Cold Bluing

My old Marlin 43 shotgun had the barrel’s bluing faded to a brown patina and the magazine tube had areas worn to bare metal by the slide. Fortunately, the bluing on the receiver was still in good condition. I have used cold bluing for minor touchups such as scratches and refurbished screws but not on a large scale such as a barrel. After doing some research on the various brands, I chose Birchwood Casey Super Blue. Prep As with any refinishing project, proper surface preparation is key.

After removing the barrel and magazine tube, I cleaned them thoroughly with acetone to remove any oil or dirt. Alcohol (denatured or isopropyl) and brake cleaner will also work. Do not use a solvent that leaves a residue. I removed the old bluing with 400 grit sandpaper. Using a curved backer, I sanded along the length initially to get rid of the old finish. I then used 600 and 800 grit paper and sanded circumferentially to polish the steel.

A simple fixture Faded bluing on the barrel and magazine tube band (bottom). of two V-shaped blocks and a pair of dowels supported the barrel and magazine tube while sanding. After polishing I cleaned the parts again with acetone. Cold Bluing Protective gloves and eye wear are required when using the cold blue liquid. You also don’t want to touch the cleaned surfaces with your bare hands as it will leave oil that will likely show up on the finish.

While I’ll refer to the barrel in the rest of the article, the magazine tube and the action bar were done in the same manner. I applied the bluing liquid with a 1" wide foam brush, putting on a heavy coat with plenty of overlap. It turns the bare steel a dark blue

Instructions for use are on the label (not shown). immediately so it’s easy to see the area that’s been covered and any spots you missed. After 30 seconds, I rinsed the barrel with cold water, using a wet cloth to wipe it down. I used a gallon of distilled water in a five gallon bucket. Distilled water is not required but I didn’t want to take any chances with tap water and its chlorine. After each application of the bluing liquid, I rinsed the part in cold water with the ends of the barrel plugged with corks.

The barrel has a magazine tube band that I used as a handle when holding the barrel. 1914 Flues Sx S I read "Ithaca Flues Shotgun" (April 2020) by Mark R. Hollensen with great interest. Not to contra- I dried the barrel with a cloth towel and then used a heat gun to get rid of any residual water. The dried bluing is splotchy and uneven but that’s OK. Four-ought steel wool (degreased with acetone if necessary) is used to scrub off the excess bluing and polish the finish.

If the finish still looks uneven, keep polishing with the steel wool. Clean again with acetone. I noticed that I had missed a few spots so I applied a second coat. After rinsing and polishing, the barrel color did not seem any darker but the finish was more uniform. I gave dict, but readers may be interested in how different two Flues model shotguns manufactured just two years apart can be. the barrel a third coat for the heck of it. The finish was then a very dark blue and very even.

After the final polish and cleaning, a coat of gun oil was applied to halt the bluing process and then wiped dry. A second light coat of oil was added a few hours later. The new bluing on the barrel, magazine tube, and action bar closely matched the old bluing on the receiver. Cold bluing the old barrel and magazine tube made them look like new and the finish was comparable in color—but probably not durability—to a newer shotgun with its hot blued finish.

Cold bluing is not a replacement for hot bluing but for the everyday firearm and the do-it-yourselfer, it works very well. It’s a simple process, it doesn’t take much time, and the results are worthwhile. AG My Flues shotgun (SN 2434XX) built in 1914 is a 12 gauge model with "SMOKELESS POWDER METAL" engraved on both barrels forward of

the breech. Measurement revealed it’s a 2 3/4" chamber. The individual I purchased the gun from told me he’d hunted with it for quite awhile and I’ve put plenty of shotshells through it, mostly shooting trap. I’ve disassembled my gun and replaced one firing pin. I meant to replace the other as well but that firing pin screw would not budge. I needed to replace the principle wood screw under the breech lever and lucked out when I purchased a one-pound bag of screws from Numrich.

In addition, the stock was about an inch short for me but I found a spacer on Numrich. Ideally you’d want to add it to the end of the stock, but I needed to cut the stock about an inch forward of the butt plate which added about 3/4" to the length of pull. The barrel chokes gauge at 0.707" and 0.712", which I thought strange, though both are in the modified to improved modified range. I can actually place a dime on top of the smaller bore and it’s just snug enough to prevent it from falling through.

Author Mark Hollensen responds. Interesting! I suspect that they made the 2 3/4" chambers for the 12 gauge much earlier than the 16 gauge guns and this reflects that. I know folks continue to shoot Flues shotguns without problem. The greatest concern is the fact that shotshells made in that time period (before modern ammo came onto the scene) utilized cardboard wadding separating the powder from the shot. The cardboard lets gases pass by when firing allowing pressures further reduced in the bore.

Modern shotshells have a plastic wad that seals up the bores when fired, greatly increasing pressure from that alone since gas cannot escape past the wad before it comes out of the barrel. That is the primary reason I hesitate to shoot these guns and advise against shooting such old, classic arms. This is especially true if the bores have severe rust pitting inside of them.

Note, some of the old shotguns had the chambers lengthened when 2 3/4" shotshells took over the market, so there is always the possibility that the chambers were lengthened on your shotgun. It would be very difficult to tell if that is the case. Thanks for your information about your Flues.