Can anyone tell me the best way to paint a bike frame. Can I just sand down the old paint and paint over top of it or do I need to strip it down to the bare metal. I am not keeping the bike and trying to keep my cost as low as I can as I give these bikes away.

In most cases, the old paint makes a better primer for repainting than bare metal. If this were a high end bike going to bare metal is the way to go, but for your purposes, just clean it up, and smoothout out the scratches and chips, and paint over it.

Many co-ops do pretty well this way using rattle can spray paint.

Sand it smooth, leaving the old paint on, and paint away. Make sure you have good ventilation or you will wind up aiming for the frame in the middle as I did when painting an old frame a long time ago...quite the buzz but the after buzz headache was awful...

Don't. It's a bastard of a job.

Either live with the current paintjob, or pay someone to either powdercoat it or give it a proper hardcore paintjob, that's my 2c. Anything you do with a rattlecan will suck by comparison, despite putting in a ridiculous amount of effort preparing it.

Although if it's ally, you could just strip it and give it a brushed finish with some scotchbrite, like mine...

I've done several using rattlecans from the hardware store. My paint jobs don't scream "home paint job" but they don't rival a factory paint job either. The biggest advantage to me is the satisfaction of doing it myself. Once you get the system figured out the cost is reasonable too since I don't charge myself labor.

I can't say how strongly I disagree with the posters who recommended scuffing and painting over the old paint. Every time that I tried doing that the result was the new paint quickly chipping off. I strip off all of the old paint using a chemical stripper, prime and paint. My paint jobs don't chip.

Some people have repainted frames with a brush. If you use a really high quality brush, you might get a decent result.

Well I have a friend that has a body shop and he said that he would sand and paint it free of charge. But I get a few here and there that need the frames painting and I don't want to feel like I owe him something for doing it for me. This is why I am thinking about doing it myself. Plus the fact that I give these bikes away so I need to keep my cost low and don't want to get into paying to have it done.

The factory paint job on my '99 carbon Trek was terrible. I've had it repainted twice on warranty and both times it peeled again. I put it down to poor prep. I've done quite a bit of high-tech painting, so this time I'm doing it myself, frame and fork. I intend to carefully sand off all the old paint, by hand, mostly with #220 paper. In the process, I'll lightly scuff the frame. I'll repaint with Awlgrip linear polyurethane. I'll prime with their 545 epoxy primer, sand with #220, then shoot the topcoat with a HLVP gun, 3 coats, wet on wet. No logos this time. I'll mask off the serial number. Can't decide what to do with the head badge. It's glued on, so I'll try to gently heatgun it off, then glue it back on. I don't want to clearcoat the frame because I want to seal the aluminum cable stops against corrosion with the 545 primer.

Thanks for the information, from everyone. I've decided to take it and have my friend do it. Then I'll deal with the next bike frame when it comes time. Heck if I have to buy him a bottle. so be it.

Brush job:

The bike looks great. What type of paint did you use.

Thanks for the compliment!

I used Rustoleum gloss white thinned 15% with mineral spirits. Just as FBinNY mentioned, the old paint makes the best primer; the sanding and prep just makes sure the old paint edges at nicks & bare spots don't have a hard, well defined edge. There are about eight coats on it, with light sanding between. The last three coats were applied after no sanding, just a wipe down with mineral spirits before paint. The bike was originally black, so you may need less coats on a different base/final color combo.

The unexpected plusses were how little paint it took, and how well it takes to touch-ups after nicks, etc. from use

I agree. When I rebuilt an old mountain bike a couple of years ago, I repainted the frame myself using rattle cans. It came out great and it has held up well (as far as I know, anyway...I gave the bike to my brother and he hasn't called me complaining about anything!).