Are sugino 75 cranks clearcoated?
 

I am trying to polish my cranks via the process described here. Every time I spray them with oven cleaner, the surface becomes charcoal black and takes forever to clean off. My theory is that there is some sort of clearcoat over the anodizing that is reacting with the oven cleaner.

Is this the case? What can I do about it?

I think they may be. Where me sneakers[I wear skate shoes] run against the crank arm is noticable and took the Sugino logo completely off in under 2 weeks. It definatly looks like a thin clear coat.

mine have clearcoat

What can I do to remove it?

The oven cleaner seems to be working, but it's a major PITA.

Acetone.

just out of curiosity...have you tried hitting it with some smooth wet sanding or the polishing compound?

if they are/were clear anodized you may have already removed it. I have had oven cleaner turn the aluminum a super dark grey color with repeated spraying. I used a super fine grit wet sanding paper to clean it off then the alu polish...came out mirror.

Now if it is clear "coated" ala some paint process...you may need stripper. Bring ones....or fives if you roll thick.

I have tried sanding and polishing, but I think that there is still anodizing, as the surface is now somewhat uneven and still a bit shiny (not dull, as I would expect it to be). When I sand, the paper immediately gets coated with glossy silver particles. I'm guessing that I may just be getting down to the anodizing layer.

I tried the same process with a spare stem, and that just went dull and didn't turn black...

P.S., That's some excellent work, jinx4. Very impressive.