Erik

My precious old Chesini frame is starting to show some rust on the horizontal and vertical chainstay's. I'm a bit worried this will be the end of my frame. The paint in these areas is also damaged quite badly and flakes off very easily. Is there a way to save my frame without stripping the paint entirely? I really don't want to remove the paint because it is what makes the bike so special. I added some pictures for you to see!

Retro Grouch 

If the paint is flaking off easily, I think that it's done.

I don't know about the Netherlands, but in the US there are a few bicycle refinishing specialty firms that can restore your bike's finish, complete with decals, to as-new condition. They do an excellent job, but they don't come cheap.

TallRider

The paint job itself might be done, especially in that area. But it doesn't appear that the rust has much compromised the steel itself in that area.

I suspect you can find specialty bike-paint-refinishing places, or auto-body shops, that can handle this.

Alternately, you might do things yourself. It appears that the rust and flaking are in not-so-visible places, and you could sand down that area (getting rid of rust, and smoothing the merger between bare steel and currently okay paint), hit it with some primer, and then some cover paint whose color is not too different from the current paint job. The area where the stays connect to the bottom bracket is rarely very noticeable.

San Rensho 

Thats just surface rust which from the photos, does not look like it affects the structural integrity at all. I don't think theres any other fix than to sandblast and repaint. It looks like its a bad paint prep job that is making the paint flake off.

HillRider

If the rust is mostly external, your frame is ok and the "damage" is mostly cosmetic. A repaint or cleanup and local touchup will be adequate If the rust has penetrated from the inside of the tubes, the frame is probably due for the discard pile.

Take a sharp nail or similar and poke around the chipped areas. If the metal is sound in those areas, you can safely restore the frame. if you feel soft spots or go through the tube wall, kiss the frame goodby.

enduro

Pull the BB and check the inside of the chainstays for serious rust; a little surface rust isn't serious but now would be a good time to apply a rust preventative.

Michigander

I know it sucks, but my best advise is that the only smart thing to do in the long term is to have it refinished. The cheapest way to go is to find somewhere in your area that does commercial acid dips. That will remove all paint and rust and cost 20 bucks or so. Then you can refinish it youself.

Old Breadbutt

I used to work on a submarine. (I'm not bull****ing)
I had to spend hours chipping away rust and covering the area with a converter.

my point is this, first you'll need to get rid of any loose paint, it can hold moisture and cause new rust. second, you'll need to remove any excess or loose rust. this is often done with a hammer, but in the case of a bicycle frame you may want to opt for something less aggressive like a steel brush. once you have all the loose rust off, you can paint that surface with a special product that converts rust into a paintable surface. (not rust remover, NOT naval jelly)
I think Rust Knock Out is one of these:
https://www.rust007.com/knockoutabout.htm

I can't remember the name, but the product we used turned the rust black. after the rust has been converted you can prime and paint or do whatever you want to restore your bike, but either way, I'd make sure to seal the surface (as best you can) from further moisture (nothing is perfect or will last forever)

ken cummings

The rust treatment advise sounds better than any I can give. For rust prevention there is a company in the San Francisco area that is giving away small promotional cans of a lubricant/rust preventer called Fluid Film. I am trying my can now. If you must remove the paint job there are several bike painting shops that could redo the same exact paint job.

lmzimmer

How old is the bike? Obviously an old friend. Consider giving it a place of honeor-like mounted on your living room wall (Talk with wife first) and inveting in a newer updated ride.

San Rensho 

The rust converter mentioned is phosphoric acid, comes in many flavors. Body shops sell one brand, marine stores have a brand named Osphocote (I believe). Just look for a product whose active ingredient is phosphoric acid.

Phosphoric acid converts iron oxide (rust) into another compound, whose name escapes me at the moment, rendering it rust proof and stopping the cancer of rust. The most likely reason your paint flaked is because a good painter will treat a bare frame with a phospho acid etch before painting. Yours didn't.

Dr.Deltron

ANSWERS; Not really! Buy your beloved bike a new coat! The problem is likely to exist throughout the frame so new paint or powdercoat is your best bet. I could paint it for you, if you want to send it all the way to California!
Check with your local bike shops and see if they know of any bike painters closer to you than I am.
Cheers,
Dr.D.