Many people like the idea of using a desiccant to protect items from moisture damage, but don't really understand how to do this effectively. Here are some guidelines to help assure you get the maximum results.

What type of desiccant should I use? 

The most commonly used desiccants for this purpose are Silica Gel or Activated Clay.  Silica Gel  Most consumers, or home uses, are geared towards removing moisture from the item itself and the air within a storage container. This would include: Cameras and other electronics; Gun/Rifle Storage Case; Safes/safe deposit box; Time Capsule; Stamp collection; Coin collection; Autograph collection; Comic Books; Shipping/storage of electronic equipment; Overseas shipping; Or any sealed container you wish to keep moisture free.

 

Shown: 5 gram & 10 gram  Silica Gel packets and Moisture-indicating card    

Different sizes are available to best suit your needs.

How much desiccant do I need to do the job? 

This is the most important question you can ask. There is a misconception about desiccants thanks in part to the little packets we find in products we buy, like new shoes. You'll find the little -pillow- inside the shoe box that says something like -do not eat- and we're lead to believe this tiny packet protects this pair of shoes from moisture. NOT TRUE! The volume of the box is about 350 cubic inches and would need about 10 grams of desiccant for the air volume, but the box is made of paper - paper holds moisture and also allows new, moist air to enter. The proper way to protect this same pair of shoes is to use the same 10 grams of desiccant, but protect the shoes inside a non-permeable -plastic- bag or box, sealed against new air. I have included  a simple REQUIREMENT CHART below that will help you determine how much desiccant you need to do the job.

How long will the desiccant last? 

This will depend entirely upon the exposure to -new- air. For example, if you used the correct amount of desiccant in a Time Capsule and opened the capsule in 100 years, the air - and the materials - inside the capsule would be perfectly dry. However, if you opened that same capsule every year to check up on the contents, you would expose the desiccant to moisture upon each opening and when the desiccant became saturated with moisture it would simply quit adsorbing any more.

How do I know if the desiccant is still good? 

It is most practical to enclose a MOISTURE-INDICATING CARD along with the items you are protecting. The card has blue-colored circles that remain blue as long as there is not moisture present. The circles begin to turn pink as they are exposed to moisture. Pink circles indicate it's timeto change your desiccant.

Can I regenerate my desiccant once it has been saturated? 

In many cases, yes. If the desiccant is Silica Gel, or Activated Clay, you can put the packets in a 245 oven for 16 hours to regenerate the desiccant. Although this is not always practical or cost effective, it will produce a product almost like new. There are a couple of exceptions- FLOWER-DRI, used for drying fresh flowers, a very fine silica gel with a moisture indicating chemical built right in, is a loose product - not in packets. You can spread FLOWER-DRI in a thin layer on a cookie sheet and dry in a 245 oven for 2-3 hours, or until the blue moisture-indicator reappears. And, any product packaged in TYVEK - a spun polyolefin fiber used for storage of food items or pharmaceuticals - cannot be regenerated as the TYVEK will not stand up to the heat.

Where can I get desiccant? 

There are many suppliers of desiccants on eBay.  Silica Gel   desiccant

REQUIREMENT CHART          
Container Size         
Gallons      Cubic Ft.    Cubic In.    Grams of Desiccant

1.1      or     0.14    or     237           Grams needed =  5 
2.1      or     0.28    or     476           Grams needed =  10 
3.2      or     0.42    or     714           Grams needed =  15 
6.2      or     0.83    or     1,428        Grams needed =  30 
12.5    or     1.67    or     2,856        Grams needed =  45 
18.7    or     2.5      or     4,284        Grams needed =  60 
25       or     3.33    or     5,712        Grams needed =  90 
37.4    or     5         or     8,568        Grams needed =  135 
50       or     6.66    or     11,424      Grams needed =  180 

This chart does not consider the materials being used for packing, etc., but it is a start and will give you an idea of what size desiccant packets to use and how much desiccant to buy for your purpose.