Much of the cost of refinishing a firearm is the labor cost of preparing the metal for the new finish. The Hobby Gunsmith can save quite a lot of money by doing most of the time consuming work before taking it to the commercial shop. We have regularly cut plating costs in half because the work was ready for final buffing and plating. This article is intended to take the reader from a damaged gun to one that is ready for a fine finish using either the bluing techniques shown in other articles, or to demonstrate how to prepare the gun for a professional finisher. Two project guns will be used to illustrate these methods: The Colt Dragoon conversion and the Remington Kirst conversion.
Working on a metal firearm is similar to doing woodwork, but slower. Some of the tools are different, but others are the same. Instead of using a wood rasp, putty, and sandpaper, we will be using files, welding or brazing, and emery cloth. Fine sandpaper will be used in the final finishing of the product as we prepare it for the finish.
If the gun still has the factory bluing, it can be removed either by brushing on some Navel Jelly rust remover that is available at most hardware stores. Just brush the Navel Jelly on the part and wait a few minutes. You should see the blue finish dissolving within a few minutes. Rinse the part under hot water to remove the jelly and then carefully dry the steel to prevent rusting.
We begin by carefully examining the parts to be repaired and finished. We start with the Dragoon project gun that is badly flawed by damage on the right side of the barrel frame. This damage can be seen in Figure 1 below and is too deep to file or sand out. The proper way to repair this damages is to take it to a competent welder and have the damage filled with welding rod of the same alloy as the frame of the gun. A competent welder should easily build up the material, which would allow the excess material to be filed down to the contours of the frame. If the alloys are close and the welder does a good job, it should even be possible to blue the gun with very little evidence of the damage that has been repaired.
I am not a competent welder so I attempted to fill the crack by using brazing rod. The brazing material allows me to illustrate how to fill the void while making it easier for me to machine out the filler to cut a trough to help fit the ejector housing. Any minor problems will be filled with copper plating before applying the nickel plate intended as the final finish for this gun.
After filling the void with brazing material and allowing it to cool, I began filing it with a rough file. Long and careful strokes parallel to the surface of the gun frame assure the material will blend with the surface of the gun. The surface of the material becomes flattened under the file and I switched to a fine file as the surface of the patch began to approach the surface of the frame. The fine file was used to file the entire surface of the frame to properly blend the patch with the frame.
I sanded the patch with fine emery cloth and a backing plate to keep the emery cloth flat. Figure 2 shows the materials used to remove the rough marks left by the file. This barrel and frame is destined to be nickel plated so I have started the process of building up some flaws using a copper coat in much the same way we might use a filler when doing woodworking. The copper coat allows me to fill the metal with copper and sand down the excess copper from the high areas. This technique should be covered in a future article on electroplating in the home shop. I brushed unscented mineral spirits to keep the abrasive sharp and to prevent clogging. Figure 3 shows the frame after filing and sanding. Please note that the pits and voids were caused by my poor brazing technique and not by any flaws in this process. The patch now blends nicely with the surface of the frame.
Final finishing work takes a lot of time and patience. It is necessary to do a lot of sanding if the Hobby Gunsmith wants to use a rust bluing process on the metal of the gun or to send it out for a commercial refinishing job. Let's begin by covering the process. We will be using the 58 Remington IKirst conversion project to illustrate the final finishing process.
We begin by carefully inspecting the frame of the gun. The Remington project gun has flat sides on both the lower portion of the frame and above the cylinder area. We will sand these areas using the emery cloth and an eraser as a backing block. Any reasonably hard and flat surface will work as the purpose is to not use our fingers as they will create minor waves in the surface of the metal. Using a stiff and flat surface will help prevent these waves and make the job much more professional looking. The rest of the frame has curved surfaces that can be sanded using the eraser while the recoil shield will require us to use our fingers as it is very convex. I usually avoid working on the inside of the frame, but those areas can be cleaned up by wrapping emery cloth around a file and working on the internal surfaces. The Remington has a very concave part where we cut away a loading port in the recoil shield. That loading port will be sanded with the emery cloth wrapped around something like a spent cartridge or wooden dowel. We would wrap a strip of emery cloth around the barrel and work it like a shoe shine buffer if we were sanding a round barrel.
After determining how we will sand the surfaces, we start with fine emery cloth that resembles 220 grit sandpaper. Emery cloth is on a cloth backing instead of paper and holds up much better as it's intended to be used for working with metal. Use the pink eraser as a sanding block and try to use the whole flat surface and not the pointed ends. Using the entire flat surface will reduce the number of ripples sanded into the surface of the steel. Liberally brush unscented mineral spirits onto the emery cloth and the part in order to float away the steel that has been sanded from the surface of the metal you are sanding. This will also keep the emery cloth clean and cutting well. Use a wood dowel for concave surfaces and your fingers on the convex recoil shield. When sanding convex surfaces like the recoil shield, I find it helpful to keep the strokes more circular to prevent any flat spots. The tapered tips of the pink eraser sanding block can be used on slightly curved surfaces as it will bend to conform to those shapes. This is especially helpful for sanding the back strap of the gun.
When you are satisfied that all metal flaws have been taken out by the emery cloth, we change to 400 grit wet or dry sandpaper or extra fine emery cloth if its available. Continue using the mineral spirits to keep the metal from clogging the grit of the paper. Some people like to coat the steel with Dykum metal dye when changing paper grits because the Dykum will fill the scratches left by the previous grit and allow the larger scratches to stand out better until they have been removed by the finer paper.
When you are satisfied that you have removed the larger scratches from the metal, you may proceed to a finer cloth for hot caustic bluing or plating. We usually use 600 grit paper to polish out the scratches left by the 400 grit paper. This brings the metal to a very good shine. The next step is to advance on to 1,500 grit paper and really polish that metal until it is almost like a mirror. At this point the gun can be sent to the refinisher and you have done much of the expensive preparation work. Figure 4 shows the Remington frame after being sanded down and is ready for the copper coat that will fill the remaining scratches and then be buffed down.
One thing to be careful of is to not round the sharp edges. This is the reason for using the eraser with a small sanding block. It is very important to not let the paper wrap around sharp edges because they will wear down first and leave you with joints that no longer look as good as they did before you started the project.
I have intentionally avoided mentioning the use of buffing wheels. A buffing wheel can be used to remove the final scratches left by the sandpaper. Using an emery buffing compound, the wheel can be used to remove some rather large scratches, but there is a price to pay for this power assistance: The buffing wheel may turn a flat surface into a wavy one. I prefer to avoid the buffing wheel unless there is an absolute need.
One excellent use for the buffing wheel is to remove the final sanding scratches in curved areas where the buffing action will not make a noticeable difference. This can be done using emery buffing compound with a firm wheel. Another excellent use of the buffing wheel is to use a soft wheel with rouge compound for a final finish. Figure 5 illustrates the same Remington frame after I plated it with copper and gently buffed it with a soft wheel. Electroplating will be covered in a future article.
With a lot of practice and patience any Hobby Gunsmith should have no trouble creating the foundation for an excellent finish on a gun that is being repaired, restored, or modified. I look forward to seeing some of these creations and extend an offer for readers of the Hobby Gunsmith to send me digital photos of your gun work and I will publish them in a section on our reader's own Hobby Gunsmith work.