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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.space
Subject: Re: Speculations on Shuttle Disaster
Message-ID: <6384@utzoo.UUCP>
Date: Sat, 8-Feb-86 21:25:30 EST
Article-I.D.: utzoo.6384
Posted: Sat Feb  8 21:25:30 1986
Date-Received: Sat, 8-Feb-86 21:25:30 EST
References: <8601291923.AA01088@s1-b.arpa>, <8602050248.AA01753@ucbvax.berkeley.edu>
Organization: U of Toronto Zoology
Lines: 22

> I'm sure aluminum would burn in the presence of pure O2.
> I think it's just above magnesium in the periodic table;
> Mg is used for flares and incendiary bombs.

Aluminum actually burns fiercely and is hard to extinguish, but its
saving grace is that it doesn't ignite easily.  Consider thermite:
powdered aluminum plus powdered iron oxide.  Ignite it -- not easy --
and you get white-hot molten iron plus aluminum oxide, at 5000+ F.
The aluminum is doing all the burning; the iron is just along for
the ride.  Once started, thermite will burn underwater.  But even
burning magnesium isn't hot enough to *ignite* thermite; fairly
extreme measures are needed.

> ...I think the Exocet missile did the same [set it on fire] to the aluminum
> hull of the british ship lost off Argentina.

HMS Sheffield's hull and superstructure were steel, actually.  Some British
warships do have aluminum structures, and there was some confusion about the
matter in the news media.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry