Schweinhund

Have you ever got a rim and it wasn't a bad rim but the brake track is looking like nine miles of bad road? I don't mean ground up brake tracks, I'm talking the ones that have blotchy anodizing all the way around and look like crap but are perfectly fine.
I thought up a simple trick. Double stick tape 600 or 800 grit wet/dry sandpaper on a brake pad with it adjusted to cover the whole brake track evenly. Just one pad at a time with it adjusted to lightly ride the rim.
Whether it works or not, I'm going to do it today and post pictures of the fail/success.

unworthy1

worth a try...and might be a bit less messy (or easier to control where the mess goes) if you affixed the wet-dry paper "pads" to a truing stand with a drip tray under the drips (Or under the whole set-up).
Maybe wait for warm weather and do this in a wading pool

merziac

I suspect a more aggressive approach (sand paper) may aggravate the problem.

It will need to take down the high spots with out removing material from the low spots, challenging to do without machining.

I have always thought this a scourge, PITA, lipstick on a pig in a poke after a few hundred miles, look like crap already with a long way to go looking bad.

Schweinhund

Not so good right now. I was trying to do it outside to avoid a mess, but rain and double stick tape is not a workable combination

merziac

As already suggested a controlled setup on a truing stand might be the way to go, power the wheel with a drill and maybe a socket to simulate the drive on a trainer.

Lattz

once I saw on the interweb a guy doing the same in like seconds with a knife sharpening stone, but he said if you walk nearby building demolition sites, a piece of slate is a finer approach (although I guess chance of finding one highly depends on the continent you live on). He just slapped the bike upside down, and revved the wheel and used the stone like the tools when milling. For front the drilling machine is a good suggestion.

krakhaus 

A spot of oven cleaner and a scotch brite pad will make quick work of that problem. Nice and even without a bunch of gouges.

Andy_K 

I like this suggestion. The goal here is to remove the anodizing without removing any of the rim material, right? The 800 grit sandpaper isn't going to take off much metal, but you don't want to re-invent machined sidewalls without the fine control needed to make sure they are evenly machined.

Bianchigirll 

It’s called Patina by the hipsters and it lends character to the bike

Schweinhund

Slate is easy to come by, that's worth a try, wet dry sandpaper doesn't touch hard anodizing so slate is on the trial list.

Schweinhund

Oven cleaner works, but stopping it from getting where you don't want it is a pain.
I've de-anodized then polished quite a bit of aluminum, and oven cleaner really works, but controlling it...

SJX426 

IMHO, any approach is prematurely wearing out the rim. I don't do anything and as stated, it is part of the Patina. There are diminishing opportunities for C&V replacements over time.
Sanding or other abrasive methods reduces the the thickness of the side wall.
Removing anodizing layer removes the harder surface allowing for accelerated wear.

There are no new direct replacements for many rims. It is a consumable part.

P9201318 on Flickr

Schweinhund

After failing miserably, and knowing I can't control lye sufficiently to "bleach" the anodizing in an isolated area, I may have to learn to appreciate what I cannot change...

xiaoman1 

Wabi-Sabi is a term I have used this term in many threads for those that are always seeking perfection......I does not exist and all things will deteriorate with use and time.
I appreciate the service that a thing provides me, imperfection is perfection.

For Bike Friends

JMHO, Ben

smoothness 

i suggest you take a pic of the worn anodizing before you attempt to remedy it. some rims (such as the Mavic Open Pro CD models) have splotchy coatings due to the tension on the rim from the spokes putting tension on the rims. those areas that are lighter are slightly raised compared to the rest of the brake track, causing the hard anodizing/ceramic coating to wear faster on those spots. the photo that SJX426 is a great example of what happens over time.

Schweinhund

That's exactly what I'm looking at

panzerwagon 

This approach requires well trued wheels, otherwise metal will be removed unevenly. Even still, some light-weight rims are so thin, high spoke tension can reveal brake-wear spots adjacent to eyelets; you'll be weakening the areas experiencing the most stresses. In any case, no matter how the sandpaper is applied, rim lifespan will be reduced for purely cosmetic reasons.