silica gel desiccant packs?

[rappersdelight]

is there a moisture absorbing pack that indicates the absorbing elements inside are spent and no longer working?

[Steve Goldstein]

If you mean the little paper/plastic ones that come packed with lenses and other camera gear, I've never seen one with this feature.

I have a few small metal tins of silica gel that have an indicator window. These can be "recharged" by heating them in the oven. I think I got them from Micro-Mark. They're useful in small tightly closed spaces like a Pelican case.

If you have a larger enclosure, like a safe, you can get a product called "Damp Proof" (there are others) in boating supply stores; West Marine comes to mind. It's a special plastic container with an internal screen into which you dump Calcium Chloride beads. The chemical sucks moisture out of the air; this slows dissolves some of the chemical and the solution drips into to the bottom of the container. You have to dump the liquid periodically, and ocasionally replace the chemical as it is consumed while doing its job. This stuff is used by boaters to keep the below-decks space from getting musty when the boat is closed up. The smallest available package is fine for a safe.

[rappersdelight]

thanks steve. it looks like the silica gel in a tin is what i need...
although if someone made the little packs with an indicator, it would be nice...

[Ron Marshall]

The small aluminum cased silica gel has an indicator window:

http://www.silicagelpackets.com/

[shmoo]

DampRid also makes the silica gel packs. They turn color when they are spent. You can get them at Bed, Bath and Beyond and some drug stores.

[Drew Wiley]

When I travel in very wet climates or am doing something nuts like photographing
right under a waterfall, I carry a tighly sealed tupperware container wrapped with
plastic tape, with indicator gel inside. If a lens gets fogged up, I seal it within this
container until it clears - usually several days. I've salvaged many potentially expensive lens disasters this way. When the silica gel is exhusted, it can simply be baked to recharge it, or inexpensively replaced. I think I got mine from Light Impressions, but there are many sources. Silica gel is good for small objects like
lenses, but not for larger areas like a vault, where Dri-Out or Damp-Rid are more
practical.

[GPS]

Beside the true color changing silica gel already mentioned (blue colored?) even "normal" silica gel pellets change their color when saturated. They start to get a yellowish tint.

[bigben]

I'd stay away from the "blue colored" indicating silica gel as apparently it isn't good stuff to come in contact with. In the UK they actually list the BLUE silica gel as a "hazardous material" and to be disposed of as so. No regulations against it in US, but warn it could could cause cancer.

So make sure you get the white non-indicating or the orange indicating silica gel, just my 2 cents.

Correct me if I am wrong, but Damp-Rid is not silica gel. It is a use once and throw away item (I could be wrong, but if I remember correctly it is just use once approach). So Silica Gel might be a more practical solution, as you can buy a Dehumidifier Box or the Canisters from the SilicaGelPackets.com link provided above and reactivate them as needed. This would allow you to reuse, instead of throw it away!

[mcd]

The best that I have found:

http://www.sorbentsystems.com/desicc...-box_appl.html

Easy to work with, easy to recharge in a microwave oven in a few minutes, self contained.

[Sevo]

I'd stay away from the "blue colored" indicating silica gel as apparently it isn't good stuff to come in contact with. In the UK they actually list the BLUE silica gel as a "hazardous material" and to be disposed of as so. No regulations against it in US, but warn it could could cause cancer.

It contains cobalt chloride in PPM concentrations. If you don't make a habit of eating it, using it for cameras is as harmless as having a oil painting hanging in your living room. It has been regulated because workers on packaging lines handling it by tons a day are permanently exposed to amounts of dust which could in the long term exceed safe levels.

Sevo