Restoring a Classic MTB Part 02: Tutorial – How to Remove Anodizing and Polish Bicycle Components the Easy Way
Expand

Radar

Restoring a Classic MTB Part 02: Tutorial – How to Remove Anodizing and Polish Bicycle Components the Easy Way

Over the next few weeks, I’ll be working on my Yo Eddy! restoration project I began last year. If you recall, I bought an early Yo Eddy! frame from my friend Martin at Second Spin Cycles and sent it off to Rick at D&D Cycles for a new paint job and a few minor repairs. Well, the frame is back in my hands, so it’s time to get crackin’ on this restoration project.

My vision for the build includes polishing a Syncros 29.4⌀ seatpost, as this build kit will have a mix of black and silver components. Most of these seat posts are pretty faded and scratched, so I thought polishing one up would be nice.

Back in 2009, I made a post on this website about polishing vintage seat posts. At the time, I was restoring various Merckx frames and had scored a few unique seat posts. But what if your seatpost, or other bike components, has a colored anodizing finish you’re just not into? Well, read on below for the full tutorial.

Anodizing 101

What is anodizing? In short, anodizing is simply oxidation. Yet the process of anodizing is more complicated than exposing raw aluminum to the elements for years. It combines electrical currents with chemicals. This electrochemical process converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum benefits the most from this anodic oxide finish as it protects the integrity of the metal. Titanium anodizing is more of a decorative treatment.

This anodic oxide happens when you immerse the aluminum material into an acid electrolyte bath with a colored dye. An electrical current is then passed through this bath via a cathode mounted inside the anodizing tank. During this process, the aluminum acts as an anode so that oxygen ions are released from the electrolyte to combine with the aluminum atoms at the surface of the part being anodized.

Vintage Components

Back in the 1990s, with the integration of CNC mills, or computer numeric controlled, the world of boutique, cottage industry component manufacturers exploded. Ringlé, Paul Component, Kooka, and more emerged from small shops nationwide. When the aluminum chips were done flying from the routers, off these parts went to get bright colors and patterns applied.

The problem is that it was over thirty years ago, and anodizing will fade with UV exposure. Suddenly that red hub is a light pink or your black post is riddled with scratches and looks more like purple. For some restorations, this is ok but others might demand a new lease on life for those components.

Keep in mind, even if your parts are faded, the anodic oxidation remains and are still coated with a protective layer of oxidation. But be sure to keep your posts greased in your frames due to galvanic corrosion that sweat can exacerbate.

Aluminum Grades

Various grades of aluminum will corrode on their own, degrading the material and, thus, its integrity. Some will corrode faster than others, so anodizing can delay this degradation. For example, 7075 T6 has a low elongation percentage – or the point it can be stretched to failure – and is highly corrosion-resistant combined with a generally acceptable strength profile. For this reason, many bicycle components are made from 7075-0, just like this Syncros post. However, it is still coated with anodizing to protect it from the elements. So, full caveat, removing anodizing can weaken it in the long run.

What You Need

You remove microns of material by removing anodizing, and there are a few ways to do this. My preferred method is with oven cleaner, which is very toxic, but when you’re stripping a component like a seatpost, sanding the anodizing off will reduce the diameter of the post, and we don’t want that. Here’s a list of supplies you’ll need to do this minimally-invasive procedure:

  • Oven cleaner
  • Plastic sheet
  • Latex gloves
  • 800 grit sandpaper
  • Scotchbrite pads
  • Mothers Mag polish
  • Soft, microfiber rages
  • Tub of warm, soapy water

Process

Do this in a well-ventilated area, and please dispose of your chemicals correctly. Don’t go dumping this down the drain or in your flower bed.

First, clean your components. Remove any chunks of grime, grease, oil, etc. Lay the plastic sheet down and place the components in the middle of the sheet. Now, many vintage components, like seat posts, use a bonding agent to attach the head of the post to the shaft. For this reason, I only spray down the shaft of the post, not the head, hoping not to affect the bonding agent.

Open the can of oven cleaner and align the nozzle with the dot on the lip of the can. This places the spray nozzle in line with the hose inside the can and ensures a steady stream. Liberally spray the component with oven cleaner. You don’t have to go overboard here but get it nice and coated. Then, wrap the part up in the plastic and let it sit for twelve minutes.

Come back and check on the process. The anodizing should be bubbling off. Since you don’t want the oven cleaner to eat away at the aluminum, I wouldn’t let it soak for longer than fifteen minutes.

Remove the component. Wash it in the tub of warm, soapy water to neutralize the cleaner. Then, add some soap to the Scotchbrite pad and scrub the remaining anodizing off. Remember that aluminum has a “grain” and you want to scrub with the grain. If you have pesky spots, hit them with wet 800-grit sandpaper. Remember not to sand down the area of your seatpost where the clamp will be. If there are big scratches, you can hit those with 100-grit sandpaper and work up to 800-grit before polishing it off.

Dry everything off with a microfiber towel. Take a finger-scoop of Mothers and spread it around the post. Then use a clean microfiber towel and polish the post from top to bottom. If it turns grey, then it’s activating. Move to a clean part of the rag and wipe it down.

Final Product

This takes about a half hour from start to end, leaving you with a bright and shiny component. Now, if you live in a humid environment or ride in the rain a lot, you’ll want to clean and add more Mothers to this post every six months to help protect the aluminum from the elements.

This procedure can be done with stems, handlebars, crankarms, seat posts, and hubs. Remember, even if a component is NOS or new-old-stock, it will still have a clear anodizing coating you’ll have to remove before polishing, but I wouldn’t polish NOS parts personally.

Got questions? Drop them in the comments.