4 Ways to force a patina on your carbon steel blade at home

To put a forced patina on your knife, you don't need a workshop or chemistry set. We are going to head into the kitchen!

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4 simple ways to force a patina on carbon steel!

Why would you want to force a patina on your blade?

Well to answer this question, we need to take a look at exactly what a patina is. For all intents and purposes, there are two types of rust that can appear on your knife. There is red rust which is bad. Red rust will flake, pit, and deteriorate your blade. It is primarily composed of hematite which is formed when iron oxidizes in a moist, oxygen-rich environment.

The other type of rust is black or blue rust. This is a patina. Black rust is primarily composed of magnetite and is fairly stable. The primary reason we want this kind of rust over the red rust is that a patina will not flake and pit your EDC blade. Not only will it not do that, but it will create a very thin layer on your blade that will help prevent red rust from forming. When someone “blues” a gun, they are using a chemical means to put a thin layer of magnetite on the steel to protect it.

While bluing is an option to protect your carbon steel blades, we found a couple really cool ways to force a patina on your blade. Not only are these techniques simple and effective, I guarantee there is a method below that you can do at home using something you already have in your house.

This stuff isn’t going to be in your workshop. To put a patina on your knife, we are going to have to head on over into the kitchen!

Mustard Patina (Acetic Acid)

Mustard Patina
Mustard Patina on 1075 Steel

This method uses the vinegar in mustard to put a nice patina on your blade. The cool thing about this technique is that you can use the mustard to easily “draw” patterns on your blade. The fact that you can spread and manipulate the mustard makes this a great choice to add a little design on your knife. We decided to test out how effective this one was. We took our Bushlore Mini by Condor (Made from 1075 High Carbon Steel) and used mustard to put a nice patina on it. Check out the video below so you guys could see it in action!

Finish:
Blotchy and unpredictable. You can get some great really nice patterning and varying coloration with this method. A nice, natural stone-like finish.
Pros:
Mustard is easy to work with and gives you the ability to make some neat patterns. 
Cons:
Messy. Can be a pain to wash off, kind of unpredictable. The smell of mustard kind of stays with the knife.

Apple Cider Vinegar Patina (Acetic Acid)

This is one of the more popular ways to patina a knife. The process is simple. All you need to so is take a cup and fill it with just enough vinegar to reach the handle of your knife. Place it in the microwave for about 10-20 seconds to warm it up a bit or warm it on the stovetop. YOU DO NOT NEED IT BOILING HOT, JUST WARM. Then all you need to do is place your blade in and wait. Check back on it every 20 minutes and remove it when the blade is as dark as you want it.

The only drawback to this technique is that vinegar is smelly. If you don’t like the smell of mustard or vinegar, keep on moving down the list! There are options!

Finish:
Nice even patina on th blade. The longer you leave it in the vinegar, the darker the patina. This method usually will give the darkest results.
Pros:
Fast and visible results. Nice even coat.
Cons:
Smells bad. Also, can have a hard cutoff of the patina where the blade isn’t submerged in the vinegar. This can be remedied by using a small paint brush to brush the vinegar up the tang.

Orange/Lemon Patina (Citric Acid)

Lemon Patina

Want something that smells better than vinegar? How do you feel about citrus? This one is super simple too. All you need to do is stick the blade in an orange or lemon and leave it for a couple hours. Oranges are less acidic than lemons so you will need to leave it in there longer. This one really isn’t any more complicated than that. Stab some fruit and see what happens. The more acidic the better. Just don’t put it back in the fridge where your kids can find it.

Another version of this is to submerse the blade in a glass of lemon juice like we did in the vinegar patina.

Finish:
Blotchy and unpredictable. You can get some great really nice patterning and varying coloration with this method. A nice, natural stone-like finish.
Pros:
Super simple and smells great. Not much cleanup. Nice patterning on the blade. Great use for an old mushy orange that is on it’s way out.
Cons:
Ruins an orange or lemon.

Potato Patina (Ascorbic Acid)

potato patina

 

This one is essentially the same technique as the lemon patina. Except for this time, we are going to just use a potato. It’s simple. All you need to do is stab the blade into a potato and wait a couple hours. Check on it periodically and remove once the darkness you want is achieved.

Finish:
Blotchy and unpredictable. You can get some great really nice patterning and varying coloration with this method. A nice, natural stone-like finish.
Pros:
Super simple. Not much cleanup. Nice patterning on the blade.
Cons:
Ruins a potato.

Does a patina prevent rust?

Well yes, and no. By definition, a patina is a rust. It’s just a more stable, thin rust that doesn’t deteriorate your blade. But the reason we want this on our blades is because it prevents the more destructive red rust from forming by cutting off access to the steel. While this patina helps prevent rust, it doesn’t make the blade rust-proof. The best method for preventing rust is a nice patina, a lightly oiled blade, and making sure that the blade isn’t exposed to the elements or moisture for any prolonged period of time. If you do all of these things, your blade will last long enough for your grandkids to use it!

Have another technique that you use to force a patina on your blade? Let us know about it in the comments below!