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Re: [APML] Cheap Dessicant to store film with
Jason;
Don't use 'Damp Rid', yuck, that's nasty stuff. Use Silica Gel
"crystals" instead, not the kitty kitter stuff or round bead silica gel.
Crystals have a much larger surface area.
A source of Silica Gel crystals in bulk is
http://www.silicagel.net/index.asp. 1kg (2.2lbs)of Indicating Silica Gel
for only $15. That's the best price I've found in the 15yrs I've been using
Gel.
Get the Indicating (blue colored) silica gel. The recomended
recharging of Indicating Silica Gel crystals is 4hrs, no higher than 300F.
Higher than 482F Silica Gel completely dehydrates, looses its absorbtion
properties, breaks down and creates dust.
I use 1lbs of 3 to 8 mesh size crystals in my dry air purge system. It
works very well down here in soggy North Central Florida.
Moisture is a major contributor to fungus on optics coatings. Another
use I've come up with is a "Telescope Tampon" for my 6" AP refractor and 10"
SCT. Sew up a little bag 1"dia, about 4" long from cotton velvettine. Turn
the velvet side inside the bag to act as little filters closing off the
weave of the cloth. Fill the bag with silica gel and sew the bag closed
adding a nylon string to loop over the focus knob. Insert the tampon inside
the OTA to remove moisture inside between observing sessions or for long
term storage...joe :)
"May You Go Among The Imperishable Stars"
Joe Mize: jmize@svic.net
StarFields Observatory http://www.cav-sfo.com
Chiefland, FL 29:24'33.4"N 82:51'37.7"W
Moon Phase: http://tycho.usno.navy.mil/cgi-bin/phase.gif
----- Original Message -----
From: "Richard Klappal" <klappal@xnet.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Wednesday, August 04, 2004 12:30 PM
Subject: RE: [APML] Cheap Dessicant to store film with
> You can also use the silica-gel packages that you find packed with various
> cameras, lenses, electronics, ...
>
> Many of them can be regenerated by gentle heating, but I don't recall how
> warm the need to get. Its not much.
>
> Places like American Science & Surplus (www.sciplus.com, I think), Edmund
> Scientific, or similar, may also carry them; they are used in chemistry
> laboratories for sample drying.
>
>
>
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of Lane, Jason R
> Sent: Wednesday, 04 August, 2004 11:12
> To: Discussion of Film Astrophotography
> Subject: [APML] Cheap Dessicant to store film with
>
>
> Hello all,
>
> One of the objectives of hypering film is to remove moisture from the
film.
> >From my limited knowledge of how hypering works, the removal of moisture
is
> one of the reasons hypered film has greater sensitivity and/or less
> reciprocity failure. Since I don't have access to a hypering system nor
> will I have one anytime in the near future, I've always wondered if
storing
> film long-term with dessicant would be of any benefit. Naturally it
> wouldn't be as helpful as hypering, but maybe it helps a little bit
without
> the large investment that hypering requires.
>
> I recently discovered that Wal-Mart sells a product called "Damp Rid" in
> their cleaning supplies section. This is 18oz of calcium chloride, and
the
> product is designed for use in damp areas of the house to reduce musty
odors
> and humidity. The package is relatively inexpensive...less than $10. The
> container has an insert which divides it into upper and lower sections.
> Normally you would put the calcium chloride in the upper section to let
the
> water drain down to the lower section, but for this I put the calcium
> chloride in the lower section, 5 or 6 rolls of film in the upper section
and
> sealed it in a Ziploc bag and stored it in the fridge. The ziploc is
going
> to be temporary until I find something that gives a better seal (I was
> thinking a big Mason jar). Through normal use, some of the rolls will be
> stored in there over the course of several months, so I believe I'll get a
> good set of data points from a few weeks' storage to a few months'
storage.
> I can then compare these to photographs I've already taken of deep sky
> objects and see if there was any effect. I can also try variations on
this
> theme, like baking at low temperatures to help the process along.
>
> Thoughts?
>
> Cheers,
> Jason
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