Re: [APML]: Storing TechPan

[Brad Wallis <wallis@pepe.jpl.nasa.gov>]

re: ZIP LOCK bags and FG purge or N2 purge for storing ....

When you go to store your Tech Pan in the refrigerator or in the freezer,
the enemy here is moisture....  If you freeze it in a purged hypering
tank that is *really* air tight that will keep the film the driest and
will preserve it the best...  If you place the film in a ZIP LOCK bag
for storage then you should place some dessicant into the bag ( indicator
dessicant is best since it tells you when it is saturated ) then
you will keep it dry and help the preservation of the hypered film.
Purging the ZIP LOCK BAG with FG or N2 is only useful for very short
storage periods ( like 1-2 days ) as the gas in the ZIP LOCK BAG leaks
out osmotically and you have your basic AIR in the bag after only 1-2
days ( tested with an O2 monitor and an N2 purge ).

Storing the film in N2 or FG in the freezer will preserve the hypered qualities
the best.  This is a chemical process and thus works as all chemical processes
work:  If you lower the temp by 6-7 deg C you will slow the process by a factor
of two ...

I will add a piece on the Storage of Tech Pan at our WEB SITE, I am trying to
fill in the need for FAQs for this mailing list.  
       http://voltaire.csun.edu/hints.html

Brad Wallis

for fun, visit:  http://www.jpl.nasa.gov/cassini