Crank Polishing

Okay, stop snickering. This time it's literal. Here is what the crankset looked like to begin. The dark spots are places where the original factory coating has flaked off leaving corroded aluminum to absorb dirt and grease and crud. The bubbly looking spot are where the finish has started to lift. I was a little skeptical about how feasible it would be to strip the finish and buff these out so I asked about it on the Classic & Vintage section at Bike Forums and the response included some truly beautiful results. Thus encouraged I went after it.

First step was to remove the old finish. I don't know just what it was or how it was applied. I'm guessing powder coat. It doesn't matter. My favorite paint and finish remover is the aerosol spray "Airplane Finish Stripper" available at all auto parts stores. I haven't found any finish that it doesn't just peel right off. It usually takes two applications. Mostly to cover spots that were missed. Spray on, wait about three minutes, wipe off old paint with a wire brush. Rinse. Repeat.

This scabby looking pair is the result. If this were an anodized finish, that would have to come off also. Since anodizing is an extremely hard aluminum oxide, it's harder than the grit in your sandpaper. Easiest way to remove it is with oven cleaner, the kind with all the warnings about wearing rubber gloves.

Now it's time to do some rough sanding to level this surface and remove the leprous patches. I used a flapper wheel in my drill press for the first pass.

The flapper wheel is about equivalent to a 150 grit I followed with 300 and 600 to get an even dull finish. Not unlike the original factory silver paint

Still not perfect, but so vastly much better that I'm good to go with it. Now some 1000 grit and some time with the buffing wheel.

There are a few spots that could be better. I'll work those down with the 1000 until the scratches are gone and then repolish. From a distance any amount of polishing helps hide the flaws and irregularities. Get up close and the shine only makes them stand out.

That's enough for today, off to go do some paying work.

Thanks for looking in. If you're involved in this sort of madness and have any questions or advice, please feel free to comment.