MARK LEE METAL FINISHING FORMULAs
FILING AND POLISHING
The main goal is to polish the metal while preserving the lines of the firearm without rounding off edges and screw holes. Soft buffing wheels can quickly make a mess in the wrong hands. Hand polishing, using files, stones, and laps will produce the highest quality finish.
FILES: For removing pitting and truing up surfaces, files are usually used. Files come in a large range of cuts just like abrasives. Check out www.gesswein.com to see what is available for any of your metal finishing needs.
MOLDMAKER STONES: If you have never used mold polishing stones you will be amazed. I would suggest that you get a moldmaker stone kit from Gesswein so you can try all the different stones and then choose the specific ones that you find the most useful.
The stones come in different hardness and grit sizes. The stones should be used with a stoning oil, WD40, or kerosene if you don’t mind the smell. The stones will conform themselves to the shape you are polishing. With these stones you will be able to easily polish areas that would be otherwise very difficult. Keep the stones separated by grit.
After polishing an area with a stone, wash the part off before moving to the next grit so that you aren’t contaminating the finer stone.
SUPERABRASIVES: Diamond and Boron are super abrasives. These abrasives cut extremely fast and don’t dull like emery, aluminum oxide etc. Diamond and boron can be plated with a coating of nickel onto steel to make honing tools, sharpening stones, and even high speed milling cutters. You can make your own custom hone in any grit from 60 to 50,000. Contact www.salt-superabrasives.com to get specific coating thickness. I use a steel rod plated with 320 grit Boron to hone scope rings after they are mounted to a receiver. This is far superior to sloppy lapping compound and it’s much faster. Super abrasives are available in pastes from Gesswein and are very useful for obtaining a mirror finish.
The inside raceways of a rifle receiver can be polished to a mirror finish after stoning by shaping the end of a hardwood stick, applying a small dot of 1200 grit diamond, followed by 3000 grit on a balsa wood stick. The mirror finish on internal lock parts can also be done this way. It may not be the way Purdey did it in the old days but it might be today. There are also sponge pads coated with diamond that work great for barrel polishing.
SET UP WHEELS: Set up wheels were used by Winchester, Colt, Smith and Wesson etc. As an apprentice for 6 years this is the type of wheel I used. Wheels were made of muslin, felt, wood, or leather. The felt wheels were shaped to fit a particular contour, then a hot hide glue was brushed on and rolled in a tray of emery. We used Turkish emery which became finer as it was used. We used grits from 120-320. Stitched muslin wheels were good for barrels. We glued ½-inch wide muslin wheels together, true with a wheel rake, then coat with glue and roll in emery.
After drying overnight we would break in a new wheel on a scrap of steel. Polishing wheel grease was used during polishing. The wheels would last for weeks of polishing. When they needed to be recoated we used blocks of pumice that we held to the moving wheel to remove grease. Wheels were then reglued and rolled in emery. The wheels could last a lifetime as they were recoated before going through the abrasive coat. A 240 grit Turkish emery on a set up wheel seemed to be the equivalent smoothness of about 400 grit paper. Firearm manufacturers trained new polishers by starting them on easier parts such as barrels and left the receiver flats for the masters. I am not recommending this method as it has a long learning curve but I had to mention it.
CONVOLUTE WHEELS: These modern polishing wheels are the way to go but they are very expensive. The wheels are available in many sizes, hardness and grits. They are made by 3M and Norton.
BELT POLISHING: Belt grinders are a great tool to have in your shop and are invaluable for making short work of many polishing operations. Belts are made in many different grits and backings including some made for buffing. Leather belts are also available.
FINE WIRE WHEELS: Wheels with .005 wire are useful for blending when used with a little oil. This finish is sometimes used as a final operation before hot bluing.
BLASTING: Abrasive blasting can be very helpful for your rust bluing setup. I would recommend using 150-240 grit aluminum oxide or garnet. Set your pressure to about 40 psi. If you can use this blasting cabinet just for bluing I would blast parts after the cleaning operation. This eliminates any cleaner residue and leaves the metal in the perfect condition for the rust bluing process. During the rust bluing operation the oxide coating is getting burnished with either a fine wire wheel or steel wool so the blue black finish is going to have a nice sheen even though it was blasted. Do not use sand or glass beads for blasting as the sand isn’t graded fine enough and the glass beads treat hard steel and soft steel with very different textures.