A cool idea that probably won't work.

Well, I am not a materials scientist, so probably my misinformed
opinions will be nearly of meaningless, but...

I think that we don't know if deposition of aluminum and oxygen in
vacuum will create sapphire sheets. I think that the process known
nowadays for creating synthetic sapphires involve high pressures and
temperatures, which is radically different from the vacuum-based
process that you are proposing. So I guess someone would have to make
experiences with vacuum chambers in order to answer your question.

On 7/8/06, Xenophile wrote: