Bluing is a thin protective layer of black iron oxide (Fe3O4) applied on gunmetal to give minimal rusting prevention. However, over time, this shell will deteriorate and need to be replaced to restore the gun’s appearance. You can either have the pistol professionally re-blued or repair the bluing yourself, depending on the pistol’s age, monetary value, and sentimental worth.

How to Reblue a Gun: Decide How to Restore the Bluing

Take a look at how much of the old bluing has faded. If the majority of it is still intact, a cold-bluing kit may be used as a touch-up. If most of the original bluing has worn away, try removing the remaining bluing and hot bluing the gunmetal.

Consider the gun’s age. The rust bluing or fume bluing processes were used to blue vintage guns dating back to the 19th century. Because of the time necessary, these methods are not employed commercially nowadays. There are commercially available products that will allow you to do the rust bluing process yourself, or you can hire someone to do it for you.

Take into account the gun’s worth. Because hot bluing is more expensive than cold bluing, you must weigh the cost of the re-bluing technique you want to utilize against the cost of the gun itself and its resale value if you decide to sell it.

Consider the bluing process’s possible expense. You should evaluate the costs of the bluing process you are considering adopting in addition to the monetary and intrinsic value of the gun that has to be re-blued.

Cold Bluing

Step 1: You can remove the old bluing

You may want to remove the previous bluing altogether before re-bluing the gun, depending on how worn it is. To do so, you can utilize one of the following chemicals:

Naval Jelly is a phosphoric acid-based vehicle rust remover.

Acetic acid is found in white vinegar.

Step 2: Polish the gunmetal

Polishing the gun removes surface rust as well as any scratches or pitting that have developed over time. For this, you can use either 000 steel wool or 600 to 1200-grit sandpaper.

Step 3: Clean the gunmetal

Whether you plan to blue the entire rifle or just touch up existing bluing will determine how you clean the metal.

Step 4: Heat the metal gently

Even though this is referred to as cold bluing, gently heating the gunmetal before applying the bluing can help it absorb the bluing more effectively and produce a nicer finish. Heat the metal by leaving it out in the sun for several hours, using a heat gun or a blow dryer, or using the lowest setting on a regular oven.

Step 5: Apply the bluing solution

Using a clean applicator, slowly apply the solution to the area to be blued as evenly as possible. To cover tiny areas, apply the solution in a single pass or in sections no larger than 2 to 3 inches (5 to 7.5 cm) when covering larger areas, then smooth it up with steel wool. The bluing will not appear speckled as a result of this.

Step 6: Apply the solution several more times 

Apply the solution a few more times until you achieve the desired level of bluing. Each layer should be applied with a new applicator, and each new coating should be smoothed down with a new piece of steel wool.

Step 7: Season the finish with gun oil 

Once you’ve achieved the desired level of bluing, season the finish with gun oil. Apply a layer of gun oil every few hours, removing the previous coat with a cotton ball before adding a new layer. (In other words, instead of using water, you’re using gun oil to wash away the bluing solution.)

Hot Bluing

Step 1: Polish the gun parts to be blued

To polish the metal, you can use either 000 steel wool or 600 to 1200-grit sandpaper.

Step 2: Prepare parts to be dipped in the cleaning and bluing solutions

While the cleaning solution you’re using may not require it, the chemicals used in the hot bluing process itself, which are often potassium nitrate and sodium hydroxide, are quite caustic. Threading soft wire through the gun barrel will make it easier to dip it, and putting the smaller components in a wire basket will make it easier to dip them.

Step 3: Bathe the gun parts in a cleaning solution 

Parts should be soaked in the water for 10 to 15 minutes while being cleaned to remove any oil, grime, or grease that could obstruct the bluing process. You can use any of the chemical cleaners indicated in the cleaning stage for cold bluing as long as you read and follow all of the cleaner’s instructions for use, handling, and disposal.

Step 4: Rinse off the cleaning solution in cold water

It should just take 2 to 3 minutes to rinse.

Step 5: Dip the gun parts in the bluing solution

The hot bluing solution, also known as “Traditional Caustic Black,” must be heated between 275 and 311 degrees Fahrenheit (135 to 155 degrees C).

Step 6: Rinse off the bluing solution in cold water

To assist wash away the bluing salts, swirl the components in cold water.

Step 7: Immerse the gun parts in boiling water

Any residual bluing solution residue will be boiled away. Simple pieces should be immersed for 5 to 10 minutes, while more intricate or ornate pieces could take up to 30 minutes.

Step 8: Immerse the treated parts in a bath of water-displacing oil

This will keep the finish from rust, sweat, and body oil. Place the components in the oil bath for 45 to 60 minutes or until they are completely cold.

Rust Bluing

Step 1: Polish the parts to be blued

To remove any loose rust, scarring, or pitting from the gunmetal, use steel wool or 600 to 1200-grit sandpaper.

Step 2: Clean away any dirt, oil, or grease that remains chemically

Unless the maker of the rust bluing solution you’re using indicates otherwise, you can use any cleaners specified in the cleaning phase under the cold bluing method. Rinse the cleaning solution when you’ve finished using it.

Step 3: Coat the gunmetal parts with the rust bluing solution

Hydrochloric and nitric acid are commonly used in rust bluing solutions. In fact, this treatment stimulates the metal to rust, but in a uniform manner.

Step 4: Immerse the gunmetal parts in boiling distilled water

By eliminating the acid solution, the rusting process is halted.

Step 5: Scrub away the red oxide rust that has formed, leaving the black oxide finish underneath

A carding brush or wheel with very soft and thin wire bristles is typically used to remove surface rust.

Step 6: Repeat the acid treatment, boiling, and scrubbing until you have achieved the desired level of bluing

Further bluing attempts may be unproductive if the metal develops as deep a color as it can.

Step 7: Coat the gun parts with oil

Rust is prevented by the oil, which also protects the metal finish from dirt, sweat, body oil, and wears. Allow the components to soak in the oil overnight before putting them together.

🤔 How to Restore the Bluing?

Take a look at how much of the old bluing has faded. If the majority ...

🔍 Cold Bluing

You may want to remove the previous bluing altogether before re-bluing the gun, depending on ...