Before you get to this point you should have already
used the charts above and determined how much of the particular
desiccant you're interested in you need for the size of the storage
containers you'll be using. Once you know that you're ready to put
them it into use.
Although they perform different functions, desiccants and oxygen
absorbers are used in a similar fashion. They both begin to adsorb
their respective targets as soon as they are exposed to them so
you want to only keep out in the open air as much desiccant as you
are going to use up in fifteen minutes or so. If you'll be using
oxygen absorbers in the same package, place the desiccant on the
bottom of the package and the oxygen absorber on the top.
If your desiccant is pre-packaged, that's all there is to it,
just put it in the package and seal it up. If you have purchased
bulk desiccant you'll first need to make your own containers.
I use indicating silica gel for practically everything. My usual
procedure is to save or scrounge clear plastic pill bottles, such
as aspirin bottles or small plastic jars. Fill the bottle with the
desiccant (remember to dry the gel first) and then use a double
thickness of coffee filter paper carefully and securely tied around
the neck of the bottle to keep any of it from leaking out (remember
the indicating type of silica gel is not food safe). The paper is
very permeable to moisture so the gel can do its adsorbing, but
it's tight enough not to let the crystals out. I use plain cotton
string for this as both adhesive tapes and rubber bands have a way
of going bad over time which could allow the cap to come off and
the desiccant to spill into the food.
For containers that have openings too narrow to use a desiccant
container such as described above you can make desiccant packets
with the same filter paper. The easiest way I've found to do this
is to wrap at least a double layer of paper around the barrel of
a marker pen and use a thin bead of white glue to seal it with.
Slide the packet off the pen and allow to dry. When ready, fill
with the necessary amount of desiccant. You can then fold the top
over and tie with string or staple closed. Take care that the top
is closed securely enough not to allow any desiccant to leak out.
Virgin (not recycled) brown Kraft paper can be used to make the
packets with as well.
The above method will also work for the other desiccants, subject
to whatever precautions the individual type may have.
IMPORTANT NOTE: The indicating form of silica gel (has small blue
or pink specks in it) is not edible so you want to use care when
putting together your desiccant package to insure that is does not
spill into your food.
WHERE DO I FIND DESICCANTS?
I buy indicating silica gel at Wal-Mart in their dry flower section
where it is sold in one and five pound cans for flower drying. I've
seen it sold the same way in crafts stores and other department
type stores that carry flower-arranging supplies. You can also buy
it from many other businesses already prepackaged in one form or
another to be used as an adsorbent. All of the desiccant that I've
found packaged this way has been rather expensive (to me) so shop
carefully. There are a number of Internet sources available which
will probably provide your best route for finding what you want.
Businesses carrying packaging supplies sometimes also sell desiccants.
Some businesses commonly receive packets or bags of desiccants packaged
along with the products they receive. I've seen Montmorillonite
clay in bags as large as a pound shipped with pianos coming in from
Japan. Small packets of silica gel seem to be packed in nearly everything.
Naturally, any salvaged or recycled desiccant should be of a type
appropriate for use with the product you want to package.
It is possible to make your own desiccants using gypsum from drywall
and maybe Plaster of Paris. Calcium oxide can also be produced from
limestone (calcium carbonate) or slaked or pickling lime (calcium
hydroxide) by roasting to drive off the adsorbed water and carbon
dioxide. I don't have any clear instructions, as of yet, on how
to go about this. Please do keep in mind that calcium oxide (quicklime)
is caustic in nature and is hazardous if handled incorrectly.
Desiccants: Overview
Interest in desiccant products has never been higher than it is
today. IMPAK has more technical knowledge and experience in this
area than anyone. As electronics grow both more complicated and
more portable than ever before, you need a way to protect your sensitive
equipment. However, desiccants are not merely limited to applications
in the electronics field. Any item that can be damaged by moisture
or might need long-term, safe storage can benefit from the proper
use of desiccants.
We understand that you, the consumer, may not necessarily be an
expert in the desiccant field. With that in mind, we have created
these informational pages for you to better understand how to protect
your investments. The information can get highly technical at times,
so if you still have any questions or clarifications, please feel
free to e-mail us....we're
here to help!
SorbentSystems is the online presence of IMPAK Corporation. If
you do not find the information you are looking for on this site,
Tech Support is also available by telephone Monday through Friday
from 8:00 am to 5:00 PM.
Desiccant Types
Besides the indicating silica gel used in the Dri-Box canister,
there are several other desiccant materials in use today. Below
you'll find information on each, with a short summary of strengths
and weaknesses.
Montmorillonite
Clay
Silica
Gel
Indicating
Silica Gel
Molecular
Sieve
Calcium
Oxide
Calcium
Sulfate
Other Adsorbents
Montmorillonite Clay
Montmorillonite clay is a naturally occurring adsorbent created
by the controlled drying of magnesium aluminum silicate of the sub-bentonite
type. This clay will successfully regenerate for repeated use at
very low temperatures without substantial deterioration or swelling.
However, this property causes clay to give up moisture readily back
into the container as temperatures rise.
Clay is a good basic desiccant that works satisfactorily below
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