On Nov 2, 4:59 am, "Roger (K8RI)" wrote:
On Wed, 31 Oct 2007 20:32:08 -0700, Fred the Red Shirt
...
He has a quartz bell jar that is (again IIRC) about 18"in diameter and
close to 18" tall or a bit more. Ultimate vacuum is probably on the
order of 1.2 or 1.3 X 10^-6 or -7 Torr although it doesn't need to go
that high.



That sounds like several thousand dollars of equipment.

I think I'll look for someone else to do it for me. They usually
overcoat them too, though if I were doing my own, more frequent
recoating would be plausible.

--

FF