sambicyclebasement

Everything comes in black now!

I bought a new-in-box black Garbaruk chainring at the bike jumble in September for $40. There are no hills in New York City, so I don’t need my 2x setup anymore, and I don’t want to wear out the big chainring of the set needlessly. My 1x setup works wonderfully and is perfectly geared, but the black chainring on carbon cranks looks incrdibly ugly with the rest of the bike. I don’t have any other cranks with a compatible spider, so I’m stuck with those. My coworkers strip and paint things often, and they inspired me to just de-anodize the chainring to make it silver. I was supposed to do it in the shop, but nobody was around to unlock it for me today. But, the hardware store was open, so I got everything I needed and did it on my fire escape!

My de-anodizing process wasn’t perfect, there are a few little splotches and smudges of the black anodizing still left on the chainring, especially on cnc’d edges and ramps. I think it looks pretty cool with those little remnants on it.

What I used

• Nitrile gloves
• Plastic wrap
• Easy Off oven cleaner
• Brillo pads
• Scotch-brite
• Metal polish
• Warm water
• 2-3 Microfiber rags

De-Anodizing

Aluminum is anodized using electrical currents and chemicals. The item to be annodized is submerged into an acid electrolyte bath with a colored dye. When an electrical current is passed through the tub, the aluminum acts as an anode and pulls the oxygenated dye onto its outer surface. This new surface coating is corrosion resistant and can be made in lots of different colors!

My chainring was anodized black at the factory, and I wanted it to be silver. I could have order a silver one for $150, but doing it at home seemed more fun. The cost of materials was only $30 anyways.

Removing the layer of anodization essentially removes the aluminum’s only protective coating. Raw alumnium will oxidize and degrade on its own over time, so the metal polish is important for maintaining the integrity of the material.

The Process!

• Make sure the item is clean and dry! Make sure you and your item are outside or near a window!!
• I used a piece of carboad as a sort of cutting-board for easy transport and so my chainring didn’t fall through the gaps in my fire escape. Place down a sheet of plastic wrap large enough to wrap the item with. Put your item on the plastic.

• Put your gloves on. I don’t know what is in oven cleaner, but I know it’s super toxic and could possibly. My coworker said its the same substance from the chemical burn scene in fight club, and that vinegar will stop it reacting with your skin. I kept a thing of vinegar nearby just in case.
• Spray liberally with the oven cleaner so that both sides are evenly coated. Wrap the item up in the plastic wrap.

• Let the oven cleaner work for 10-12 minutes, no longer than 15. It may eat into the material if left too long.

• Take out the item and wash it in warm water to stop the reaction. Add soap to your abrasive pad, and scrub off the remaining anodization.

• Dry with a microfiber towel. Apply the metal polish with another microfiber towel, and buff it out with a third microfiber towel.
• Clean and reapply metal polish every 6th months to keep the aluminum safe.

All done!! Go crazy!!