bubbled paint - problem?

jdd

Maximum Pace
Hardest Crash
Jul 26, 2008
2,511
638
133
Kanazawa
#1
This is an ancient aluminum frame. Among other things, I'm going to replace cables this week. I have new clips, but since they don't seem to last too long, I'm also considering tie-wraps (which also don't last, but are easily replaced). Maybe even tape.

Anyway, is the bubbled paint a problem? (pins from the old clip still in the holes)

proxy.php?image=http%3A%2F%2Fi4.photobucket.com%2Falbums%2Fy142%2Fjdd489%2Fbubbledpaint_zps9fb3908b.jpg&hash=96bc2ade4de84e4d380d02b03dfea9d0
 

GSAstuto

Maximum Pace
Oct 11, 2009
945
242
103
tokyo
www.roadfixie.com
#3
Evidence of corrosion. You will need to sand it all away, etch, then zinc chromate it (inside and out) , prime and respray. Corrosion on aluminum will create a weakened section that will, in time, fracture completely. What you see on the outside may be even less than what's happening on the inside of the tube, btw. It's common to get this type of corrosion where 2 different metals come in contact. To avoid this, make sure you use similar metal (or more inert) as fastener. (alloy, Ti or stainless). Depending on where the corrosion is happening, the risk of failure may or not be catastrophic. (Imagine yourself bombing downhill at 60kph and that tube breaking - what would be the outcome?)
 

jdd

Maximum Pace
Hardest Crash
Jul 26, 2008
2,511
638
133
Kanazawa
#5
The clips I've used are plastic, as are the replacements I have. Rather than a different metals reaction, I was thinking the clips concentrated sweat and maybe provided an opening to get under the paint.

It's not worth a pro re-do, and if the inside is as much an issue as outside, then doing it myself will just be a halfway job (and will look uglier than sin). So I think I'll just leave it as is (thanks for the responses), take it easy on downhills, and try to get a few more seasons out of it. And Cannondale might've overbuilt it a little to begin with...