Opinion sought on aluminium corrosion....

[jpgibson]

I've got a Cannondale Six 13, which is the carbon/aluminium frame ( top tube,downtube carbon, rest aluminium save the forks).The frame is about 5 years old.As I had with a previous Merida, there is white powdery ' corrosion' at the aluminium/carbon interface ie where the aluminium is exposed.
Now, I commute 150kms+ a week on my pushie(s) and although I think ( hope) it's sound I thought I'd ask the question to the collective wisdom.The carbon tubes are inserted deep into the aluminium, so there is quite a bit of overlap.


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thanks.
jonathan

[reefer]

Just looks like surface corrosion to me, nothing to really worry about unless you can see any raised, bulging or flaking areas of the aluminium which would indicate more in depth problem.

You could hit it with some scotchbrite and then a good preservative, such as Boeshield or even a product like WD 40 to keep the base aluminium protected. You would need re apply the preservative often though, say every time you washed the bike and relubed it.This should stop any real growth over time.

To treat it properly, you would really need to remove the all corrosion, hit it with an alodine solution or the like and refinish the item. Not really worth it for such minor corrosion unless its of great importance to you.

[jpgibson]

Phew,and thanks!

[QuangVuong]

I'm looking at older Al lugged carbon frames, and Id be more worried about the galvanic attack on those.

But I am interested to find pics of the joints where the corrosion is so bad that it'll break in no time. Anyone?

[wurtulla wabbit]

Looks like usual lacquer reaction with weather/moisture.
Certainly doesn't look structural.

[toolonglegs]

Common fault on the clear coated System6's as well... my System6 was replaced under warranty, doesn't effect the painted ones in the same way so it is obviously a reaction with the clear coat.
Unlikely to weaken the frame unless it is really bulging.