Understanding how an aerosol can works is important in understanding aerosol can propellants and their purpose. Aerosol cans are a dispersal system that relies on internal pressure to propel the product out of the can in the form of an aerosol.

Aerosol cans typically consist of some variation of these four components:

The container The valve        Mounting cup          Stem          Gasket          Spring          Housing The actuator The dip tube

Now you know what an aerosol is, you can see what an aerosol can is all about: it's a mechanism designed to turn a liquid, such as paint or polish, into a finely dispersed mist. So how does it work?

If you've ever read the back of an aerosol can, you'll have noticed messages such as "pressurized container" and "contents stored under pressure." What's that all about? To ensure that something like paint comes out evenly when you press the button on the top of an aerosol can, the manufacturers have to squeeze the contents inside with a pump or compressor (a bit like inflating a bicycle tire). Typically, the contents of an aerosol are stored at 2–8 times normal atmospheric pressure (and usually the lower end of that range). That's why aerosols really rush out when you press their buttons.

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The container is pressurized so that when the actuator is pressed, the product within the can is pushed through the dip tube and outward from the nozzle in the form of a fine mist or aerosol.