Paintwork issues

[brucers]

I have an alu frame bike with bubbling paintwork around the screw holes where the drinks holder fits. There is also flaking paint around the ends of the carbon forks.

Whats hint n tips do people have regarding preventing them getting worse. The forks I wonder if painting or clear varnishing over them will reseal the paintwork effectively.....also are there considerations with carbon and what liquids can be used without damaging the carbon itself? The bike is about 6 years old.

 

[Yellow Saddle]

You can't prevent it from getting worse but it will self-arrest after creating a nice eyesore.
The paint at those points bubble because of galvanic corrosion between the carbon and aluminium/steel parts glued and crimped in. The glue does not create a perfect insulator and a small electric current runs between the two parts, oxidising the aluminium which in turn lifts the paint. Putting clear varnish over it will do nothing.
Welcome to the world here the salesman and brochures and magazine (wannabe) writers don't tell you about carbon's dirty little hidden secrets.

 

[biggs682]

You can't prevent it from getting worse but it will self-arrest after creating a nice eyesore.

In the most easiest place to see as well normally

 

[youngoldbloke]

You can't prevent it from getting worse but it will self-arrest after creating a nice eyesore.
The paint at those points bubble because of galvanic corrosion between the carbon and aluminium/steel parts glued and crimped in. The glue does not create a perfect insulator and a small electric current runs between the two parts, oxidising the aluminium which in turn lifts the paint. Putting clear varnish over it will do nothing.
Welcome to the world here the salesman and brochures and magazine (wannabe) writers don't tell you about carbon's dirty little hidden secrets.

Is it safe to use forks where this is visible?

 

[Yellow Saddle]

Is it safe to use forks where this is visible?

Yes, apart from when there are obvious craters, cracks, holes and warning noises. None of these have ever happened, so close your eyes (to the ugliness) and ride on.

 

[brucers]

In the most easiest place to see as well normally

Luckily both areas are not highly visible. It's only the curvy bits where the wheel fits in that's flaking and the bottle holder covers most of the bubbling area. The bike looks lovely otherwise!

 

[brucers]

You can't prevent it from getting worse but it will self-arrest after creating a nice eyesore.
The paint at those points bubble because of galvanic corrosion between the carbon and aluminium/steel parts glued and crimped in. The glue does not create a perfect insulator and a small electric current runs between the two parts, oxidising the aluminium which in turn lifts the paint. Putting clear varnish over it will do nothing.
Welcome to the world here the salesman and brochures and magazine (wannabe) writers don't tell you about carbon's dirty little hidden secrets.

Thanks for that. Far too technical for my laymans mind but I get the gist!

 

[pclay]

I had bubbling paint that eventuallly start to peel off on my 4 year old Cannondale synapse. I used a bit of sandpaper to smooth out the paint, and then painted on with modelling enamel paint of the same colour.

 

[vickster]

Any recourse under warranty if you were the first owner and the frame has a lifetime warranty, a la Specialized fur example?

 

[brucers]

Any recourse under warranty if you were the first owner and the frame has a lifetime warranty, a la Specialized fur example?

I got it 2nd hand so a no go on any warranty.

 

[brucers]

I had bubbling paint that eventuallly start to peel off on my 4 year old Cannondale synapse. I used a bit of sandpaper to smooth out the paint, and then painted on with modelling enamel paint of the same colour.

I take it that it's stopped the bubbling from spreading?

 

[Yellow Saddle]

I take it that it's stopped the bubbling from spreading?

No, it can't stop the bubbling from spreading, it only removes current corrosion and starts afresh. The problem is with the use of two different metallic materials in close proximity. Carbon fibre composites in this case also acts like a metallic anode or cathode.

 

[pclay]

I take it that it's stopped the bubbling from spreading?

I will get a photo up tomorrow. The bubbling has not spread after 12 months.

 

[mjr]

I will get a photo up tomorrow.

<fx:nudge/>

 

[Globalti]

My first carbon bike had a few places where the very thick glossy brittle red paint had chipped so I took a tiny flake of the paint stuck to some Sellotape and went to Boots to buy some nail varnish. The sweet young shop assistant did a good job of helping me choose the nail varnish while making it clear she didn't believe my story; in fact at one point she actually said: "How about this one? This will look really nice on y....."

As I left I could imagine her heaving a sigh of happiness and thinking: "Thank goodness I did my customer inclusivity training!"