Rust Treatment



doctorold

Member
Dec 14, 2010
345
16
18
North Carolina


Ok folks. As you can see in the pic, I have rust coming through on my chain stay. It has already come through on this cable guide and I have chipped off the paint and sanded it a bit to get the rust off and get to bare metal. But my question is: How would you take care of this and not make it look like a mess (even though it already is)?
 
Removing the rust should not be a problem... After that you can paint it with a protective cover. But plastering it and matching the color... might not be as easy... There is also the frame strength issue. Bike frames are allready too thin walled to begin with and the bike frame might break or something...
 
I cleaned up a few rust spots last season using a wire brush attachment on a dremel and then masked off the area and used some spray paint with a closely matched color. After the paint cured I used some clear coat to finish it off. The results cosmetically were good, the areas affected were none too obvious anayway. However, the rust is coming through again this year.
 
Hard to say without further inspection, but I suspect it is "surface rust" and not rust through from the inside of the tubing. If it is rust thorough, you have a much bigger problem.

More than likely a crack developed in the paint around the cable guide brazing, allowing water and air to penetrate under the paint and oxidize. The oxidation has spread under the paint. You're on the right track - have to get down to bare metal and remove the oxidation, then seal it/repaint. What are your painting skills, what paint equipment do you have access to, and how seamless do you want the repair to be?

A Dremel tool would be a big help in preparing the surface, but you can do it by hand with a lot more elbow grease. Some stripper, wire brush (or brush tool for Dremel), varying grit sand paper or grit wheels, steel wool, masking tape, and maybe some muriatic acid. Spray cans of metal primer and some white acrylic enamel and clear coat will patch up the spot after you get the oxidation cleaned up; however, unless you have really good paint skills (and especially with a spray can) the repair will probably be visible. Unless you get ALL of the oxidation and completely seal the area, it will return again in the future.

The alternative is a professional painter and/or a local shop that has a bead blaster to prep the surface. Depends on the value of the frame and how much you want to spend.
 
Thanks for the input so far. It's a Reynolds 631 frame so I really want to keep it as healthy as possible. I am inclined to do my best rust removal with a small wire brush and sandpaper. Then do a tricky tape job to make a semicircle area above the chain guide. I would then use some spray primer and then spray paint. It will show, no doubt. But it will be a far sight better than the rust spreading or even eating through the chainstay. Seems like a lot of work for a small area but this could get ugly if I don't do something now.
 
Originally Posted by doctorold . Seems like a lot of work for a small area but this could get ugly if I don't do something now.
No - right approach. Check all braze points while you're at it. Good luck!
 
All the braze ons are in good shape except this one. I'm sure this is caused by small chip, crack in the paint and sweat pouring off me in the summer time. I just hate to have this much rust already in a 2011 model bike.
 
doctorold said:
All the braze ons are in good shape except this one.  I'm sure this is caused by small chip, crack in the paint and sweat pouring off me in the summer time.  I just hate to have this much rust already in a 2011 model bike.
What bike is it?
 
Originally Posted by doctorold .



Ok folks. As you can see in the pic, I have rust coming through on my chain stay. It has already come through on this cable guide and I have chipped off the paint and sanded it a bit to get the rust off and get to bare metal. But my question is: How would you take care of this and not make it look like a mess (even though it already is)?
Presuming the rusting braze-on is on the custom frame which you had made recently, I recommend that at the end of the season (OR, next week! You can ride your old bike in the interim ...) that you have your frame builder remove the cable guide ... bolster the stay ... and, braze a new cable guide atop the bolster ...

  • AFTER that, be sure to rinse your bike off after EVERY ride!
  • some people use "Pledge" (or, equivalent) furniture wax on their frames ... THAT is probably a good idea which you may want to pursue in the future

Your frame builder can have his painter re-paint the stay ...

Expect to pay $100 +/-.
 
Originally Posted by doctorold .

Custom? Recently? This is the third riding season for this bike. It's a Bianchi Vigorelli.
My bad ...
  • I was thinking of someone else & his bikes ...
  • often times one nom de plume is like many others ...
Well, IMO, the remedy is the same ... you probably just won't have to pony up as much as much as if the bike is sent off to a custom frame builder who would subsequently be sending the frame off to a custom frame painter. Alternatively, if you don't want to go the fore mentioned route-or-something-similarly-aggressive (as necessitated due to the belated attention to the rust in a potentially critical location), then I would guess that you will eventually be SOL. Well, now you hopefully know that "Ridden hard & put away wet ..." can be as bad for bicycles as it is for horses. BTW. 3 years IS comparatively "recent" to me since my reckoning of time is sometimes in arc seconds of the Precessional Cycle ...
 
Originally Posted by doctorold .

Custom? Recently? This is the third riding season for this bike. It's a Bianchi Vigorelli.
My guess is that the rust may have been caused by moisture trapped under the paint. Perhaps some solvent was used to clean the frame after welding which left moisture behind, or some other contamination wasn't cleaned off before priming. Believe the challenge you have is to eliminate all the rust prior to respraying. If any trace of rust is left under the primer, it will come back in time...at least that's been my experience. Products like "naval jelly" can be used to remove the rust prior to cleaning and priming the surface. I've used the stuff on old rusty garden furniture prior to repainting, but don't know how it would work on the 631 tubing.

Maybe Bianchi could offer you some advice. If your frame has a lifetime warranty against manufacturing defects, I'd ask them if the rust was a covered defect. I had a Raleigh Competition frame bought new circa 1992 which started corroding at the joints 2-3 years later. (It was a "technium" bonded frame, with 531 tubing and forged alloy lugs). Anyway, the LBS dealer took 10 seconds to say "that shouldn't have happened", ordered me a new replacement frame and swapped everything over when it arrived.
 
If you are really sure that the rust is just on the outside surface and just messing with the paint then you can just file it off with some sand paper. You can start with some semi-semi-aggresive (sorry my french) sand paper and then move on to finer and finer, being sure that you -dont remove any metal- since this is a reynolds (valuable) frame. Once you removed the rust you can just check if this was paint contamination or frame corrosion. You can always run a camera inside the frame... :big-smile: Really though... if you dont care about the appearance too much and if this is just external you can just seal it off with some heavy duty protective cover (hey whats that an extra 2 grams or something?) and paint it over with some paint. Plastering might work better for car panels because they dont play any structural role...
 
According to the Bianchi website, there is a 5-year warranty on frames. It says that "proof of purchase is mandatory". I kept the receipt on this for a long time but I'm not sure I can put my hands on it now. I'm looking. But I'm also not sure if they'd accept the blame on this one. Three years and umpteen thousand miles. Even though the one spot looks like it's just bubbling up from under the paint, it's up to their discretion. I'm going to pursue it but I think I'm on my own now.
 
Originally Posted by doctorold .

According to the Bianchi website, there is a 5-year warranty on frames. It says that "proof of purchase is mandatory". I kept the receipt on this for a long time but I'm not sure I can put my hands on it now. I'm looking. But I'm also not sure if they'd accept the blame on this one. Three years and umpteen thousand miles. Even though the one spot looks like it's just bubbling up from under the paint, it's up to their discretion. I'm going to pursue it but I think I'm on my own now.
Ideally, the LBS from whom you bought the bike should be able to generate a xerox of the receipt for you ...

And/Or act as the liaison for the replacement of the frame.
 
Originally Posted by doctorold .

Yup, I have been in contact with them and they are going to get the ball rolling.
Never hurts to ask. Could be it was an issue of improper frame prep which affected a number of samples and that Bianchi already knows about the problem. Let us know what they decide, and good luck.
 
No big deal. Braze joints are sometimes not properly prep'ed for painting by the builder and have rust going on under the paint before it leaves the factory.

Sand/wire brush. Kill remaining rust with any weak acid. Rinse acid and dry. Prime and paint after masking. Clearcoat to suit.
 
I live close to the ocean so rusting is a problem for me. I think you should also use rust prevention methods also.

These tips should help a bit.
http://www.wikihow.com/Remove-Rust-from-Metal