Compressed air is a common tool used in offices and homes all over the world. A very effective tool for blowing away loose dust and dirt that collects on both desktop and laptop computer keyboards, fans, cooling fins, and a multitude of other electronic devices. In fact, it is so common that most people simply use it without thinking twice.
The other day I was in my office helping a client when a friendly neighbor stopped by to borrow a can of compressed air. I had a spare can sitting right on my work bench. Assuring me he would bring back a new replacement he headed for the door and began shaking the can. I told him it was no hurry but he shouldn’t shake the can. Both my client and the friendly neighbor said in unison, “I thought you were supposed to shake it!”.
I quickly explained that most cans with a compressed propellant are intended to expel a product that has a tendency to settle in the can. Therefore shaking the can stirs the product and then the propellant is part of this mixture, insuring the product is expelled instead of just the propellant. However, compressed air is different because the product being expelled is actually the gaseous form of the propellant itself. When shaken, the liquid propellant can foam up and the liquid is expelled with the gas. If the liquid comes in contact with skin it can cause frostbite. The liquid propellant can also be expelled if the can is tilted too far or tipped upside down. When liquid is expelled it detracts from the effectiveness of the product by reducing the amount and pressure of the gas. Furthermore, this significantly reduces the lifespan of the compressed air can as the liquid is the concentrated form of the gas.
Additionally, if used for extended periods, the gas being forced out of the nozzle will cause freezing. By using shorter bursts you can get more efficient use out of your compressed air. My favorite tactic is to use 2 cans a little bit instead of just 1 can a whole bunch. Once the first can starts to get cold and the air flow starts to slow down I switch to the second can.