Anodizing: Give Alloy Parts a Color Bath

Go all the way on your custom by having your aluminum parts anodized

Anodizing aluminum parts for custom look
You can give your forks and other aluminum parts an outrageous look by anodizing the parts.Photography by Dean Groover

You have a vision of a full-on custom bike. You've bought the billet, applied the chrome, lowered the suspension and planned out the colors, but somehow you know something is missing. Top-notch builders leave artistic touches on almost every piece of their project bikes. Unfortunately, whole sections of your bike will be relatively stock unless you can come up with some ideas. What to do? Try having your aluminum parts anodized.

An electroplating process, anodizing bonds aluminum oxide to aluminum parts. While anodizing may sound similar to chroming, it’s really quite different. Chroming gets different metals to adhere to the surface of a metal. Anodizing not only bonds aluminum oxide to the aluminum part’s surface but also allows the aluminum oxide to actually penetrate the surface of the part. The resulting coating covers the part to a thickness of 0.4- to 0.6mm and actually seals and protects aluminum from corroding. Unlike chroming, anodizing has a virtually unlimited color palate available. However, anodizing can only be performed on aluminum.

When Race Tech receives a part for anodizing, it's disassembled (if necessary) and cleaned of any oil residues. Next, the part is etched in a sulfuric acid bath to open the surface of the aluminum, clear pores of contaminants and assist the penetration of the aluminum oxide. If a light, cosmetic color is being applied to a part, the actual anodizing takes place when the part is electrified and placed in another sulfuric acid bath for 20 to 30 minutes. Parts that require the extra durability of hard-anodizing get zapped for a total of 50 to 90 minutes. Hard-anodized parts exhibit extreme corrosion- and abrasion-resistance comparable to nitrated steel, the metal used in most files. Many dirt bike forks and Harley drive pulleys have a hard-anodized surface.

Once the anodizing is complete, the part is soaked in a dye bath for the color application. The longer the part soaks in the dye, the deeper and darker the color becomes. Our Valkyrie fork spent approximately five minutes in the violet dye tank. Although anodizers have an extremely varied color palate (any color except white), both the painters and anodizers we talked to said that the best that anodizers can do is get close to matching a color. If you've already had your bike painted, the anodized part won't be far off, but the best way to have an integrated look to your color is to decide on the anodized color first and take a sample to your painter to match exactly. A final bath of nickel acetate sealer reacts with the aluminum oxide to close the pores and add corrosion resistance.

Anodized parts don’t need to be treated differently than other parts on your bike. Aluminum oxide is hard enough to be used on grinders and course-grit sandpaper. Still, scratches will show through the color so careful reassembly is required. Wash and wax as usual and your stylin’ anodized parts will last for a long time.