How to Blue a Gun For a Better Looking Firearm

How to Blue a Gun for Display and Longevity

If you're into guns, you're likely familiar with the term bluing before. After all, different forms of bluing have been used by gunsmiths and hobbyists for years. This technique helps protect guns from natural wear and tear. Bluing is when you treat steel to make a protective coat around it. It works by transforming red oxide rust surfaces into black iron oxide. That's why the process is also called black oxidizing. You can perform the bluing process mainly on gun barrels. But they also work with other firearm components. So, you may be wondering, how to blue a gun? 

There are multiple ways to blue gun barrels. These include hot bluing, cold bluing, fire or heat gun bluing, rust bluing, fume bluing, and niter bluing. With that in mind, here's a detailed guide on the cold-bluing process. 

The Gun Barrel Bluing Goal

Gun bluing is mainly used by gunsmiths, gun owners, and manufacturers to improve the cosmetic appearance of firearms. The goal of gun barrel bluing is to provide corrosion resistance to guns. But the bluing process can also help maintain a gun's metal finish by resisting superficial scratching. It helps reduce glare to the shooter's eye when looking down at the barrel of a gun. However, remember that blued parts still need oiling to prevent rusting. 

It's worth noting that since bluing involves chemical conversion, it's not as strong against wear and tear or corrosion. That's because it's typically not bigger than 2.5 micrometers. So it's best not to add any bluing solution to precisely-machined gun parts.

But by rebluing your gun, you can help prevent rusting. That'll ultimately make it more challenging to maintain your weapon's value down the road. Another reason why you should reblue your gun is that you'd want to ensure you retain your gun's functionality. 

But, do you need to hot blue your gun? The truth is, it's up to you. Bluing only works on raw steel, cast iron, and does not work on non-ferrous metal. After all, when you first bought your weapon, it should've come with a thin protective shell of iron oxide, giving your firearm that sleek and professional feel and looks. However, over time, this coating can fade, ultimately leading to gun rust. Without rebluing your gun, you'll see that it'll begin to lose its luster faster. Additionally, you do not need to blue the whole gun. Some rifles have silver solder on the rear sights, and this requires a separate process. So instead of buying a new weapon, you can always reblue your firearms.

Bluing Solutions to Choose From

Gun bluing is a traditional finish that people apply to their firearms. It protects the steel from corrosion, giving the metal a dark blue finish. Factory bluing processes haven't changed much over the years, and gun owners can now buy home bluing kits and solutions to refinish their collections. That said, there are different bluing solutions to choose from, and here are the most common ones: 

Hot Bluing

The hot bluing process uses an alkaline solution. It's applied to the steep parts of the gun and done by dipping these into the alkaline solution that contains sodium hydroxide and potassium nitrate. When completed, hot bluing will give your weapon a sturdier and more attractive finish. For this reason, hot bluing is commonly used by gun manufacturers on factory-blued firearms.

Cold Bluing

Cold bluing is a process mainly used for cosmetic touch-ups of previously blued guns. There are many cold-bluing solutions to choose from since they work to enhance existing blued guns. The difference between hot bluing and cold-bluing is that the latter is usually sold in smaller bottles and is applied using a carding brush applicator. Meanwhile, with a hot bluing solution, you only need to dip the gun into it.

Additionally, cold bluing solution can be lightly heated after application to increase the gun's durability. Overall, though convenient, cold bluing isn't as efficient as a protective shell as hot bluing. But for aesthetic touch-ups, it's the best solution. 

Rust Bluing

The rust bluing solution is a more traditional bluing process. It's not used as much anymore. That's because the rusting process involves applying an acid solution to the steel gun part, causing it to rust. After this part rusts, you'll need to neutralize the acid with boiling water and scrub the loose rust off with steel wool, leaving a blued finish. Most antique firearms were finished with the rust bluing method up until the invention of hot bluing. 

Fire Bluing

Fire bluing involves heating a polished steel part until the metal surface changes to a deep blue color. Although this method isn't as durable as hot bluing, like cold bluing, fire bluing can be done at home with existing bluing solutions. As a result, fire bluing produces a colorful and attractive finish. It's ideal for small gun parts or restorations. 

Fume Bluing

Fume bluing is the process of rust-bluing steel, producing a tough corrosion-resistant coating for steel. Gun manufacturers often use this solution, but you can also do it at home. Although fume bluing takes a bit more time than other solutions, it develops excellent coating. 

Niter Bluing

Niter bluing involves immersing polished and cleaned steel parts in a bath of molten bluing salts. These include potassium nitrate and sodium nitrate. They’re often heated past their melting point of 633.2°F to color the steel. It's a bluing solution that you need to observe for a color change constantly. You can't use niter bluing on critically heat-treated parts like the receivers, springs, or slides. That's because it's generally applied on smaller pieces such as pins, screws, and sights.

Hot Blued Barrel

Hot bluing is the most common bluing method used by large manufacturers and gun enthusiasts alike. That's because it produces a very durable finish on top of the gun's finish. The main advantage you'll get from the hot bluing method is gun protection against correction, extending the life of a firearm and restoring it. That's said, here's how to produce a hot blued barrel.

1. Disassemble and Polish

Using steel wool, remove any loose rust and scarring on the gun's arm metal. If needed, you can use a rust remover to clean the gun of any corrosion. Then, take the entire gun apart. Anything you don't remove will get salt embedded in it. When this happens, it will be more challenging to disassemble after bluing steel. Besides that, you also need to remove all the springs you don't need to blue. Additionally, the items used in the hot bluing method are caustic chemicals. So practice caution and always wear rubber gloves when working with them to avoid getting severe chemical burns. 

2. Soak and Rinse

After disassembling and polishing the gun, it's time to dip them. All parts should be immersed in the bath for at least 15 minutes. When soaking them, make sure to scrub them with steel wool to remove any excess dirt, oil, and grease. That's because these can get in the way of the bluing process. You can use any chemical cleaners for this step, such as denatured alcohol, naphtha, and acetone. Rinse the cleaning solution in a couple of minutes. 

3. Immerse the Gun Metal Components in the Bluing Solution

The bluing solution for hot bluing is made up of a caustic salt mixture. The main ingredients in this solution are potassium nitrate and sodium hydroxide, which get heated past their melting point to color steel. This combination is known as 'traditional caustic black.' When immersing the metal components in the solution, the caustic salt mixture needs to be warmed in a metal basket to temperatures between 275°F to 310°F. Then, let the gun parts stay in the solution for 15 to 30 minutes. 

After the allotted time, double-check to see if the metal has reached the desired color tone of bluing. Usually, red iron oxide rust forms on the surface, leaving a black oxide finish underneath it. When this happens, remove the rusted surface using steel wool to reveal the black iron oxide beneath. This process should give you the blue-black appearance you need. When you've achieved this, remove the parts from the traditional caustic black solution. 

4. Rinse with Cold Water

After immersing them, rotate the gun parts through cold water to wash off the blueing salts. After washing them thoroughly, let them air dry for at least 3 minutes. 

5. Boil

After rinsing the parts in cold water, put them in boiling water. Doing this helps remove any remaining bluing solution. Primary gun parts like the barrel need to be soaked for around 25 to 30 minutes. Meanwhile, complex or decorated parts need to be boiled for 45 minutes. Make sure to submerge them in water at the boiling point (212°F) for the best results. 

6. Finishing Touches 

After boiling the parts, soak the treated gun parts in a bath. Doing this protects the gun's finish from sweat, rust, and body oil. It's best to let them submerged in a cleaning oil bath for an hour or until they've cooled down. 

Advantages of Hot Bluing

Hot bluing involves metal parts being placed in a mixture of chemicals heated around 150°C (302°F). As a result, it produces a black oxide compound known as magnetite on the mental surface, providing corrosion and rust resistance. That said, here are the most notable advantages of hot bluing: 

  • It's a process best suited to large-scale bluing by manufacturers. Although you can replicate the process at home, it isn't always the best for individual cases due to the high temperatures and corrosive chemicals. 
  • Hot bluing is the standard bluing process in gun bluing. That's because it is the most efficient in developing rust resistance and protection to gun-metal.
  • The method also provides a measure of corrosion resistance to guns. 
  • It helps maintain the metal finish by resisting superficial scratches.
  • Hot bluing helps minimize glare to the shooter's eyes when looking down the gun's barrel. 
  • Unlike other methods like rust bluing, where you need to scrub off the rust with steel wool or use a brush applicator like cold bluing, hot bluing is more convenient. It's a simple process. All you need to do is dip the gun parts that need bluing in a hot bluing solution. 

The Cold Bluing Process

The cold bluing process doesn't require heat. So this method isn't ideal if you're looking to toughen up your firearm. It's not resistant to holster wear nor provides rust resistance. This process is usually done for cosmetic purposes. Generally, it provides a cosmetic retouch of a firearm's finish when applied and oiled regularly. But rust bluing of small parts will usually hit the bluing target better than other cold blues. That said, here's how to cold-blue a gun. 

1. Clean and Polish

Polish the gun-metal surface with sandpaper or steel wool as you'd do with other bluing processes. But how you clean the arm depends on whether you need to blue the entire gun or improve existing bluing. 

2. Use the Bluing Solution

After cleaning and polishing the parts, spread the solution to the part evenly. There are plenty of cold blue solutions to choose from, so decide which one is best for your gun. Regardless, it's best to use a clean applicator like a cotton ball or a proper carding brush. Then use the solution in a single pass, covering small parts. Meanwhile, when covering larger areas, make sure to smooth them out using sandpaper. Doing this prevents the bluing from looking messy. 

Repeat applying the solution until you get your desired bluing result. Similar to other methods, it should look like it has a blue-black appearance. Finally, wearing rubber gloves is also recommended for cold bluing since the metal surfaces might get body oil and other chemicals. 

3. Make Fine Adjustment

Finally, you can further improve the finish with gun oil. Make sure to apply this once you achieve your desired bluing level. Do this by spreading a layer of oil a couple more times. It's best to use a clean cotton ball to remove the previous existing layer before applying a new layer. Keep in mind not to apply cleaning oil at this stage since it'll take off the bluing. 

Advantages of a Cold Blue Barrel

Cold bluing doesn't need heat, and you can do this process at home. You can find many commercial products for this method at local hardware stores or gun shops. These are mainly used to apply minor touch-ups to the firearm's finish, treating rust surface and preventing scratches from becoming a significant source of rust on the weapon over time. Here are the advantages of a cold blue barrel: 

  • Cold-blued barrels are resistant to superficial scratching. 
  • They can reduce the glare to the shooter's eye whenever they look down at the barrel. 
  • Since you can do cold bluing at room temperature, it's possible to do this in any place. 
  • It doesn't affect the measurements of the blackened objects. 
  • The process can be done at home since you only need store-bought solutions. 
  • It's a simple process that only requires degreasing, activating, and bluing. 
  • It provides proper cosmetic touch-ups. 

Gun Bluing Products

Bluing enhances the appearance, specifically the metallic shine of guns to protect the metal finish from any superficial scratching. Even the highest quality guns to older pieces like vintage shotguns will benefit from regular bluing. Luckily, bluing kits are now readily available so that you can do the blueing process at home. That said, here are the top gun bluing products you should consider. 

Birchwood Casey Super Blue

This product comes in a 3fl oz bottle which is the perfect amount to last you for months, even if you use it regularly. It's one of the best products for cold blues since it has the highest quantity and is versatile. Whether your gun has more rigid metal or normal iron and steel, this product will work like a charm. After all, this was developed to use on different materials. 

The product comes with an instruction manual, but even beginners can use it without any problem. You can use a brake cleaner, gun scrubber, or regular steel wool to get good results. For standard gun blues, you need to keep applying the solution repeatedly to get the desired results. However, with Birchwood Casey Super Blue, you only need to use it two to three times to get noticeable results. 

In short, this product will help your guns become sparkling or matte with ease, even if you have a larger firearm.

Van's Gun Blue 

Gun bluing has never been easier, thanks to Van's gun blue. This product can penetrate through steel, unlike other gun blues. For this reason, it provides a durable finish to metal parts. When you use this kit, you'll notice that the resulting bluing will perfectly blend with the original color, making it look more natural. Regardless, you're guaranteed to get a decent finishing to your gun. 

But like most bluing products, you'll need to use them several times to get the desired output. However, you don't need to worry since this product lets you get the best bluing results with ease. So, you can use it for months. It's best to apply Van's gun blue by using a towel or steel wool. 

Perma Blue Liquid Gun Blue

This blueing solution gives you an easy way to touch up any scratches or worn spots on your gun. Plus, it can entirely reblue your firearm with ease. It'll provide a non-streaky and perfect blue-black finish to steel. The Perma Blue liquid gun blue offers excellent bluing for metal that's been thoroughly cleaned and is rust-free. However, this product can't blue stainless steel, aluminum, and non-ferrous metals. 

Oxpho-Blue Professional Grade Bluing Solution 

Whether you're looking to achieve a glossy or matte finish, you can do both with this bluing kit. However, keep in mind that this finish will depend on the gun's surface. For instance, the gun surface will give a matter look if it has a sanded surface. In contrast, if the gun has a polished steel surface, you'll achieve a glossy look. But you can only use this for touch-up jobs. That's why it's not recommended for cast iron.

It can damage the material's quality. However, for other materials like polished steel, this one works perfectly. When applying this blue, you'll need to douse it in cleaning oil to achieve better results. Finally, to get the perfect finish with the product, you need to bead blast your gun's slide. Doing this gives your firearm a black aluminum touch-up, making it look and feel great.

Delta Provision Gun Cleaning Kit

This bluing kit is universal, meaning it can help maintain and clean all firearms. These include simple weapons like a revolver pistol to more complex pieces like double-barreled shotguns. But regardless of the gun you own, you can achieve decent finishing with Delta Provision Gun Cleaning Kit. It offers an organized and tactical system, making maintaining and cleaning a breeze. So not only can you clean your gun easier, but it'll also be quicker. 

The best part is that the case's design and the tools in this product are compact, allowing you to bring it anywhere you want. Plus, it's PALS and MOLLE compatible. Additionally, if your guns have scopes, you'll need to clean the lens too, and this product comes with lens pen cleaning options.  

Choosing a Gun Oil

Gun oils serve different purposes. For instance, some are made to lubricate rusted parts, while others are made to protect the thin protective shell of the gun's finish. That said, there are certain factors you need to consider when choosing gun oil. Here are the following factors that'll dictate the performance your gun will deliver. 


Grease is applied to certain gun parts to prevent corrosion and rust, like the gun barrel. The best gun oil solutions contain anti-corrosion properties. You can improve the precision by buying all kinds of gun oil and applying them depending on their needs. 


Viscosity is crucial when choosing gun oil. That's because highly viscous oil typically flows slower than low viscous oil. So when applying the oil, less dense variations run away faster from the points of applications, quickly seeping to the different parts of the gun. That's why if you're looking to achieve better control of the components you need to oil, it's best to choose highly viscous oil.

Extreme Pressure/Anti-Wear

EP/AW is present in some of the highest quality gun oils, ensuring the gun can operate smoothly. This additive is added to the best gun oils to deliver optimal protection and performance. It contains tiny solids mixed with oil, boosting the thickness and adding extra features to it. You'll find that many mixtures are tailored to suit particular gun needs, environmental factors, and other concerns. 


When choosing a gun oil to help you blue a gun, thickness is a crucial factor to consider. That's because thickness matters regarding the climatic condition where you'll be using the weapon. Generally, thinner oil is better in colder climates since they speed quicker on the gun parts, making them more efficient in curbing friction since it won't rub off easily. But in humid and hot climates, thick oil is better. That's because they can stick to the gun's polished or surface rust and won't be vulnerable to evaporation.

Oil Color

Although oil color may seem irrelevant, it's a crucial factor. That's because, as mentioned earlier, you need to apply the oil evenly on the gun parts. So that means you need to perform the process in a place that's well lit, meaning darker-colored oils can be hard to use in darker areas. After all, you don't always get to oil your gun in ideal conditions. 

How to Use a Cleaning Solution

Besides knowing how to blue a gun or black oxidizing, you should learn how to use the cleaning solution that comes with treating steel and other gun parts. Here's a step-by-step guide to cleaning a gun with a cleaning solution:

  1. Begin by cleaning the gun's barrel using patches or cleaning rods. Then soak the bore using a patch holder or cleaning rod. It's best to start from the back of the bore to prevent the rod from damaging the muzzle. 
  2. To ensure the barrel's cleaned correctly, push a patch soaked in a cleaning solvent across the bore to the opposite end. Then after a few seconds, remove the patch. 
  3. When scrubbing the gun's barrel, remember to alternate the patches and bore brush to clean it thoroughly. Run it 2 to 4 times along the bore so it can remove any surface rust. 
  4. After, fix the patch using cotton soaked in cleaning solvent across the bore and remove them from the other end. Repeat the process until the patch comes out clean. 
  5. When the patch comes out clean, run a dry patch to dry up the bore. 
  6. When thoroughly dried, apply oil on the barrel using a cotton swab attached to a rod, then run it across the bore. You can use a soft wire to let the brush reach awkward spaces. 
  7. After applying the thin layer of oil, follow it with lubrication and brush every part using a gun brush with a cleaning solvent.
  8. Wipe the same parts to dry using a clean cloth. 
  9. Apply a tiny amount of oil to the moving parts. Doing this helps prevent rusting. 
  10. Then, use a lubricant pre-treated luster cloth to wipe the other parts of the gun and remove the remaining debris. 

Overall, gun bluing turns a worn weapon into one that almost looks as good as new. We hope this guide helped you learn more about bluing and its importance to firearms, helping you get the most out of your gun. 

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