Parkerizing, and how I do it. By Chris Haynes
What is Parkerizing? Parkerizing is a metal finish used on virtually every antique motorcycle ever produced. It is a process that turns bare iron or steel into a finish protected by Zinc or Manganese Phosphatization. The process can be done in many different colors, but the color most often used on motorcycles is dark gray or black. Zinc will give you the dark gray while Manganese will give you a darker, closer to black. Zinc holds up a little better than the manganese though.
Finding which parts should be treated will require you to spend some time with a magnifying glass and factory photos. Parkerizing is a process that can easily be done at home. All parts must be thoroughly cleaned and stripped to bare metal. If you have made any repairs with brass, be aware Parkerizing will not adhere to it.
First thoroughly clean and degrease your parts. Then remove any old Parkerizing Cadmium, or Zinc plating. This is easily done by first carefully washing all areas of the parts in cleaning solvent or carburetor and parts dip. Using a wire brush or wheel will help get stubborn areas clean. Be sure you have removed all grease and dirt from the parts. In a well ventilated area place the cleaned parts in a glass or stainless steel bowl of Muriatic acid. Put the degreased parts into the acid and stand back until it stops its action. Do not breathe the fumes. This usually takes three to five minutes and will remove any old Parkerizing, Cadmium, or Zinc plating. Now rinse the parts in clear 200-degree hot water. The parts should now be clean bare metal, if not continue to clean the parts until they are spotless. Do not touch the clean, bare parts with your bare hands, as the oils on your skin will ruin the process. Clean cotton gloves or a pair of tongs will help here. You can buy Muriatic acid at most hardware stores or swimming pool supply stores. Be sure to stay out of doors when stripping as the acid gives off poisonous gasses when used. Do not touch the acid dipped parts with your bare hands, wear the gloves or use the tongs.
Now that you have thoroughly cleaned and stripped parts, you are ready to Parkerize. You'll need a few easy to come by items. The first of these are heat, as in: easily acquired by turning a knob on the stove. If your significant other doesn't want you to be fouling the air in the home you can always retire to your garage or yard with an electric hotplate. One with two burners work best. You will also need some stainless steel cooking dishes deep enough to cover the parts you will be Parkerizing, preferably one with a cover or a piece of foil etc. to stop the solution from evaporating. Also a 200 degree candy thermometer, a measuring cup with ounces, a pair of tongs, some clean dry towels and a quart of new motor oil and of course the Parkerizing concentrate.
Parkerizing chemicals are available from many sources. eBay or your local gun shop is a good place, or try a chemical supply company. Or you can order the solution from Vernon Owens, 2311 Old Parker Road, Greenville, SC 29690 Phone (803) 246-3836
Once you have collected the required materials, follow the mixing and heating instructions provided with the Parkerizing solution. I use distilled water to mix with the concentrated solution but plain water works fine. Sometimes I have mixed the solution a little stronger and it works faster. Heat one container with water only to 200 degrees. This will be a final rinse and also pre heats the parts before they are placed in to the Parkerizing solution. Heat the mixed solution to one hundred and ninety-five degrees. When the brew is up to temperature I like to pour it through a permanent coffee filter. There are available at your grocery store in the coffee section. This step will remove the crystals that have appeared in the solution. Now place your parts into the solution and cover it. Don't dump a whole load of parts at one time as this will cause the temperature to drop. Using the tongs occasionally turn the parts so the finish will come out even. Don't let the parts stick out of solution or a permanent line will be on the part. Add more mixed solution as necessary to keep parts covered as it evaporates. When the parts are done quickly remove them, hot water rinse them and towel dry them and dunk them into the motor oil that has been heated to the same temperature as the solution. I heat my oil in a small electric frying pan. This will help protect the finish as the oil is absorbed into the pores of the metal that have been opened by the heat. You do not need to leave the parts in the oil for long. A minute will be plenty of time. This entire process takes about an hour. If you are Parkerizing parts that will be painted, don't oil them.
Parkerizing the inside of fuel and oil tanks, as the factory did, to prevent rust is a good idea. Clean and strip the inside and outside of the tanks by sandblasting. Then plugging the fuel line holes and the pouring in a pack of BB’s or steel shot. Then add muriatic acid and slosh it and the BB’s around inside the tank until clean. Thoroughly rinse the inside of the tank with hot water. If you don't have a container large enough to hold the tank, plug all holes in your tank and pour the preheated solution into your clean, rinsed, stripped, preheated tank. Make sure the tanks is full. Heat it to temperature in your oven for twenty minutes. When finished thoroughly rinse the Parkerized tank.
Save your Parkerizing solution as it can be reused.
Your parts are now ready to correctly complete that loving restoration.
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