Like "frosting the pastry," "wind surfing on Mt. Baldy," or "shaking hands with Abraham Lincoln," "polishing my crank" may sound dirty but it really isn't.
In this case, it was the result of planning a parts bin build for my recently acquired Cannondale, but then seeing how nice the paint was cleaning up and deciding that I needed to build it up with nicer looking parts. I had considered rebuilding it with the original parts, but when I started stripping it down I saw that they were too heavy and in too poor shape to even give a fair impression for a few test rides to see how I like the bike. So I started going through the parts bin to see what I could use. I've got an FSA Gossamer triple crankset that I've had for over ten years and at this point use almost exclusively for bin builds (more on that later). It's so chunky and badly scuffed up that I never want to leave it on a bike that I like any more, but it's perfectly functional, so I keep it around for quick builds of newly acquired frames.
I thought I'd do that again with the Cannondale, but as I polished up the beautiful, sparkly metallic blue paint, I began to fall in love. And so I started reevaluating what parts I had on hand. I've got some really nice 10-speed Shimano derailleurs and a set of SL-7900 indexed Dura-Ace downtube shifters, but I had no suitable crankset. Then I thought, maybe now is the time to take a deeper dive into the wonderful world of parts polishing. I've got some Mother's aluminum polish, and I've used it to very good effect on parts that were in basically good shape but had lost their luster. The Gossamer crank, unfortunately, started life as an anodized part and more than half of it still was anodized. So, recalling a few instructional threads I'd read here, I decided to pick up some oven cleaner and see how well the trick of removing anodizing works. I figured this crank couldn't get much uglier, so there wasn't much to lose.
It turns out, the trick works really well.
Stepping through this to show my progress, here's the crank with chainrings removed, showing its full patina.
I had tried sanding the anodizing off of the NDS crank arm, but the impracticality of that asserted itself quickly. For the drive side, I used nothing but Heavy Duty Easy Off and a wet sponge to get this result.
Next, I spent some time wet sanding, using 400, 600, 1000, 1200, 1500, and 2000 grit sandpaper, to get to this point:
Finally, a very little bit of work with Mother's Mag and Aluminum polish yielded a very shiny surface, shown here with the merely de-anodized NDS arm for contrast.
Another half hour or so going through the same process with the NDS arm, and I had a matched set.
And, of course, the thing that made this project worth undertaking was that I had some very lightly used chainrings to put on it.
Those with good eyes will see that I left a lot of small scratches. I hear you can work those out with more sanding, but I didn't want to do that much work. It also looks like I didn't sand the NDS arm down quite as well as I did the drive side. I'm OK with that too. I imagine after a few rides even the most perfectly polished part will start to look like what I've got here. The key for me was to get a crank looking nice enough to not detract from a frame that was starting to look nice. The frame isn't perfect either, so this is a good match. I also think the oversized tubes on the Cannondale will be more forgiving to the chunkiness of this crank than a steel frame would be.
Finally, I'd like to explain why I thought this was worth sharing. There have been other threads posted by people more skilled and more patient than myself. They've also left better instructions for how to do this yourself. Apart from being pleased with my own result and wanting to share, I thought it would be worthwhile showing others who, like myself, are impatient and unskilled at this sort of thing that they can, nevertheless, get some pleasing results.