dougmc

So, I'm fixing up an older bike that's been out in the elements too much.

Most of the frame is fine, but some spots have some rust. I've got some rust remover and auto touch-up paint I'm going to use there.

However, some of the components have lots of rust -- brakes, bolts, etc. What should I do with these? I could use the rust remover and I imagine that'll work, but won't it have lost it's protective covering and rust again pretty quickly? These are things that aren't usually painted.

I might end up replacing all the bolts and such, but it's a pain in the neck to find replacements and I may not bother if I can get the rust off well. But I'd rather it not rust up again just from one day getting caught in the rain, for example.

Some sort of clear covering? Any suggestions?

Grand Bois

Yes, the parts will rust again since they're unprotected. Auto wax helps some.

tpelle

Here's a tip that I ran across on the 'net:

To polish corrosion off of chrome or natural aluminum parts, get some sort of metal polish compound - the stuff I've been using is about the consistency of automobile liquid wax - but use crumpled aluminum foil as your polishing "rag". I'm fixing up an old 10-speed that has the bottom half of the forks chromed. I tried the polishing stuff with just a rag, and with a buffing wheel on a Dremel, and was not getting good results at all. Just for the heck of it I tried the aluminum foil, and the forks look like new! A coat of auto paste wax, and so far they still look good.

Grand Bois

Do a search for oxalic acid.

DannoXYZ 

He's not worried about removing the rust, but what to do to prevent it from coming back. First a little background on removing rust.

While oxalic acid dissolves rust (actually converts it into a water-soluble chelate), it also dissolves bare metal at an equally fast rate. It will also creep across underneath the chrome-plating and remove the good metal underneath, causing the chrome to flake off easier. A much, much better compound to use is Naval Jelly (phosphoric acid). The reaction is similar in forming oxalates, but phosphoric acid eats away bare metal MUCH, MUCH slower than rust. It also leaves a thin coating of iron phosphate on the surface, which protects against further rust & damage (only temporary). With either compound, be careful with the handling as the oxalates formed are reactive with the iron in your blood just like cyanide.

For the OP, he can just touch up the spots that had rust removed with grey-primer. Use a small brush or Q-tip to apply. It blends in fairly well with chrome finish. And on old bikes, it's much, much less noticeable than rust.

Grand Bois

Do a search for oxalic acid. Many people have used it with great success for removing rust from rusty bicycle parts. They even treat frames and forks. You'll probably find pictures, too. You can buy it as a powder on eBay. You can also buy it in the form of deck cleaner. You soak the parts in a weak solution until the rust is gone. Protecting the resulting bare metal is a problem, but I can't see painting each pit in the part with grey primer and a Q-tip as a practical solution.

Bikewer

For surface rust (with no pitting), I always just use the wire-wheel on my Dremel. The wheels are brass or bronze, somewhat softer than steel, and don't do any damage.

Wax or clear-coat will help prevent further rusting, as will being careful not to leave the bike out in the weather which is likely what caused it to begin with.
Sometimes, a search at an auto-parts store will turn up some touch-up paint that matches pretty well.