Cold Bluing a rifle barrel is not strictly a woodworking project, but since it relates to the whole aspect of gun restoration, and because we actually did cold blue the barrel, we are covering it here. Bluing is a process to help prevent rusting of exposed steel and is sometimes used on some woodworking tools as well.
We are of the belief that hot bluing is the best, at least in my experience, but it is also somewhat complicated and needs special equipment to do, OR you need to find someone who does this and again in my experience, it is not cheap.
The other thing that needs to be noted up front, is that I have seen some pretty crappy hot blued barrels and receiver plates, not because the bluing was all that bad, but because the preparation of the metal was poor. If the metal is not polished and cleaned properly it doesn't matter what kind of bluing you put on, the finished product will not look good.
To that end, we made sure that the barrel was extremely well sanded and prepared before we ever started the bluing process.
In our case we were using Outers Gun Blue Kit, a product we had never used before, so were quite interested to see how it performed, and we were ....
.. well, pretty amazed at what it did. We looked around a few different kits and finally settled on this one, not even sure why. I think it was around $15.00 and we could also have just purchased the Outers Bluing product only for around $8.00 but we decided to go for the kit because the instructions seemed a bit more concise.
BTW, you will need microscope to read the instructions, I think the font size is .003 (not sure why these manufactures think we all have the eyesight and range distance of an ant!! anyway, with some effort we finally read the fairly simple instructions.
Now before I go into the details, the only experience I have with bluing a barrel was a friend of mine, many years ago who blued a gun barrel and the product he used at that time was some sort of blue dye. I know this because he got it all over himself and the gun looked awful when he was done, I had visions of something similar but way off base with my expectations.
First of all the kit comes with 3 items, the 2.5 oz. bottle of liquid bluing compound, a 2.5oz bottle of degreaser, also liquid and pretty ordinary 1.5" x 1.5" x3" sponge and a small wad of fine steel wool. That's it, oh, and of course the instructions.
The instructions say to use the steel wool to remove rust and old bluing from the barrel, we were lucky there was barely any rust on our but the bluing was very patchy. We tried using the steel wool but it was useless for getting the old bluing off, so I resorted to using some 800 grit wet/dry sandpaper which did an awesome job. I then went to a 1200 grit wet/dry sandpaper and then finally with ultra fine steel wool. When I was done the barrel looked like it had been chromed, it was that shiny.
The next step is to cut the foam pad in half and use one half, with cold water to very thoroughly wash the grease off the gun. This is a bit of a tricky part because you can NOT touch the barrel with your fingers at this point or you will contaminate the barrel, so you need to use good quality waterproof gloves.
I should also mention that while the barrel was drying (and we wiped off most of the moisture with a clean, dry paper towel) I made a small rack out of scrap wood to hold the barrel, you will see it in the video.
Once the barrel was thoroughly dry we mounted it on the rack ... took the second part of the sponge that was left and began to apply the bluing liquid. The Outers bluing has a very faint blue color but when you apply it to the barrel there is some sort of chemical reaction that instantly turns the steel barrel, in our case, very dark blue / black. You need to keep applying fresh compound to the steel in order to get it to react with the cleaned steel. This is not like painting where you can put a thin coat on, you need to use a fair bit of the fluid, fresh with each few strokes to get the barrel blued. You will see this when you get started.
Once the barrel is blued, you need to run it under HOT water, dry off and buff it with the steel wool.
If it looks patchy, which ours did, a bit anyway, you degrease again, rinse with cold, dry and re-blue again, then back under hot water, dry off and buff.
We ended up doing this process three times and when we were finished, the barrel looked fantastic. Honestly it was way beyond our expectations.
We did notice that the next day the barrel showed a bit of oxidation, so we lightly oiled the barrel with with a soft cloth and it came back exceptionally black and shiny. We re-checked the instructions and that is the last step ... wait a few hours, then lightly oil and buff.
We know this process is not for everyone, but if you have gun, that perhaps is not worth a fortune and is, like this one a family heirloom, cold bluing may be an inexpensive option you may want to consider.
Copyright - Colin Knecht