Aluminium Jaguar

[MG David]

I have just bought myself a 2004 Jaguar XJR. It has an aluminium body.

While the car has been to the moon and back it still drives wonderfully and looks great until you get very close.

Around the wheel arches lips there are a few blisters in the paint, presumably the result of stones followed by salt water. Having not worked on an aluminium car before I have some questions:-

If this was a steel car I would expect there to be a web of rust veins radiating from the blister so that if I cleaned it up there would be a a patch 4 times the size of the original blister. Should I expect the same with aluminium?

Aluminium develops an oxide layer very quickly. Do I need the metal to be freshly bright before I paint it with epoxy primer or can it be oxide dull provided the corrosion is removed?

Should I treat the aluminium with anything before the epoxy goes on?

Any hints from anyone who has worked with aluminium would be welcome.

 

[piman]

Hello David,

I had an aluminium bodied car once, but that was aluminium on a small diameter tube framework and there was galvanic corrosion. The advice I was given was to strip the paint in that area(s) and assess the extent of the corrosion. Is the area double skinned ?
I don't think that painting over the oxide is a problem as it is a sound surface, although you will likely rub down the metal just before painting anyway?

Alec

 

[500e]

We work on a lot of ally to get good bonding.
You have to remove ALL corrosion\ oxide before coating, there is no short cut.
To remove finish we blast with different materials, plastic grit, soda, or aluminium oxide, then treat with Xiameter OFS-6040 Silane coupling agent, this works at a molecular level to help bonding.
If you want to read the chemistry the link will help, the results with\without are chalk & cheese
http://www.dowcorning.com/content/publishedlit/26-1402-01.pdf

The mantra is clean material, dry heat \no humidity, if possible treat with Xi, if not get the coat on soonest! minutes not hours, remember Primer is not waterproof it absorbs moisture from atmosphere so again minimum time to at least first top coat.
Painted alloy boats Nightmare, ally cars Aston's not much better (steel & alloy) aircraft parts even more agro.

 

[MG David]

Thanks for the information about Xiameter OFS-6040 Silane.

Where can one buy it and what sort of quantities does it come in?