible condition. The only "history" the knife showed on the blade was gunk, rust and abuse. I stripped it down, sanded it with very fine paper untill it was clean and fairly flat. But it was still to blemished to leave shiney. I gave it a "multiple treatment patina", and it turned out great. Mustard was rubbed in over a couple of days, then I washed it well (there is some oil in mustard), and dropped it blade first in a gallon dill pickel jar. After a day of this, it was washed and I sliced, diced, and rubbed it with white onion. Each step darkened and enriched the color. I finished by washing again in very hot water, then rubbed it down with hot olive oil to penetrate the surface. The finish holds up well, and looks great IMHO. It gets even better if used to slice fresh meat.

  11. Coldwood


    Jun 5, 2006
    This is amazing! I've always gathered from posts here at Bladeforums that people like to keep their blades shiny bright. Well, I have a lot to learn. Thanks, this is very informative!
  12. SkunkWerX


    Jul 27, 2006
    I have Super-Blue on my Gun shelf. Did an old SidexSide 12 ga. with it.
    came out nice. the SuperBlue is darker and deeper penetrating.

    I also annodize aluminum and have a good apprecition for the process of building up oxide layers. Once you know what is going on, you can achieve great results.

    For steels, I have heard of poeple using vinegar too , and tomato sauce.
    Anything acidic. Of course, depending on the acidity, the timeframe and finish changes.

    I like starting with very very mild acids, allowing them a long time to penetrate, then working up through more acidic solutions which seems to build up a good durable surface layer.

    Good stuff here.
  13. SkunkWerX


    Jul 27, 2006
    OH, maybe, you could achieve a "camo" type of look, or a fade from light to dark, using different acids, painted on, down the blade... hmmmmm????

    might be worth trying on a beater blade..see what happens?
  14. Gossman Knives

    Gossman Knives Edged Toolmaker Knifemaker / Craftsman / Service Provider

    Apr 9, 2004
    There's nothing finer looking then a well used knife with a nice patina on a carbon steel blade. I've used vinegar, cold blue and ferric acid. The Hudson Bay knife I'm doing has been dipped in ferric acid. Any of these methods will wear somewhat if the blade is heavily used. I feel that gives it character.
  15. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    Or you could just cut some raw meat, then leave it a while.
  16. Gossman Knives

    Gossman Knives Edged Toolmaker Knifemaker / Craftsman / Service Provider

    Apr 9, 2004
    This is quite true. I cut up a huge beef roast (raw) with my Randall model 25 a few years ago and the blade was black. I did clean it up but the enzymes in the meat and blood will discolor carbon steel.
  17. Kyp Degal

    Kyp Degal

    Sep 25, 2005
    Thanks for taking the time to put up the tutorial, Trout. Great job on it as well. I put a nice white vinegar patina on my Ranger RD7 a few weeks ago, then just yesterday patched some of the wear in the patina with an application of yellow mustard. Turned out pretty good. I think I'll try another vinegar treatment on it, too. I'll see if I can get some pics of it over the weekend.

  18. rifon2


    Oct 9, 2005
  19. tiros


    Nov 29, 2006
    Thanks for the great post Trout, I'm gonna have to try it out.

    Did you know that in the old days they used to use urine to patina metals? Apparently it left a durable long lasting browned finish. Come to think of it, I have seen some muzzle loading rifles in museums that looked pretty darn good for their age. I learned this at a local "black powder days" festival when I was a child and its always stuck in my head, they used to pee on their guns. :barf:

    I think I will stick with the mustard.
  20. GibsonFan


    Jul 7, 2006
    Umm... no. But it makes sense, given what SkunkWerx said about using weak acids over a long period of time, I guess. "Touch-ups are a whiz!" Ho ho.

    I used BC Perma Blue on a CS Rifleman's hawk last summer, and am pleasantly surprised by it. I think the fact that the hawk seems to made of very simple steel, plus the fact that I applied the BC 4 times instead of 2, worked in my favor.

    Got my Master Hunter soaking in a glass of lemon juice right now... we'll see how that goes.


    Ten minutes in lemon juice definitely had an effect... subtle and kind of nice. It has a more brown or sepia tinge to it now, instead of bluish. Previously it was only stained form cutting meat and veggies and whatnot.
    The only problem is, it's starting to really show off the less-than-ideal satin finish on the blade...

    update: Well, well, this is gettin cool... after another hour of soaking in the lemon juice, the blade is much darker. The brown has deepened to black and the blue hues came back in spades.

    I bet it did! According to their website, that's 40% phosphoric by weight. Good stuff.

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