DIY Cold Bluing

Like anything else in this world that gets used, guns wear over time. Stick a gun with even the toughest coating on it in a holster and drawing it back out will slowly erode coatings and finishes. Salt in sweat, salt and humidity in the air, repeated use, metal dragging/bearing against metal as it moves and actuates, even holding a gun in the same area will eventually wear off the finish. Go into a gun shop sometime and look at the ’94 Winchesters in the rack; the balance point on a 94 is such that you can wrap your hand around the receiver just forward of the triggerguard portion of the lever. Any 94 that has been used will show signs of bluing wear (shiny, silver spots instead of black metal) right there, as well as inside the lever loop. It’s a constant in the universe:  any gun, given a long enough timeline and heavy enough use, will display signs of honest wear. And it’s not a bad thing at all; it’s a sign of a much-loved gun. However, it CAN be an eyesore, and even worse, it means that there is raw, exposed metal there, and that means that the steel is dangerously unprotected from corrosion if not properly cared for.

What is bluing?

In layman’s terms, “Bluing” is the traditional deep blue or black coloring you see on most STEEL-framed firearms. Traditional bluing only works on ferrous metals, and therefore will not work on stainless steel, or aluminum, for example. It’s a process of changing the chemical composition of the outside of the steel that the gun is made up of, chemically altering iron in the steel to form a coating of magnetite, also known as black oxide of iron. This can be achieved through a few different processes: “cold” bluing, which uses selenium dioxide to change the chemical composition of the steel, but the resulting finish isn’t as tough and wear-resistant as “hot” bluing. Hot bluing utilizes a caustic solution of  liquid alkali salts in a heated bath, usually about 295-325 degrees F, and the resulting caustic black color is much tougher than cold bluing, but necessitates lots of specialized equipment – all the big time gun manufacturers utilize hot tank bluing because it’s a reliable, cost-effective way to produce high quality results that are attractive and rust-resistant. I used hot-tank bluing to refinish guns for years at a local gunsmithing shop, and I can tell you, it’s a dirty, dangerous process. One drop of that caustic salt solution at 300 degrees will put a hell of a burn on you. There are lots of environmental issues with cleaner and salt bath disposal; this is why you end up shelling out the big bucks for a professional reblue job.

There are other methods, such as rust bluing , fume bluing, and carbona bluing,  that turn out truly beautiful and extremely durable blued finishes, but they are very labor intensive and generally only employed by trained, experienced gunsmiths. There are myriad other finishing options, such as parkerizing, sprayed-on finishes like Duracoat and Cerakote, and nickle plating. However, all of these are out of the reach of run-of-the-mill guys like you and me, as they are either expensive to have done, or expensive to buy the necessary equipment and training to do it ourselves.

Going the Easy Way

So, what does this mean for us if we want to keep our firearms looking snazzy, and keep them protected, yet don’t want to pay the $150+ bill to have a gunsmith refinish our guns? Well, a quick and easy way to re-finish our steel guns is with cold bluing. No, it’s not as durable as the other types of bluing, but it has the advantage of being very inexpensive, and relatively easy to apply, even by the novice. There are couple things to watch out for and attention to pay in certain areas, but there’s no reason why, with a little patience and attention to detail, anyone reading this can’t do it on their own.

What You’ll Need

Aside from the aforementioned patience, there are a few items you’ll need to accumulate. First, a few grades of sandpaper (400 and 600 grit) and/or Scotch-Brite metal finishing pads (maroon colored ones are a good bet) to polish the metal and remove and crust and rust scale. Non-VOC brake cleaner (doesn’t leave a residue as it de-greases) or acetone, to de-grease the metal and generally clean it; #0000 steel wool for burnishing the metal between applications; cotton balls for applying the cold blue (clean cut-up sections of an old t-shirt works well too.), and a good, high-quality gun oil will be needed.

Of course, you’ll need cold bluing! I’ve used a couple different types, and both worked well: Birchwood Casey Perma-Blue has been pretty good to me in the past, but I generally go for Brownell’s Oxpho-Blue if I have my druthers. There are other products out there, such as a bunch of other Birchwood Casey products and Kleen Bore Black Magic, that I’m sure work just as well if they’re more available to you.

Most of these will come in a liquid form, but some come in cremes or pastes which probably cling a little bit better to the metal and possibly would be a bit easier for the beginner. However, I’ve never found the liquids to be hard to use, so I’ll leave that one up to your discretion.

Getting Started

To kind of have a visual display as to what’s going on when we cold blue, I pulled the butt-plate of my father’s old, beat up Remington Model 14 that has seen many, many days in the woods. The steel butt-plate had some severe crust built up in the horizontal grooves that were in the surface of the plate, plus pretty severe wear, from being shouldered thousands of times, and leaned against trees, or whatever handy field prop was around when the rifle needed to be set down.

First, we need to remove all the old bluing, and any built-up rust and crust. Any foreign contaminants could possibly ruin our hard work down the road. To remove these, I usually first use steel wool soaked in gun oil or WD-40 to break down the rust and grime, and get it out of tight spots, the the grooves you see in the butt-plate. A wire brush, a fine wire wheel on a bench grinder, or any other number of light abrasives that won’t remove a ton of metal when you use them, will work well too; no saying you can’t use combinations of anything you have to get the metal down to just metal. Once the crud is cut out, you can use 400 grit sandpaper to get the old bluing off. If you find big, deep pits, you might want to look into buffing wheels with polishing compounds to get those out; but for now we’re going to assume that the pits were removed by sandpaper and a little elbow grease. Next, use a higher-grit sandpaper or a green Scotch-brite pad, followed by a maroon Scotch-Brite pad to polish the metal up and make it snazzy. We’re looking to take the the entire surface of the part down to bare metal.

Once everything is cleaned up, you’ll be pretty grubby, but the metal you’re working with should be nice and shiny, bright silver.

You can still see some light pits on this butt-plate, but I’m personally not really concerned about those; this is a working gun.

The next step is the most important, and as any car painter or gun refinisher will tell you, grease, oil, and silicone are the enemy! We need to eradicate these from the entire surface of the part you want to re-blue, or you’ll get bleed-through and discolorations that are very tough to work through without starting from scratch. So, trust me: It’s best to do it right.

I like to start by giving the part(s) a good healthy dose of aerosol brake cleaner to blast all the oil, and any broken loose crap, off the surface of the part. Give ‘er hell; brake cleaner is cheap and it really works. However, it can leave a light, dry residue that also will wreck our bluing job. So, when I can, I also wash the whole part down with acetone and let it air-dry.  Make sure you clean your hands before and after you do this; oil from your skin can and will discolor the parts! While you’re brake-cleaning parts, drench a bunch of your #0000 steel wool and let it air dry. Steel wool comes with a light coating of oil on it to keep it from rusting…and guess what? THAT will mess up your bluing job, too!

Once everything is super clean, get out your cold blue (whatever form you purchased) and your application cloth or cotton balls. If you have rubber gloves, don them. It’ll keep the bluing solution off your skin, and your skin oils off the parts.

Go ahead and soak a cotton ball or patch with the cold blue solution. Really drench it. (this can be messy; be sure to have a wipe-off rag handy, too!). Then, rub that soaked cotton ball all over your nice, shiny, clean steel part…and watch the magic happen.

Yep, it turns colors! But it will be splotchy colors. Kinda discouraging. But keep at it; keep running that soaked applicators all over the part, not letting the cold blue solution dry or settle on any one part; this will create darker spots. This isn’t the end of the world, but the more even you can make the application, the easier it will be.

You’ll see it doesn’t get super black instantaneously; this will take several “coats”, if you will. It’s VERY IMPORTANT for a nice, clean, even finish that you don’t let the cold blue solution sit on the part for more than one minute or so; it will keep those discolorations in the metal. once you’ve gotten the first application on the metal, take a clean, lint-free cloth and wipe the whole part down, getting the solution off. You can rinse it with water if you want, but I usually shy away from that since the part really isn’t that protected yet.

Next, after drying the part thoroughly, grab your #0000 steel wool and polish that metal you just cold blued. This is called “burnishing” and it helps to really up the quality of the bluing job you do. It looks like it’s taking off the finish you just applied, but go lightly and you’ll soon find a happy medium that looks good and keeps the finish. Clean the part again with acetone, to get any steel wool fragments and any other crud off, and let air dry.

Wet the applicator down again and repeat the process. Wet, dry, burnish, clean. You’ll notice that the more you do this, the “brighter” the polish will be, and the darker the blue will get.

Soon, the finish will be at a level you find pleasing.

It may take a couple hours and all your patience, but eventually, the hard work will pay off. Different tempers and alloys of steel will blue easier or harder; you never really know until you try it. But keep at it, repeating the process, and eventually, the dark blotches will work themselves out, the rest of the metal will even out, and your metal will look great.

After the hard work

Once you have the metal to the point you’re happy with it (the above butt-plate took about two hours, beginning to end) you’ll need to protect your hard work. Be sure to clean any remaining residue off, and then coat it heavily with gun oil. Let the gun oil work into the pores of the metal – heating the part at low temperature in your oven – say 170 degrees F or so, to expand the metal and open the pores will help, before you apply the oil. The metal will cool, trapping the oil inside and keeping the metal protected. The oil will also help bring the color out a bit, you might notice.

Keep in mind, like I said before: cold bluing is not as durable as standard hot-tank bluing or many of the sprayed-on finishes that are available. However, you can do it yourself, it’s aesthetically very pleasing, and it protects your gun. What’s wrong with any of that? It may not be a SHTF skill per se, but if you use your gun (which is a huge investment) it pays to be able to keep it looking great and protected for when you do need it.

As a side note: Bluing doesn’t HAVE to be just on guns. Anything that’s carbon steel can generally take a nice bluing: hatchet heads, knives…you name it. I have a REALLY snazzy hatchet around here someplace that I blued in a hot bluing tank years ago…and DAMN, does it look good! I’ll have to dig that out someday…

Do any of you do at-home refinishing? Is it a waste of time, or worth your time? Would you try cold-bluing, or does Krylon and Rustoleum take care of what you need in the finish department?

Stay safe!

-Road Warrior

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All photos by Road Warrior