Protecting Steel Parts From Corrosion by Parkerizing
Parkerizing is a chemical process that creates a corrosion-resistant coating on steel parts. It’s been around since the late 1800s but gained popularity with the formation of the Parker Rust-Proof Phosphating Company of America in 1915. Of course, Harley-Davidson was quick to adopt this process and used it extensively on its early machines and continued to use it to varying degrees through the 1960s. Parts that have been Parkerized are dark gray to almost black, and if you’ve ever looked at an old Harley-Davidson, you’ve probably noticed a lot of fasteners and brackets with a matte gray finish. Nowadays, Parkerizing has been replaced by zinc electroplating, so you just can’t run down to the local hardware store and pick up a Parkerized nut or bolt for your old motorcycle. Luckily, the gun industry still uses it, and you can purchase Parkerizing solution online from companies like Brownells. Then all you need is a couple of stainless steel pots and a two-burner hot plate to start Parkerizing parts in your own garage.
1. Gather all the parts you want to Parkerize. While you can just do a single nut or bolt at a time, you might as well do a whole batch at once.
Tips & Tricks
If you have nuts and washers, thread them onto a piece of wire and then twist the ends of the wire together forming a “hardware necklace.” This makes it easier to pick up the parts with the thick gloves inside the cabinet as well as keeping any of the smaller parts from falling through the grate.
2. Clean all the parts in a blast cabinet to remove any previous finishes, grease, dirt, etc. If you don’t have a blast cabinet, a wire wheel or brush can be substituted.
3. Clean all the parts with lacquer thinner to remove any oils or other chemicals that may remain after blasting. Make sure to do this in a well-ventilated location and to wear the appropriate safety equipment.
4. Set the parts on a clean paper towel to dry.
5. Pour 1 gallon of distilled water into the first stockpot and bring to a boil.
6. Pour 114 ounces of distilled water into the second stockpot and bring to about 140 F, then add 14 ounces of Parkerizing solution. Bring the combined solution to 190-195 F.
Tips & Tricks
Mark the water level in the stockpot containing the Parkerizing solution with a Sharpie. As the water evaporates, add more distilled water to the stockpot to keep the water level constant throughout the process.
7. Pour one gallon of distilled water into a baking pan or other clean container for use as a rinse tank.
8. Suspend your part from a piece of stainless steel wire. The fewer points of contact, the better.
9. Immerse the part into the stockpot filled with boiling distilled water for three to five minutes to preheat the part. This can also be accomplished in an oven set to 212 F.
10. Remove the part from the stockpot filled with distilled water and immerse it in the stockpot, which is filled with Parkerizing solution. Once immersed, the part will bubble, fizz, and begin to darken.
11. When the part stops bubbling (usually between three to 10 minutes depending on its size), remove it from the Parkerizing solution and immerse it in the rinse tank. Lightly scrub the part to make sure all the Parkerizing solution has been removed.
12. Remove the part from the rinse tank and set on clean paper towels to dry. AIM 376
• Blast cabinet or wire wheel/wire brush
• Lacquer thinner
• Chemical gloves
• 3 gallons of distilled water
• 14 ounces of Brownells manganese Parkerizing solution
• Measuring cup
• Two 8-quart stainless steel stockpots
• Two-burner hot plate
• Baking pan or similar open container
• Stainless steel wire
• Paper towels
• Scrub brush