Alum corrosion

[BillBB]

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 anyone could give me some advice on how to treat this problem.
Thank you.

 

[AussieRob]

I am going to say AL doesn't corrode (which is, strictly speaking, not true*), are you sure the frame isn't just dirty, or that the corrosion is not from the cables.

*google "passivation" if you want to know the details

 

[artmichalek]

I am going to say AL doesn't corrode (which is, strictly speaking, not true*), are you sure the frame isn't just dirty, or that the corrosion is not from the cables.

*google "passivation" if you want to know the details

Aluminum will corrode, particularly if sweat or salt water gets on it. The best thing to do in this case is clean up the corrosion with some fine grit (300+) sand paper then cover the spot with automotive touch up paint.

 

[RickF]

Aluminum will corrode, particularly if sweat or salt water gets on it. The best thing to do in this case is clean up the corrosion with some fine grit (300+) sand paper then cover the spot with automotive touch up paint.

True. The worst thing you can do is clean up the corrosion and NOT cover the spot with automotive touch up paint. you would be better off doing nothing than cleaning, but not painting aluminum.

The major difference between aluminum corrosion and iron or steel corosion is that the corrosion on aluminum does not progress like it does on iron or steel. The oxidized aluminum, if it is not in a place where friction will wear it off, will protect the aluminum under it from further oxidation. Only if the surface oxidation is rubbed off will the aluminum under the oxidized layer oxidize. It sounds like the place where you are seeing oxidation is at a place where there is constant friction, so the advice to clean and paint is good advice.

With iron or steel (an iron alloy), because iron has two oxidative states, a layer of oxidation will speed the oxidation of the metal under it. It is sort of a chain reaction (or a cancer) that continues to progress until all of the iron is in the Fe++ state.