Has it been a while since you ran the system?
Perhaps the oil in the roughing pump needs to
be warmed up and outgassed a bit through the
interstage ballast valve, assuming yours has one,
or the exhaust if not.
How new is the oil in the roughing pump? I assume
you haven't had any disasters in the chamber that
could have outgassed anything.
Wipe down all internal chamber surfaces with anhydrous
alcohol perhaps? At that high a pressure, I think
of things like water vapor or leaks.
On Feb 12, 2013, at 7:55 PM, Guy Brandenburg wrote:
Just tried and failed to aluminize a mirror because the pressure would not go below 1.7x10^-4 torr; as a result the coating was semi transparent. If it goes below 1.0e-4 all is good. This is unusual. Persisted even when i tightened stuff up.
Any suggestions?
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- Bill "Gomez" Lemieux,
The Highland Tinker
