How to Make a Desiccator Bag

About: NurdRage is a dedicate group of science nerds trying to further amateur science with direct how-to instructions in video format. We saw what was already online and we thought "we could do better".....

In this video we make 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.

Unfortunately, this cannot be used for drying liquids.



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    5 Discussions


    9 years ago on Introduction

    If the thing you want to dry is sodium hydroxide, do you just have to heat it or is silica gel more hygroscopic?


    9 years ago on Introduction

    Excellent, I'll have to try this with my sodium chlorate solution that has stayed a liquid for over a month.

    Mike sr

    9 years ago on Introduction

    Crystal cat litter (NOT the clay type) is silica gel. Cheap & easy to get.
    Roast it at @250 F for an hour or two to recycle it.