I am curious. What could you possible want to install for 150 to 200 years?

I would imagine given that amount of time dissimilar metals will corrode
significantly. Probably to the point of failure. Is it vital that they
are dissimilar metals and that they are irreplaceable for 150 years?

Aluminium is an interesting case because it is actually a highly
reactive metal* but in the presence of oxygen it forms a tough oxide
(rust) coating that stops further reaction. Perhaps as long as you don't
continually damage that coating (e.g. they joint is completely
immobile) it might last quite well.

*You would be amazed at the speed of the reaction. I have seen aluminium
foil nearly catch alight after it has had the oxide coating removed by
chemical treatment.

Graham

Anna Kettle wrote:
On Sun, 27 Feb 2005 23:10:37 +0000, The Natural Philosopher
wrote:


Its in a well ventilated and well maintained attic space so water will
not be a problem


Mmm. You should be OK then for 15-20 years..


Now you've worried me again. I was thinking more like 150-200 years

Anna
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
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