Refinish Crankset
 

Hey Guys!
I bought a used bike on craigslist and in the process of cleaning it up. Do these cranks look like they have been spray painted? Would I be able to sand it out and polish it by hand you think, I don't have a shop or anything to use tools.
Do you think it would be easier to sand, then use some caliper paint that I've read works pretty well on cranks?

http://bikeforums.net/attachment.php...hmentid=264074

Definitely appreciate any input / help,
Thanks!!

They look either anodised, or they have clear coat.

Do you have the little tool to hold the back of the chainring bolts? That might be a dealbreaker; sometimes you just can't get the rings off without one.

And what about a crank puller?

I wouldn't paint them, I'd go raw, since paint and even anodising tend to get polished off just above the pedal...

I wouldn't sand them either. If they're painted, I'd use paint stripper and give em a brushed finish with Scotchbrite or a plastic kitchen scourer.

Staying in the kitchen, if it's anodising, I hear oven cleaner gets it off... dunno what kind of state it leaves the surface in though.

Thanks Kimmo, I don't think I have that little tool unfortunately,
Also it is a 1994 Cannondale, any way to see if it was anodized or not? Or maybe they aren't the original crankset.
I'll have to investigate further I think.

I think that anything you do to the chainwheels besides clean them up will end up looking worse than by leaving them alone. The farthest I'd go is to pull the cranks, remove the chainwheels (the Shimano TL-FC21 for holding the bolts can be had for about $7.00 and is the only one worth having IMO) and polish the cranks. Anything you try to put on the chainwheels or cranks will wear off or chip in short order and look like hell. Better some honest wear than a lousy looking coverup.

Yeah, anodising is what's happened to the top layer of metal. You can't scratch it off. If it's clearcoat, you should be able to find an area where it's chipped off; you'll see the thin edge of the layer and be able to feel it with your fingernail.

You can give it a go without the tool; you can usually get the chainrings off okay without it. And you can almost always get the bolts tight enough without it. Otherwise, it's like a $5 tool.

Pretty sure OP was just referring to the crank arms, at least I hope so.

True, that. But IMO brushed raw looks better than a shagged finish. Of course, the bit near the pedal will be polished shiny afer a bit, but the sweet thing about a brushed finish is it's a piece of piss to restore.

Except if corrosion sets in... disregard all this if you live anywhere particularly salty.

How badly do you hate them the way they are?

As I see it you have 3 choices:
1. Leave them the way they are.
2. Replace the crankset with something nicer.
3. Refinish the ones that you have.

I've done all three at various times. Usually, even if I hate them, I leave them alone until I get bored. Then I'll try refinishing them. The replacement option is always open if the refinishing doesn't come out satisfactory.

Aluminum isn't the easiest thing to get good painting results. Somebody once advised me to etch aluminum prior to painting by wipeing it with vinegar. I did that before I primed and painted the crankset on my beater bike and, so far, the paint hasn't chipped, flaked or rubbed off.

I was hoping to clean up both the arms and the chainset ( wheels )

Any thoughts on using oven cleaner to take the anodize off and then polish the crap out of them? You think I could get them to look shiny?! :)

I just sent in the bike to get powder coated. So I've taken the time to get everything off the bike and put new stuff on (tape, seat, wheels). I've got 2 weeks to kill before the frame gets back, so I figure if I'm going to clean or replace every other part might as well work on the crankset.
Buying new could be an option, but it doesn't look like these are in that bad of shape, any thoughts?

Thanks!

I believe the cranks are these:
http://velobase.com/ViewComponent.as...40768&Enum=115

Would I be able to buy new without changing any of the other components?

That makes it easy.

Suppose you decide to buy a new crankset. What are you going to do with the old one? If you think it looks bad, you probably won't get diddly by selling it. Assuming that's the case, what do you have to lose by refinishing it? That's what I would do.

Bottom bracket's a crap shoot.

I'd try to install your new crankset on the bottom bracket that I had and then check out the chain line. Knowing how far in or out you need to move the crank and knowing the spindle length of the BB that you have, you can make an educated guess about the BB spindle length that you need for the new crank.

Sometimes the BB that you have will work and you don't have to get a different one.

Most oven cleaners contain caustic soda (sodium hydroxide) which will indeed remove anodizing but doesn't know where to stop. So, if you use it, use it sparingly and wash it off quickly and thoroughly. Don't ever consider soaking the crank in it.

You might consider a shop that does anodizing and see what it would cost to have then "dipped".
IF they are doing a "batch", they may toss it in for a nominal fee.

Trying a "brush on - rinse off" method would probably give poor results, since each area will have a different amount of time the chemicals work on them.
I've anodized small parts, where I could hold the chemical solutions in a relatively small beaker.
A crank would require a much larger "tank", and then you have the large quantity of "solution" to dispose of. That's just not practical for home use.

I have used EZ Off oven cleaner on Shimano cranks with good results. I put the cranks in a plastic dishpan, sprayed them and scrubbed a little with a toothbrush, then rinsed. It took awhile, a couple of applications. The cranks turn a nasty gray/black but that comes off easily with metal polish. The cranks ended up nice and shiny. Use regular EZ Off, not the odorless stuff.

READ THE FINE PRINT on your oven cleaner. It is ammonia based, and ammonia and aluminum create dangerous gases! What alloy do you think your cranks are mostly made of, hint, a magnet doesn't stick to it!!

I don't know about ammonia, but I do use it outside. Whatever it is, I doubt it would be healthy to eat, drink or breathe it.

Yup. Oven cleaner is nasty stuff, but it will take care of the anodizing. How shiny the parts get after the anodizing is off is entirely dependent on how much effort you put into the process. N.b. having a bench mounted buffing wheel and a variety of grades of polishing compound will make this task much easier.

Also, once the anodizing is gone and the surface polished, it will tarnish rapidly with any exposure, particularly to water. Plan on frequent use of Flitz or similar polish, use a good coat of car wax or clear coat the parts.

Unless you want to make em lighter ;)

Actually, that's not a crazy idea; you can 'mask off' mating surfaces with grease or something, and it etches away pretty uniformly. I've heard of this method being used to make a tube's walls thinner.

Which is why I wouldn't consider polishing a raw part; the brushed finish looks a hell of a lot better over time.