Aluminium Frame Repainting

[Andy]

I have a Cannondale Caad 5 road frame which I have used throughout all weathers (okay I live in Scotland so mostly rain and wind ). It is is still in reasonable condition however at most of the frame joints the paint is showing signs of the aluminium corroding. The bike has been used extensively in all weathers right throughout several winters, and has been cleaned, dried and lubricated where required.

Now before you all jump up and down and tell me that Aluminium doesn't corrode, I know that it does not "rust" in the same way as iron or steel does, but it does form a white powdery, protective corrosion on it's surface almost instantly when exposed to air. This is very hard to remove as the bond between the corrosive coating and substrate Aluminium is a strong one.

It looks like the stresses created at each joint area, (around the head set, on each of the drop outs etc) have exarcebated the "corrosion build up" to the point where the surface is no longer smooth but bumpy and rough. The paint itself is not cracked anywhere (yet) and I have had the frame checked out by a reputable mechanic who says that it does not currently pose a probelm with respect to weakening but through time will do so.

Point of the post is, has anyone else experienced this and what did they do about it? Instead of consigning the frame to being a winter hack (can't currently afford to buy a new "summer" bike), I am considering getting the frame sand blasted and repainted then the whole thing rebuilt with what new bits I require.

Can anyone throw some advice my way and let me know if they have done similar and where they went, how much etc. etc.

I have looked a a couple of websites and it would seem that I can get this done for maybe no more than £200 which on the face of it seems reasonable, but would like to hear from others that have maybe come across this.

Thanks in advance.

 

[mickle]

Eny fule know aluminum does oxidise although I'm not sure that without the use of some jolly expensive equipment any old grease monkey can tell at what point surface oxidisation has an effect on the structural integrity of a lightweight bike frame.

Argos Racing Cycles in Bristol are authorised Cannondale re-finishers and are highly respected for their quality of workpersonship by this member.

 

[Andy]

Eny fule know aluminum does oxidise although I'm not sure that without the use of some jolly expensive equipment any old grease monkey can tell at what point surface oxidisation has an effect on the structural integrity of a lightweight bike frame.

Argos Racing Cycles in Bristol are authorised Cannondale re-finishers and are highly respected for their quality of workpersonship by this member.

Thanks Mickle will have a look at Argos. No, unfortunately any fool does not know that Aluminium oxidises, the amount of folk that say that it shouldn't have happenend because Al does not rust would surprise you!

As for any old grease monkey, the guy that looked at the frame was not, he is a fairly well recognised bike mechanic with years of experience in frames, wheel building etc. He was using his experience to say that at this stage the oxidisation would not cause any problem but that longer term it may well do so.

Thanks for the info though.