Using silica gel for storage

[Rider]

I understand that lenses and other gear can be damaged by excess humidity, so I've tried to find a source for silica gel. I've found some on e bay, but given that silica gel by its nature is only good when it's fresh, I'm reluctant to spend money and not have the results I intended. Does anyone else use silica gel to reduce humidity for photo gear storage, and where do you get the stuff from? Is there a better material/method for storage?

[IanG]

You can dry it out again and its as good as new. Just put it on a radiator. When I ran a lab we just put it in an oven.

Ian

[Ron Marshall]

I understand that lenses and other gear can be damaged by excess humidity, so I've tried to find a source for silica gel. I've found some on e bay, but given that silica gel by its nature is only good when it's fresh, I'm reluctant to spend money and not have the results I intended. Does anyone else use silica gel to reduce humidity for photo gear storage, and where do you get the stuff from? Is there a better material/method for storage?

Regenerate in a 250 F oven for 3 hours:

http://www.sportsmansguide.com/net/cb/cb.aspx?a=359233

[Ash]

I'm starting to. I nabbed a bunch of those mini sachets that you find in clothing and leather goods, as I had a few enlarger lenses get hit by damp and fungus when left in the darkroom/shed. I'll check on them in a few days and see what they're like.

I believe desiccants only really work when they are in a fairly sealed environment, otherwise it will attract moisture, rather than draw it away from the more valuable material. Try using sealed bags as well.

[Kevin Crisp]

I use the small ones with the aluminum case and the little window that shows blue when fresh, pink when exhausted. I have a ton of them, I dry them all out in the oven at 250 for about 3 hours then keep them in airtight storage until I need them. doing them all at once saves energy. Toaster ovens work well for this if you have a small quantity, they dry out faster than 3 hours that way. It seems impossible to wear then out, some are 12 years old and work fine. There is also a plastic version made for microwaving which is faster but the plastic eventually cracks. Amazing how much water comes out in the microwave with the plastic ones, it shows you they work.

[GPS]

-snip
I believe desiccants only really work when they are in a fairly sealed environment, otherwise it will attract moisture, rather than draw it away from the more valuable material. Try using sealed bags as well.
They work better in a sealed environment because once the humidity is chemically taken on their surface they made the air dry and keep it as such. Don't be afffraid of them -in no way could they harm -even fully charged with humidity, i.e. exhausted in their drying effect - "the more valuable material" by giving off humidity. That is only possible if heated at 250°F... And if they are in a non sealed environment, it's not their fault either that humidity has its effect on the "valuable material".

[GPS]

I used to buy silica in greater amount and put them to the 35mm film containers with drilled holes and fine mesh pockets. Worked well and I found some use for the containers...

[cyrus]

I understand that lenses and other gear can be damaged by excess humidity, so I've tried to find a source for silica gel. I've found some on e bay, but given that silica gel by its nature is only good when it's fresh, I'm reluctant to spend money and not have the results I intended. Does anyone else use silica gel to reduce humidity for photo gear storage, and where do you get the stuff from? Is there a better material/method for storage?

Silica is only useful in sealed environments. It quickly absorbs humidity, and becomes useless. You can heat it up to drive out the humidity, but then you'd have to quickly place it in a sealed environment.

[GPS]

Silica is only useful in sealed environments. It quickly absorbs humidity, and becomes useless. You can heat it up to drive out the humidity, but then you'd have to quickly place it in a sealed environment.

As all desiccants... Always better than keeping a dehumidifier on to lower the humidity of a room in order to keep the photographica dry, IMHO.

[aduncanson]

As all desiccants... Always better than keeping a dehumidifier on to lower the humidity of a room in order to keep the photographica dry, IMHO.


GPS Please,

What is your argument against using a dehumidifier?

Thanks

[GPS]

GPS Please,

What is your argument against using a dehumidifier?

Thanks

Dehumidifier -I meant the electrical appliance used to make a room dry... hence...

[aduncanson]

Sorry, I 'm struggling here. Hence what?

I have installed a large dehumidifier in my formerly damp basement. An air purifier then pumps filtered, dry air into my darkroom. This way the darkroom stays dust free and the whole basement is protected from mildew. Is there a down side (other than the investment) which I am not seeing?

[GPS]

When using a dehumidifier, you have to keep the opposite strategy than the one with desiccants. The boxes with lenses should be kept open, or the dehumidifier doesn't make too much sense for them. All the space must be open to allow the air exchange. If the room is by its nature humid, that is (otherwise you wouldn't need to dehumidify it.) So surely - the investment, the constant energy needed to keep it dry and dust free too, available in the open boxes, the noise of the dehumidifier...
A desiccant in a closed box is cheap, no need to filter the air for dust etc. On the other hand you cannot dehumidify a room with desiccant, that's clear. Whatever you prefer.

[Rider]

This has all been immensely helpful. I would have never known that silica gel can be rejuvenated.

I have a bunch of old silica gel packets from various electronic equipment. Can those be microwaved as well, or should I buy new stuff?

[Peter De Smidt]

You can rejuvenate the old stuff.

[Rider]

I use the small ones with the aluminum case and the little window that shows blue when fresh, pink when exhausted. I have a ton of them, I dry them all out in the oven at 250 for about 3 hours then keep them in airtight storage until I need them. doing them all at once saves energy. Toaster ovens work well for this if you have a small quantity, they dry out faster than 3 hours that way. It seems impossible to wear then out, some are 12 years old and work fine. There is also a plastic version made for microwaving which is faster but the plastic eventually cracks. Amazing how much water comes out in the microwave with the plastic ones, it shows you they work.

I am looking for those; haven't found them yet.

[Nathan Potter]

Dessicants and dehumidifiers both have their place. I use a dehumidifier in my basement darkroom to bring Austins 90% humidity down to about 35 to 50%. Such dehumidifiers are useful when you have an unsealed environment - say a small room where the air is exchanged frequently with a cooling unit. The dehumidifier continuously extracts moisture from the incoming new air.

Dessicants, silica gel, drierite, etc. on the other hand are useful in a sealed small enclosure with a water vapor capacity that can be completely absorbed by the volume of dessicant used. For long term storage the container must be pretty much hermetic. BTW the ultimate relative humidity in a sealed container with sufficient dessicant will be 2 to 4% so some moisture absorbent plastics could be adversely affected by such low humidity over long time periods.

Nate Potter, Austin TX.

[Rider]

Ron, as far as I can tell, these guys are selling a big bucket of the silica gel. I'm hoping to find it already packaged in smaller packages that are color-coded to tell you when it needs to be rejuvenated. Any ideas where to find that?


Regenerate in a 250 F oven for 3 hours:

http://www.sportsmansguide.com/net/cb/cb.aspx?a=359233

[Mike Castles]

Try Light Impressions, they used to sell the metal containers with silica in them.

Edit...does not say it is silica but these (http://www.lightimpressionsdirect.com/item.action?itemGroupId=28) might work

[Nathan Potter]

One source of silica gel is from dried flower preservationists and collectors. The flower is set in silica gel in a natural position then more gel is added, very carefully surrounding each petal. All this in a sealed can of course. I think there must be a dried flower arranging supplier somewhere on line that sells the stuff.

Nate Potter, Austin TX.