Bicycle Mechanics - Corrosion with Aluminum?

When I got my Trek 7000 (ZX Aluminum series, Easton ProGram Taperwall Alum), it had a nasty gash on the right chainstay I guess coz the chain hit it? I'd like to fix this if there's a chance of corrosion here. Anyone know how?

Touch up paint? The only corrosion problem is with salty water (sweat) which can cause the paint around the ding to bubble up and look nasty. Aluminum does not actually rust just gets a bit of corrosion on it occasionally.

-Ryan

Clear fingernail polish! - Or if you want to take the time you can try to match the color with the bike. The fingernail polish seals the scratch/gash over, keeping water and contaminants from getting to the area. I've used it a ton of times, Road(steel frame) and mountain(aluminum) and it seems to do the job great. Picking up a chainstay guard for a few dollars from your LBS or the net will keep anything like this from happening again and will quiet down the ride some (You won't hear the chain slapping against the chainstay).

-Moab

Good ideas, thanks. :D

fill the gash with epoxy resin sand then paint or try j b weld, liquid metal but fill thew gash first

If the gash actually took some aluminum out of the metal, you probably do want to add some filler, like JB weld. Might want to sand the area lightly first. The filler will help restore some of the original strength. This shouldn't be too much of a concern unless the gash extends a significant fraction of the tubing's thicknes (> 1/4)
After you've filled it (if it needs) and sanded, go with the polish, although it isn't really necessary. One interesting thing I learned in my materials science class is that aluminum isn't actually immune to corrosion, it just forms a thin but fairly durable layer of corrosion that protects itself!

Sometimes it forms a thin protective layer that protects its self. I could show you some old two stroke cases that look like they have the metallic version of leprosy.

Originally posted by Rev.Chuck
Sometimes it forms a thin protective layer that protects its self. I could show you some old two stroke cases that look like they have the metallic version of leprosy.

I've heard that's only true if the aluminum is Alclad, meaning it's got a layer of pure (1000 series) aluminum rolled onto the alloy surface. This layer oxidizes (forming aluminum oxide) protecting the alloy underneath.