Metal polishing: before refinishing a metal part on any firearm, the surface must be properly prepared. Here's how I polish gunsmith projects.
We'll start with the material of the part. Steel and stainless steel parts are approached in the same way and we will spend most of this article talking about the methods of bringing them to a degree of shine that will allow us to arrive at the wanted finish. Alloys like those used in the receivers of many shotguns and lightweight handguns cannot be blued so refinishing efforts will be restricted to some sort of alternative finish such as baking lacquers or spray-on epoxies. Most of these receivers are anodized at the factory. If you can locate an anodizer you may be able to have receivers you work on anodized but it is not a finish most of us can apply. Regardless, the preparation of the metal is very similar to the methods used on steel.
Plastic or polymer parts like the frames of many new pistols and a few newer shotguns are a totally different story. While it is sometimes possible to sand or polish out scratches or dings, it is a hand operation only. Unless you have a lot of experience, most power machinery will melt the polymer at the point of contact before you even realize it is happening and make the job much more difficult.
The next consideration is the condition of the surface. This is the biggest variable in determining where to start the refinishing process. You may be faced with anything from a deeply pitted barrel and receiver that looks like the surface of the moon all the way to something that simply has had the finish worn off. We will start with the worst scenario, although you will have to determine at what point you will jump in with your project.
Considering the geometry of the part, flat receivers such as the Winchester 94 and most shotguns take a different approach than round barrels or complex metal parts like trigger guards. Each presents its own problems in polishing and each must be approached differently. Small parts present other problems and each has to be analyzed to determine how they can be polished.
The final issue is the degree of finish. Back when I first decided I'd like to be a gunsmith--along with a number of other foolish notions--there were only two acceptable metal finishes: Nickle and high-luster blue. That was it! Fortunately, times have changed because that high luster blue is difficult to achieve and the slightest error stands out like a dude at an Old West barbecue. Today, we have hunter finishes that are a satin and don't shine and reflect the sun into the animal's eyes, tactical finishes that are flat, a variety of colors, and bead blasted finishes that resemble old time Parkerizing.
Let's start with a badly pitted gun that is in serious need of help. The first step in any refinishing job requires total disassembly of the gun. You want to remove every screw, spring, and pin to examine each of them and decide how much work each will require. Even some of the worst guns I've seen have been pitted deeply on one side but had a pristine bore and internal parts. Unfortunately, there are also guns that have been so abused to make them relics only as they cannot be safely refinished as it would require removing so much metal as to render it unsafe or inoperable. Hang those over the fireplace and forget them.
Once disassembled I recommend stripping all the finish off the gun with a good rust and blue remover. These remove all the old finish and any accumulated rust, including in the holes, under dovetails, and in corners that are really hard to get into. This should leave steel parts a light gray in color. Flat surfaces can now be smoothed out by holding them securely in a padded vise. Use a file by placing it flat on the surface and drawing it toward you. Appropriately enough, this is called draw filing. Like almost everything associated with refinishing, this is a rather slow process and needs to be continued until all traces of all the pits are eliminated.
Round pieces like barrels can also be draw filed to smoothness but require moving the file around the axis of the barrel on each stroke to keep from forming any flats on the barrel. A second option is to use a barrel spinner. These are available from Brownells (#184-020-000AQJ and are used with an abrasive drum or polishing wheel. It is much faster than filing but you must pull the barrel from the receiver and keep the work moving across the abrasive surface to prevent grinding flats on to it.
Be careful around any barrel markings. If they are damaged beyond saving, remove them along with the pits. This should be a last recourse as it makes a much better job leaving them in place and having your finished product retain the manufacturer's name and caliber markings as they were originally. If these can't be saved, remark the caliber for safety's sake using metal stamps before bluing.
With the pits removed, start the polishing process. Production shops normally polish with power-driven polishing wheels, however, unless you have done a lot of polishing I recommend to hand polish using cloth-backed abrasives on a hard backer. Start with a 60 grit and sand along the length of the flat part until all the scratch lines from the draw file are removed. Never sand flat parts just using your fingers as a backer as that is how edges get rounded and screw and pin holes get dished out. I like a hard felt glued to a wood block, or just a wood block with a smooth surface will do.
When moving from the flats to the barrel or any round part, the piece is once again held in a padded vise. Cut your cloth abrasive into strips one to two inches wide and as long as the abrasive sheet. Work the abrasive like you were shining a pair of shoes with a cloth. Sand back and forth and move the abrasive cloth down the barrel until all the scratches from the draw file or sanding drum are removed. This is a slow process. When the top of the barrel is done, rotate it in the vise until the entire barrel has a uniform scratch pattern all the way around and from end to end. Change from 60 to a 90 grit abrasive and repeat. Each time you complete the process with one grit, move to a finer grit and work until all the scratches from the last, coarser grit are polished out. Repeat this process until all the parts have the desired degree of shine. In most cases, 120 grit leaves a nice finish that you can see yourself in. Most folks will stop here.
Small parts are polished the same way but you'll have to find ways to fit into curves, such as the inside of the trigger guard. You may need to use a dowel rod as a backer. I've used Popsicle sticks as backers and used abrasive strips as small as 1/4" wide on tight radii. One thing I'll warn about is making sure there are no scratches left from any of the coarser grits. As soon as the part is blued, any scratch will stick out and announce to the world that you missed a spot.
Depending on the job, you may not have to start with the file or even the 60-grit paper if the job is on a gun with just a worn finish. You may be able to jump in at the 120-grit level or even finer if working on a gun with no problems other than faded or worn bluing.
Now you have the hard and cheap way of polishing a gun. Some of you may be thinking, "No way! Can't you do a good job with power equipment?" Yes, you can but only if (that's a big "if") you are good with it and have the correct wheels and abrasive compounds. For many years, felt wheels have been used in professional shops and have produced beautiful finishes. The work goes much faster and is much less labor intensive. The problem is you must have the money to invest in the tools and spend enough time learning on something of little or no value because the one thing power wheels will do in a big hurry is ruin the work. Spend just a little too much time on one spot and the entire piece has to be brought down to the level of that spot or it will show up as a flaw in the finish. If you mess up with power equipment you could be buying your customer a new gun.
by Paul Mazan
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|Date:||May 1, 2017|
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