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  for Metal Finishing since 1989
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Dark Spots on Aluminum Casings

2006

I am restoring an old Ducati Motorcycle which has been lying around for the best part of 25 years. When trying to polish the outside casings, which should be a shiny surface, I am left with dark patches which seem to go deep into the metal. Can this be corrected or is it something I have to live with.

Any help would be appreciated, as replacing them could be a very costly business.

Many thanks in advance.

Steve Day
Hobbyist - Bridgend, South Wales, UK

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2006

Steve this can be pitting in the initial casting of the covers, the ages sounds about right for this to be part of the problem.
The alternate scenario is that this is oxidation, I would suggest getting the covers bead blasted at a welding shop, that would clear out the rust and let you see how bad the damage is, if it's too bad I would highly suggest replacing them. If it's not too bad I would suggest sending them off to either get plated or powder coated. There are some bright powder coats available now and they would keep this from being a problem again, additionally it would impart some more strength into the covers.

I don't know which of these it is, but good luck.

Marc Banks
Blacksmith - Shawboro, North Carolina

Really appreciate the advice, I might try the powder coating option, someone else has told me similar.

Thanks,

Steve Day
- Bridgend, South Wales, UK
2006