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Aluminum Panels (not VW)

karmannghia60 - June 24th, 2003 at 09:33 PM

I was checking a car on the weekend, bonnet, boot & doors had this weird bubbling all over and I mean all over. Looked like the rust bubbling you would get around normal door bottoms or sills but simply everywhere. The owner said those panels were aluminum and weren't prepaired properly but its not rust. Just chemical reaction which causes the paint to bubble. Is this true? Any damage to the panels or simply they just need stripping and repainting properly?
Cheers
Raf

his@hervw - June 25th, 2003 at 08:38 AM

Steel Rusts,,,, Ali oxidizes. Its lost its protective coating. Happens when air gets to the metal. Big job,looks like a white powder, and will brush off with your hand. If you put a brass coin or screw on the metal it will eat through in no time......

his@hervw - June 25th, 2003 at 08:38 AM

karmannghia60 - June 25th, 2003 at 09:49 AM

So panels need stripping, protection then re-spraying? Why do you say its a big job? Would the panels be damaged?

helbus - June 25th, 2003 at 07:32 PM

Quote:

Steel Rusts,,,, Ali oxidizes.

Rust is oxidisation - iron-oxide

The bubbles on the panels may be humidity blisters which is not necessarily reaction to the aluminium, but humidity that was trapped either between the metal ant the primer, or between the primer and topcoat. If the vehicle was puttied, this adds another possible layer.
If the bubbles are under the primer, then it is possible the aluminium has corroded.

The only fix in any of these cases is to fully remove all traces of the defective products.

his@hervw - June 25th, 2003 at 08:00 PM

Yep,,,, sorry,, Another thing is if the panels are attached wrong they will fail, because of two disimiliar metals in contact with each other, to far apart on the galvanic scale. The metal will pit deeply, where a rusted part has protection in a small way from the rust itself, the ali won,t. think that's right.....2c worth anyway:bounce