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Discussion Starter · #1 ·
Hello, all.
I have a 2003 Cervelo P2K that I use both for workouts and TTs. Due to an accident I had last Oct. I can no longer use my Giant TCR2 (back problems) and can only use the Cervelo. I bought it over three years ago and it's still in great shape. However, lately I have noticed a little bit of paint coming off and minimal corrosion on the holes on the frame where the internal cables go into. I really love this bike and although some may be able to buy bikes regularly, for financial reasons,I need this bike to last me a long, long, long, long time,...
Is this something to worry about? Can this corrosion ruin my bike? I live in South Florida (high humidity) and I sweat a lot !
I would appreciate if any of you wrench experts could give me some advice on how to treat this problem.
Thank you.
 

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I would definitely recommend taking some corrective action on that. If you let the corrosion go it will only get worse, weaking the metal around the corrosion and leading to stress cracking.

Fixing it is pretty straight forward. Remove all the corrosion, prime and repaint. When removing the corrosion, use non-metallic sandpaper unless it happens to be aluminum oxide cloth. Clean the metal with plain water and then prime/repaint it as soon as it's dry. Ideally you would anodize the aluminum before priming and painting, but I was only an aircraft painter in the Navy and I don't know if the anodizing chemicals are generally available. Chemical anodizing puts a strong corrosion barrier over the aluminum and also helps the primer adhere.
 

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Also make sure you clean the inside of the holes and then prime and paint them. Use a small, pointed brush, load it with primer/paint and run it around the inside of the holes.

In many cases, that's the very area where the corrosion started. When frames are finished at the factory, the insides of these small holes often don't get enough primer or paint.
 

· classiquesklassieker
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Cable corrosion?

Bill from WPB said:
Hello, all.
I have a 2003 Cervelo P2K that I use both for workouts and TTs. Due to an accident I had last Oct. I can no longer use my Giant TCR2 (back problems) and can only use the Cervelo. I bought it over three years ago and it's still in great shape. However, lately I have noticed a little bit of paint coming off and minimal corrosion on the holes on the frame where the internal cables go into. I really love this bike and although some may be able to buy bikes regularly, for financial reasons,I need this bike to last me a long, long, long, long time,...
Is this something to worry about? Can this corrosion ruin my bike? I live in South Florida (high humidity) and I sweat a lot !
I would appreciate if any of you wrench experts could give me some advice on how to treat this problem.
Thank you.
I suspect that this is from your cables corroding, not from the frame itself. Try rubbing it off and see if the frame itself is the issue. Water can easily can trapped in the cable interfaces, that's why I recommend applying a light layer of lube inside the cable caps.
 

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orange_julius said:
I suspect that this is from your cables corroding, not from the frame itself. Try rubbing it off and see if the frame itself is the issue. Water can easily can trapped in the cable interfaces, that's why I recommend applying a light layer of lube inside the cable caps.
What color is the corrosion? Red/rust would be the cables. I think that aluminum oxidation would look white or grey...
 

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I work in a metal fabrication facility and here is my 2 cents. Aluminum oxidizes which typically only affects the surface. This surface oxidation protects the underlying metal. I would not worry about structural integrity with the aluminum. There are bare aluminum boats all over the northwest in ocean service with no paint. They only have surface oxidation. Granted they use cathodic protection, but that is due to salt water.

One other possibility is: Where the cable enters the frame - is there a metal sleeve or thimble?? One thing to watch for is dissimilar metals. Aluminum and steel do not like to touch each other. If the paint has worn off the aluminum at that location and the metal thimble is touching it (along with the sweat) will cause corrosion to both metals. This type of corrosion will actually hurt the aluminum due to a chemical reaction. If this is the case, you need to remove the corrosion (sandpaper will work), clean the area and repaint. I would then put some tape (electrical) around the thimble (housing end cap) to keep the metal from wearing throught the paint.
 

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Discussion Starter · #8 ·
Thank You ==> White corrosion on sleeve

Thank you all for the time you took to respond to my problem.
There is a sleeve where the cables enter the frame, and it is on the sleeve where the cables touch the metal where there is WHITE corrosion, so I guess I could safely assume that the sleeves are aluminum also.
Since I live in So Florida pretty close to the ocean, I think the cathodic protection might be a good alternative. Anybody know where this can be obtained?
 

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Bill from WPB said:
I think the cathodic protection might be a good alternative. Anybody know where this can be obtained?
If I understand it correctly the "cathodic protection" is actually a plating of a sacrificial layer of a more anodic (i.e. more likely to corrode) metal. Thus this is not a practical solution for you. And I disagree with tim, this is definitely something that could be a problem. In situations where you seem to have bare aluminum that doesn't corrode it has actually been anodized. Thus, although it isn't painted it does have a protective barrier over the metal.

If your aluminum frame is corroding, it WILL eventually weaken the metal and crack. I was a painter and structural mech on aircraft in the Navy and I have seen it happen.
 

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If your aluminum frame is corroding, it WILL eventually weaken the metal and crack. I
Absolutely. Talk to any salt water skipper about that and they'll tell you many stories about aluminum spars and fittings corroding and failing. And remember, sweat isn't far removed from salt water.
 

· Cycling Boob
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question from this topic. i also bought a used cannondale with bubbling going on the paint. I know that this might be from corrosion and so I was wondering is it really necessary to remove the paint? i know that aluminum oxide is sort of like a "protective layer" so wouldn't that somewhat stop future corrosion?
 

· Call me a Fred
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Aluminum does corrode when exposed to anything that is acidic or basic. Sweat is fairly acidic.
 
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