By March 8, 2013

Check Your Desiccants

About a year ago I wrote about how to make your own desiccant packs to help stave off rust and moisture-related damage.

I was doing some inventory over the weekend, and it occurred to me to look at the different silica bags I had in each container.

Some of them were getting saturated, and one was definitely past its prime.


Here is plain (not really “clear”) indicating silica. It’s the same Amazing Cat Litter you can buy online or in pet stores, or you can spend over twenty times the amount and get pre-made bags with the same stuff.


This is a partially-saturated bag that I took from a box containing computer components. This came from an ammunition can that had not been opened since sometime in 2011.


I bought this pre-made bag from eBay in 2007. It was also in an ammunition can that had not been opened since 2011. It is mostly saturated.


A bag from the same lot was completely saturated. To me, this shows the effect of opening and closing the cans. Air moisture gets into the can, and the silica degrades more rapidly. I threw away all of the silica packs from the eBay lot.

So, a few lessons learned here:

  • If you’re making your own silica gel desiccant packets it doesn’t make much sense to re-use ones from other products.
  • Check your desiccant packets on a regular basis. “Regular basis” is going to depend on a ton of variables: the size of the container you’re trying to de-humidify, how often you access that container, and the amount of moisture in the storage environment. I’ve decided to check my stocks once a year.
  • Toss any packs when a third or more of the silica indicates that it’s saturated. Again, this threshold may be different for you based on the factors I typed up above. It’s cheaper to replace the packs and not worry, especially when you’re making your own.
Posted in: preparedness

5 Comments on "Check Your Desiccants"

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  1. Desiccants can be recharged by cooking the moisture out of them:

    I’m not sure whether this is news to you, or you just find it not worth the effort, but I figured I’d throw it out there. Scuba divers know this trick well.

  2. DrFaulken says:

    Yep, that’s a very easy thing to do : pour the silica out on a tray, heat it slowly in the oven.

    In my case, I have sixteen pounds of silica in the house, so I am not too interested in reusing it. However, the idea is a good one!

  3. So now I’m intrigued. I need desiccants for my beef jerky… but I have an innate distaste when I think about putting bags of kitty litter in with something I’m going to eat. Is it really pure silica gel? Would you feel comfortable using it for that kind of application? (assuming of course that I seal the bags up properly)

  4. DrFaulken says:

    The product claims to be 100% silica. I would definitely trust it with food. I don’t know if you saw my original review or not :