How to Get a Blue Patina on Carbon Steel: A Comprehensive Guide

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If you love cooking, knives must be your precious piece of the kitchen collection. Now, if you have carbon steel knives, you may see the steel tends to rust pretty quickly. As a day-to-night busy bee, it must be difficult to fix these knives now and then, leaving all other chores.

However, you can get rid of this rust and sharp routine with the blue patina. But how to get a blue patina on carbon steel?

Getting a blue patina on carbon steel is not difficult; however, a bit tricky. You can get this blue rust-relieving patina by using 3 items – a purpose-made chemical, vinegar/mastered, or ammonia. Just apply the solution over the steel, rinse, and dry. But ensure your knife is clean before the task.

Keep reading to learn more. The next segment will be very helpful for you if your goal is to have a detailed understanding of the process. So let’s get started.

How to Get a Blue Patina on Carbon Steel?

How to Get a Blue Patina on Carbon Steel

When it comes to steel, carbon steel is always on the preferred list of many.

Now, why do people choose carbon steel over stainless steel? Well, the main reason is they are strong and durable. Moreover, you can serve heavy tasks effortlessly. However, as they are mostly made of carbon, they are prone to corrosion while coming in contact with water.

Now, to get rid of the rust, people often use blue patina, an acidic layer over the blade, to prevent corrosion. This acidic layer stops the carbon in the steel from communicating with the water. So, your knife doesn’t see the face of rust pretty soon.

Getting a blue patina on carbon steel is not too complicated. You can achieve it with vinegar/mustard, ammonia, salt, or with the help of some purpose-made chemicals to create the patina.

You can also cut fruits like apples, pineapples, or kiwis.

So, without wasting time, let’s see how to get a blue patina on carbon steel using these methods.

1. Use A Purpose-Made Chemical

One of the easiest ways to get a blue patina on carbon steel is to use a purpose-made chemical. However, many different chemicals are available on the market, so choosing one designed for carbon steel use is essential.

To do the task, you need-

Step 1: Rub Alcohol on The Knife

The first step is to rub alcohol on the knife. That will help remove any grease or dirt on the knife’s surface and help the chemical adhere to the surface more effectively.

Step 2: Apply The Chemical

Once you have rubbed alcohol on the knife, you can then apply the chemical. Follow the instructions on the packaging, as different chemicals will have different application methods.

However, we recommend using Super Blue Birchwood Casey to get the blue patina, which offers guaranteed results.

Just take a brush and apply the chemical over the blade multiple times till you cover all the edges and corners.

Step 3: Allow The Chemical to Work

After applying the chemical, you will need to allow it to work. It usually involves waiting a few minutes, after which you can rinse the knife with water.

However, don’t use the knife right after the task. Wait for an hour, and your knife is all set with a blue patina and no rust.

Step 4: Apply a Protective Coating

Once you have rinsed the knife, you should then apply a protective coating, which will help to prevent the patina from being damaged or scratched.

2. Use Ammonia

Another popular method for blue patina on carbon steel is ammonia. Ammonia is a great way to get a deep, rich blue color on your steel.

For this method, you will need-

Ammonia Method.
A container big enough to fit your piece of steel in (a coffee can work well),
Ammonia (you can find this at most hardware stores or online)
A pair of gloves
A respirator

Step 1: Safety First

First, put on your gloves and respirator. As you’re worn=king with ammonia, you must maintain all the safety measures, as the chemical harms health.

Step 2: Shower In Ammonia

Place your steel in the container. Now, pour ammonia over the steel until it is completely covered. Make sure to use enough ammonia so that there is a good amount of fumes of the liquid’s surface.

Step 3: Wait and Wash

Let the steel sit in the ammonia for 24 hours.

After 24 hours, remove the steel from the container and rinse it with water. You should now have a beautiful blue patina on your steel.

3. Apply Vinegar/ Mustard

Using mustard and vinegar is pretty easy as these requirements are easily available. In fact, they are already on your shelf, waiting to help you. You can get a beautiful, rich blue patina on your carbon steel using any of them.

Things you need are-

Vinegar/Mastered Method
Vinegar/ Mastered
A Clean Cloth.

Step 1: Clean The Knife

As mentioned above, ensure your knife is clean before getting a blue patina on carbon steel. Clean your knife with soap and water, then dry it off.

You can also use rubbing alcohol to clean your knife.

Remember, a clean knife is a happy knife.

Step 2: Put Mustard/Vinegar on The Knife

Now, apply mustard or vinegar to the blade. You will get almost a similar result using any of the two. However, we recommend you to use vinegar as it will make less mess.

Now, wipe the blade with a clean cloth.

Repeat the steps till you get your preferred patina. Depending on how dark you want the patina to be, that could take a few minutes or hours.

Step 3: Rinse

After getting the desired patina, rinse the knife off with water and wipe it with a clean cloth.

Step 4: Let It Dry

Finally, it’s time to dry your knife completely. Let the knife air dry, or dry it with a clean cloth.

Don’t use a paper towel, as this can leave lint on the blade.

4. Apply Fruits/Veggies

If you are thinking “how to get a blue patina on carbon steel,” you would be surprised to know you can do it with fruits or vegetables too.

It’s easy; just cut apples, kiwis, or potatoes and keep the knife covered in their juice overnight. You will see a beautiful blue patina on your carbon steel the next day. Rinse the knife and dry it thoroughly.

Your knife is ready to use, all sharp and beautifully blue.

Why Should I Use Patina?

Why Should I Use Patina

There are many reasons to use this material, and it can be an excellent option for various applications. Here are some reasons why patina might be the right choice for you.

Enhance the Color of Your Metalwork

One of the most obvious benefits of using patina is that it can enhance the color of your metalwork. Depending on your patina, you can create various colors on your metal surface. For example, you can use patina to create a black finish on steel or a green finish on copper.

Protect Your Metalwork from Corrosion

The patina can protect your knives from corrosion. Patina forms a thin layer of oxide on the surface of the metal, which acts as a barrier against further corrosion.

Give Your Metalwork a Unique Finish

Another benefit of patina is that it can give your metalwork a unique finish that is impossible to achieve with paint or other finishes. In addition, the patina creates a random, mottled effect on the surface of the metal, which gives each piece a one-of-a-kind look.

Add Character to Your Work

Finally, the patina can add character to your work. As it’s often associated with age and tradition, it gives your metalwork a classic look.

Tips on Storing Patina Carbon Steel Knife

Tips on Storing Patina Carbon Steel Knife

Carbon steel knives are popular because they can hold a sharp edge for a long time. But they are pretty corrosive.

So, if you want to keep your carbon steel knife looking its best, you must store it properly. Storing them will help you avoid the hassle of having a rust-prone blade, which is never fun.

Here are some tips on how to store your carbon steel knives effectively.

Wash The Knife Immediately

After using your carbon steel knife, wash it immediately with soap and water. It will help to remove any food particles or grease that may be on the blade.

Dry The Knife Thoroughly

Once you’ve washed the knife, dry it thoroughly with a clean cloth. You don’t want any water left on the blade, which can cause rust.

Store The Knife In A Dry Place

Store the knife in a dry place, such as a kitchen drawer or cabinet. If you’re storing it for a long time, you can wrap the blade in a clean cloth before putting it away.

Avoid Storing The Knife In A Sheath

If you’re not using the knife for a while, don’t store it in a sheath. The sheath can trap moisture, which can cause the blade to rust.

Give The Knife A Light Coat Of Oil

Before storing your carbon steel knife, give it a light coat of oil. It will help to protect the blade from rust.

What Is The Difference Between A Patina And Rust?

Is it rust or patina over your knife blade? It’s a common confusion many come across. Now, both create a colored layer over the blade, making it confusing for a novice like me who doesn’t deal with knives more.

So, what are the differences between the two?

The blade usually has two types of layers due to oxidation: rust and patina. While another is harmless, another can destroy your blade’s sharpness.

So, knowing the differences is essential to protect your knife.

Point of DifferencesRustPatina
SurfaceCopper, Brass, sometimes silver.Iron, steel, aluminum.
Colorreddish-brown colorgreenish-blue color.
EffectHarmful to the metal because it flakes off and weakens it.Not harmful to the metal and protects it from further corrosion.


  • How do you get a blue patina on steel?

There are a few ways to get a blue patina on steel. One way is to use a chemical patina solution, which you can purchase at most hardware stores. Another way is to use a torch to heat the steel until it turns blue.

  • Is a knife with a patina safe to use?

Yes, a knife with a patina is perfectly safe to use. Many believe that knives with patina are better than those without because the patina creates a protective barrier against rust and corrosion.

Final Thought

How to get a blue patina on carbon steel? Are you still thinking about it holding the rusty knife in your hand?

Well, getting blue patina on your knife blade is not that difficult, and you can do it in several ways. You can apply chemicals, vinegar/mustard, ammonia, or cut fruits/veggies. However, no matter your chosen method, ensure you take the time to do it safely and correctly.

Blue patinas can be beautiful if you do the job carefully. Most importantly, it protects your carbon steel from corrosion, keeping them sharp and safe for a long time.