By far the best choice for a glass blaster is a pressure pot system. This type of blaster has a steel-welded container, usually round, that holds the abrasive. This container can be free-standing or mounted underneath the blasting cabinet. In general terms, it has an opening on the top for filling abrasive into the container, as well as a stopper with a seal, which assures the containment of the abrasive once set under pressure.
It also has an opening at the bottom of the container with an attached valve that allows the air and abrasive mixtures to be introduced into a hose that goes into your cabinet. With this valve, you can regulate how much abrasive gets into the airstream, which is important in executing various techniques of blasting.
Since the abrasive is set under pressure in the pot, much less air is required to operate the pressure system than the siphon system. As a result, you can get away with a slightly less powerful compressor (even though I don’t recommend that), but more importantly, you can use a much smaller nozzle on your blaster. You also do not need to hold a heavy hand piece, but rather blast with a smaller, flexible hose inside your cabinet that only wields a hose barb, a nozzle cap, and the nozzle, making blasting a lot easier on your hands.
To top the ease of operation off, the pressure system nowadays is operated by an attached foot pedal, which makes the on/off function of the whole system a breeze.
—Ruth Dobbins, Professional Glass Consultants