How To: Make a desiccator bag for drying chemicals

Make a desiccator bag for drying chemicals

Watch this science video tutorial from Nurd Rage on how to make a desiccator bag for drying chemicals with Dr. Lithium.

The complete guide to making a desiccator bag for thoroughly drying hygroscopic chemicals. Some chemicals are hygroscopic, meaning they absorb water from the air and become moist, mushy, or even liquefy. For highly accurate work and good results in experiments the chemicals should be dried before use. A laboratory device for doing this is called a desiccator.

Laboratory desiccators use vacuum and drying agents. A simple home desiccator can be made from an airtight resealable plastic bag and a hygroscopic drying agent like sodium hydroxide.

Simply get a plastic container and fill it up with sodium hydroxide, then place it inside the bag along with a container of the chemical you intend to dry. Seal it up and wait.

Thorough drying can take weeks. Sometimes you might run into the problem where the top dries before the bottom, you'll have to grind your chemical every so often to continue drying.

The bag is also good for storing already dry chemicals to keep them dry. After using a chemical, return the unused portion to the bag to dry out the tiny bit of humidity it absorbed while you were working it.

Other drying agents you can use are:
Potassium hydroxide
Calcium chloride
Silica gel
Sodium sulfate
Magnesium sulfate
Calcium sulfate
Molecular sieves
Sulfuric acid

Don't use glass because the agents might dissolve the glass. Plastic container are cheap and disposable.

This desiccator only works on solids, it does not work on liquids and cannot be used for concentrating acids, peroxide or drying alcohols.

Brought to you by one of WonderHowTo's favorite scientists, NurdRage.

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