How often do you replace silica gel?

[lucaspalm]

Hi,

I have a simple question about silica gel / moisture absorbers used for storing camera gear.

How often do you usually replace or regenerate them?

Is it based on time, color indicator, or storage conditions?

Just asking for general practice.

Thanks.

[Les Olson]

Silica gel only absorbs about 25% of its own weight in water. At 30 degrees C, the maximum water capacity of air is about 30g per kg and the density of air is 1.22 kg/m3. So if you have 0.1 m3 of storage to protect, you need to absorb 0.122 x 30 = 3.7 g of water, so you need 15 g of silica gel.

I use a dry cabinet. It is much more effective and cheaper in the long run.

[David H. Hartman]

Most silica gel beads have indicator beads, frequently blue when the silica gel is dry and ready to use. I bake silica gel at the lowest heat my kitchen oven offers.

Best,

Dave