Knife Patina How To Do

A knife patina is a process of controlled oxidation and chemical produced weathering. The main purpose of a forced patina is to protect the metal from rusting by doing a controlled oxidation via chemicals. This oxidation layer or “Patina” layer protects the knife from rust.   There are many ways to force a patina on metal. My favorite for knives is to use vinegar. All you have to do is soak a paper towel in vinegar and then wrap it around the bare metal knife and let it sit for an hour or 2. The patina will last for about a couple months of normal use then you can apply it again. The beauty of it is the patina doesn’t last forever but is very easy to do and redo. The protection provided by the patina is very good and rust never forms.

When to do a patina? Anytime you want to! For me I like Carbon knives. most carbon knives come coated with powder coating or other protective coating. It does not take long with normal use for this coating to get beat up, wore off, and looking like crap. Once this happens I strip the knife with zip strip or other chemical paint stripper. then I do a patina on the bare metal knife. Another great thing about a vinegar patina is if you don’t like it or what to change it all you have to do is scrub it off with some light steel wool and you are ready to do it again. Or just do it right over top of the old one.

As I said, I prefer to use vinegar for a patina. I like the way vinegar doesnt etch to deep and is easy to replace. Any acidic food can make a patina. Mustard, Ketchup, Lemon, steak juices, etc. All of them will work. But of the ones I have experimented with vinegar is my favorite. Mustard is also good but etches deep fast.

My favorite way to do a patina is to add a little design to it. I take a piece of string and soak it in vinegar. Then wrap the string around the knife in a pattern i want. Then cover the string wrapped knife with a paper towel soaked in vinegar and let it sit for 2-3 hours.

If you don’t want the lines just wrap the knife if a paper towel soaked in vinegar and it will have a nice textured look.

If you want just pure, dark grey patina you can heat up a vinegar bath and put the knife in it. just put a pot on the stove, add enough vinegar to cover the knife and then slowly heat it up and let it get a hot bath for a while until the color is to your liking.

Here are a couple of pictures of different patina and stripped options I have done all to the same knife over the course of the last 4 years I have carried the knife. This knife is on me every single day everywhere I go. It gets used every single day. It has been thru hell and back and will make the trip several more times. Did I mention I love carbon knives, especially my Izula?

Here is how i first half stripped it by putting a piece of tape around the handle where i didn’t want the zip strip to remove paint. Then I put a vinegar patina on the blade with string and wrapped in vinegar soaked paper towel. The bigger knife in the picture is my Esee #4 and its patina is just vinegar soaked paper towel, no string.

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This is the same Izula as above but all paint stripped off and them sanded and polished on my bench grinder/polish wheel. This look is nice but it was too slippery to hold onto comfortably.

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This is the same Izula after a full patina with vinegar soaked string wrap and then wrapped in paper towel soaked in vinegar. This is how I have been carrying the knife for the last few months. I like this way the best. I actually think when I need to replace this Izula (if ever) I will immediately strip it completely and do this same patina on it. I like it that much!

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A patina not only adds protection to a knife if adds a little unique style to it. Its durable, semi long-lasting, and easy to redo. I have been putting a patina on knives for many years and thought I would share this simple process.

14 thoughts on “Knife Patina How To Do

  1. Jason,

    I wonder if that same concept would work that we use on “boiling traps” with logwood crystals or Sumac blossoms… eats rust off traps and leaves then dead dark black…walnut hulls used to do it too…messy though.

    I got to try this… few wonderful old carbon folders and sheath knives that are stained some… be nice to have them uniform in color… SWEET!

    • Logwood dye, dead oak leaves, walnut hulls, etc are all tanic acid and yes they would work and they accomplish the same thing…protecting from rust and elements. BUT the problen with all those above methods they will leave that dark soot on everything they touch, rub agains, or hand that holds them.
      The food acids are much more friendly and the patina stays on the knife, not on your hands. So even though the trapping methods would work I think the food mediums are better to use.

  2. Nice article, I tried adding a patina to my Skookum Bush Tool yesterday, seems A2-steel does need a bit longer to take the patina.

    Regards

  3. Hello Jason,

    I would like to take a moment to thank you for sharing your woodmanship and everyday practical knowledge. I started listening to your podcast about a month ago and I have to tell you i am hooked and honestly look forward to listening to all your future discussions. I listen almost daily on my commute and its great to learn and drive, I must say!! Thanks agian and keep up the great work its much appreciated!!!

  4. Be careful though, if you decide to use a method with hot vinegar or anything hot because I’ve heard you can soften your knife blade with that heat. I think the page I was on said if you get the knife blade above 200 Fahrenheit it can cause trouble, I don’t know for certain but don’t ruin your blade temper with the hot vinegar or anything.

  5. Im an amateur knife maker and have some experience with this subject. I do my own heat treats and tempering. The lowest temperature that I am aware of that will mess with a temper, assuming the blade has an HRC of 65 or lower, would be 400 f. Thats on O1 tool steel. If its something like A2, D2, or any other high carbon blade you are looking at more around 700f for a solid temper.

    I would also like to emphasize neutralizing the acid. Very important that you thoroughly rinse the blade after this process.

  6. this is awesome!. i started to notice the coloring on my new carbon knives changing to an interesting color but now that i know it can be controlled to a point i will use it to add a little more personality to my blades, thanks guys!

  7. I tried this on the pocket clip of a Ontario RAT1. I left the clip in heated vinegar in a jar for around an hour. It didn’t change at all. I’ve seen it done many times. What happened?

    • Pocket clips are usually made of stainless steel, and thus already has it’s own oxidized layer that prevents it from taking a patina.

  8. Thanks for the clear article, very helpful. I’m curious though, I made my own knife by stock removal and heat treating, which gave it a very durable black slag/coating. How do you remove the black slag before you would do the whole patina thing for a newly treated and tempered blade?

  9. A forced patina on a knife is lousy at protecting the steel. It’s really a stain, more than a bond, and most of it will wipe off with a wet cloth. All of it will, with enough elbow grease.

    The best protectant on steel is black rust. Red rust eats steel, and black rust protects the steel from red rust by actually binding with the steel, and leaving no way for the red rust to get to the steel, except along the cutting edge.

    The best way to protect steel is to keep it cleaned and oiled. Mineral oil works best because it’s food safe, odorless, tasteless, and colorless, and adhere to the steel better than petroleum based oils, linseed oil, etc.

    The second best protectant is a natural black rust patina, along with mineral oil.

    The third best way is a forced patina, but it does not protect very well, and you can actually rub a bare spot onto the steel when doing natural cutting tasks.

    • I disagree. I made a clone of the Camillus Bushcrafter out of O1 tool steel. I tumbled the blade in gravel and put a hot apple vinegar patina on it. The knife refuses to rust! I have a few other knives I made out of O1 and they rust easily. My future “personal use” knives will have this treatment done on them.

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