George,
I would tend to agree with Martin that the coating is most likely
aluminum oxide which forms a protective coating and passivates the
metal. Removing it would be counterproductive because a new oxide
coating will form almost immediately. However, you describe the coating
as "powdery" which suggests that, if it is an oxide, it may be the
result of vigorous oxidation. It could also be another aluminum
compound, created possibly by a reaction with, for example, road salt.
I like Fred Sisson's suggestion; especially since it seems to solve the
problem. What more can one ask!
Chuck Vandergraaf
'52 +4, P.2473/V.345.ME
'85 Chrysler LeBaron Turbo
'86 MR2
Pinawa, Manitoba, R0E 1L0
Canada
vandergraaft@aecl.ca
>----------
>From: Martin Kurrein[SMTP:mograces@mkurrein.co.uk]
>Sent: August 5, 1997 1:35 AM
>To: Sarah
>Cc: Morgans@Autox.Team.Net
>Subject: Re: Aluminium alloy bodywork
>
>In message <33E4E3D4.1C50@virgin.net>, Sarah <linda.h@virgin.net> writes
>>This isn't strictly a Morgan question but may be of interest to those with
>>cars
>>with aluminium bodywork. In
>>order to help pass the time while I am on the waiting list, I have recently
>>bought a 1953 Armstrong-Siddeley
>>Whitley (which was a rather nicely-styled 4-door saloon with bodywork in an
>>aluminium alloy and steel wings).
>>The underside of the bonnet appears never to have been painted and is
>>covered in
>>a "powdery something" which I
>>have been led to believe may be the aluminium oxidising. Does anyone have
>>any
>>similar experience and could
>>suggest how I should treat it and, subsequently, prevent it from recurring ?
>>
>
>Almost certainly aluminium oxide. There are a number of possible
>solutions but the oxide itself actually forms a semi-protective coating
>itself. Once the oxide forms it does not (unlike rust on steel) continue
>to eat away at the substance of the metal.
>
>You can try polishing it up and then coating in clear laquer or
>aluminium based paint - or simply leave it as it is.
>--
>Martin Kurrein - The older I get the faster I was.
>mograces@mkurrein.co.uk
>www.mkurrein.co.uk/ - The Morgan Motor Company Challenge
>
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