Help preserving bubbling flaking paint.

[tlaverty79]

Hi, I have a Cannondale f800 I'm trying to fix up for my uncle.
Problem is oxidation under the paint causing it to bubble a flake off on the down tube and bottom bracket shell.

What's the best option here to preserve or repair it?

Most of what came off did so with a normal garden hose with poor water pressure.

Thanks.

Any help would be great.

Tony

 

[Retro Spud]

You can see the oxidisation taking place - the thing is the paint is no long stuck to the main structure but floating on bed of powdery corrosion

Personally I think you’ll loose the lot as the blistering runs the whole length of the underside of your down tube and will continue to spread like wood rot in timber if left untreated (but then I’m not telling you something you don’t already know)

When this has happened to many of my RS Judy lowers and when I’ve stripped them even on the parts that the paint hasn’t visibly blister you can see worming taking place.

Such a shame as I can see why you’d want to stopit as it’s a nice frame

 

[tlaverty79]

Re:

Thanks,

It's been in constant use for 20 odd years in a damp Glasgow. My uncle isn't too bothered, he just wants his transport back.
After removing the damaged paintwork what a the best course of action?
T

 

[legrandefromage]

These frames are very very thin walled and I saw a few that had been blasted prior to painting and the stuff used had holed the frame.

All I can recommend here is a brass wire brush on a drill and use that to take the worst off then paint with etch primer

If you are careful, it should come out ok.

 

[retrobate]

Re:

If all you are worried about is stopping the corrosion and are not bothered about the cosmetics I would sand any flaking/bubling paint off and sand away any corrosion and pitting.
Treat the bare aluminium with Alocrom (this may have been banned as its not nice stuff) then etch prime the affected areas.
Then prime and paint as normal.

 

[tlaverty79]

Re:

Excellent. Cheers guys

 

[tlaverty79]

Re:

Excellent. Cheers guys

 

[phill77]

Soda blasting is a great way to remove paint from fragile metalwork. I haven't even bothered painting my 6061 frame since and it has not corroded beyond going a nice matt colour in 8 years.
I only paid about £30, and it was money well spent compared to hours of hard work sanding.

 

[tlaverty79]

Re:

Cheers