[APML]: Re: Vacuum pump

[ipper@juno.com (C B IPPER)]

On Tue, 1 Oct 1996 09:05:56 -0700 Brad Wallis <wallis@pepe.jpl.nasa.gov>
writes:
>
>a single stage mechanical pump like the marvac will cause no emulsion
>problems ... this is a myth ... even a high vacuum pump that runs down
>to < .5mm ( 500 microns ) in 5-10 sec and then runs down to 1 micron
>over the next few hours of serious film outgassing causes no such 
>problems
>
>I have spoken to marvac... can post the specs for this low vaccum 
>mechanical
>pump if anyone is interested ....  it will perhaps reach a vacuum of
>a few mm pressure as its best vacuum ....
>
>Brad Wallis
>
Hi Brad,
  After reading your information on the myth's of vacuum conditions, 
the following questions I would like to learn more about?
  The conditions in question are: low end  vs. hi end pumps.
Can similar results be achieved by flushing dry nitrogen through 
your hypering system for a certain time period, at a particular pressure,

and temperature.   In between these intervals, low end vacuuming would
occur.
If you have tested both of these situations, have you noted any
difference in the 
brittleness of the film emulsion, color vs. 2415 ?  Also how they react
to the 
actual hypering  and exposure conditions?    Moisture always a problem!

Carl Faulkner