Modern Vespa

Hi, I recently bought a Vespa ET2 as a renovation project...things are going OK but I've discovered a strange white powder/dust that seems to be beneath the paint over the engine......hard to explain fully so please have a look at the photos.

It looks awful so my plan was to remove the silver paint and subsequently the white powder and then repaint......I just don't want to poison myself in the process.

Does anyone have any idea what it could be?

Thanks as always.

Paul

Corrosion.

That looks to me like oxidized aluminum. A lot of it.

Thanks both - so if its oxidizing aluminum would it be best to remove and retreat?

Many years ago, I looked at a moped with similar white powdery corrosion. Turned out the bike was stored next to pool chemicals. I've also seen this on my sister-in-law's Vespa. She lives near the ocean and the salt water in the air ate away at all the metal parts.

Classic aluminum oxide, indicative of having been stored in an unusually corrosive environment, or having been naively sanded down and repainted without proper preparation. It looks like somebody already tried to purge and paint that cover once already, and it obviously didn't work too well. Interesting observation from Mopedlar of pool chemicals potentially being involved - I was also going to suggest proximity to salt water, and perhaps even a flood. You see this a lot on aluminum boat parts. It's difficult to imagine how that might have taken place without significantly affecting the other parts of the scooter.

Aluminum is very difficult to keep painted in the first place, and aluminum oxide is very difficult to remove once established because it is so hard. It is actually used as the grit on many types of sandpaper.

The right way to proceed with that is to hit it with sand in an air blasting cabinet, and then to coat it with two-part aluminum primer within seconds of removal from the cabinet. You might be able to take it to a metalplating shop to see if they can do that chemically, and re-anodize the surface, but that might be prohibitively expensive.

Another take after another look: the coating on that might be "powder coating." That can be replaced, and isn't too expensive, but it REQUIRES the underlying aluminum to be free of existing corrosion and sealed/coated, or it'll just happen again in a year or two.

Thanks everyone - your help has been great

I have it too on my GTS, though a lot less of it. If I whipe the alu parts with my finger, the powder will be on my finger. Corrosion indeed.

My garage gets pretty moist during Winter time, so that's most probably the cause.

From an aluminium construction company I did some work for, I learned that the corrosion on aluminium functions as a protective layer.

But then again, they were building helidecks, which are probably made of a completely different grade.

That is correct. This aluminium cover will not rust through as when it would have been made out of steel plating. But it does not look nice.

Technically the best way to protect aluminium and make it look nice is to anodize it, which is nothing else then a well controlled way to oxidize the surface. Aluminiumoxide is one of the most stable compounds you can find here on earth. If done well nothing will ever come to it.

But in practice, and I think it is most probably a matter of cost, such parts and also light alloy wheels and so on are painted. It looks like it is anodized but it isn't.