Dessicant Silica Gel

  Covergirl 12:20 11 Aug 2010
Locked

You know, the stuff you get in little bags with your electrical goods etc.

I just wondered how one was supposed to tell when it needs to be "recharged" i.e. has reached saturation point and needs to be dried out?

(I got a fairly large bag the other day,maybe as much as an ounce, and thought I'd put it in my box of seeds for next year.

Thanks.

  wiz-king 12:22 11 Aug 2010

It usually contains an indicator and changes colour from blue to pink when it needs regenerating.

  john bunyan 12:32 11 Aug 2010

When we used it in certain diving equipment, we had a phrase "When it's new, it's blue" as wiz-king says it goes pink when saturated. You could try drying it (carefully) in an oven, but take further advice re temperatures!

  Covergirl 12:35 11 Aug 2010

thanks for the speedy answer w-k.

I must admit I've never noticed an indicator, and to be truthful, most of these baggies are only a little larger than the size of a packet of cafe salt portion so I can't see an indicator being cost effective on the short life of one of these which would just get binned by the recipient anyway.

I will have a look later. Maybe it is the printing on the bag . . . ?

  Covergirl 12:36 11 Aug 2010

Yes, I'll have to check the bag!

For gentle drying of anything, I usually put them on the back of the telly or on top of the PC monitor. Not so easy now everything is flat panel! Ha!

  john bunyan 13:33 11 Aug 2010
  morddwyd 16:38 11 Aug 2010

Unless they have re-activation instructions on them, the ones you get in electrical goods etc. are not really designed to be "rechargeable" anyway, and you would not know how long to do them for or at what temperature.

You could try overnight in the airing cupboard, but you'll never know how successful you've been.

  BT 16:46 11 Aug 2010

You only tend to get indicator in Laboratory supplies of Silica Gel to be used in Dessicators.
The little bags you get in packaging can be dried quite easily by putting in a fairly warm place - even on top of a radiator. The temperature is not too critical, we used to use a Lab oven at about 110c at work.

  Bald Eagle 19:19 11 Aug 2010

As a trained industrial chemist of 50 years experience. These small bags will be "dry" in a couple of hours at 110 celcius. The trouble is that, if non indicating, you will not know when they need redrying.

  Quickbeam 07:36 12 Aug 2010

I've always just binned them when I open the box, and considered that they're only intended for the life of the products shipping journey.

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