The Veiled Chameleon: April 2005: What not to do with a can of compressed air

What not to do with a can of compressed air

So I'm cleaning out an air filter and, being the thrifty individual (cheapskate) that I am, I get the idea that blowing the dust out of the dirty filter will allow me to use it for a few months longer. Thus, I head for my can of Dust Off - that "compressed air" that is typically used for blowing out computers when they've been opened for the first time in two years.

Now the instructions on the Dust Off label says to "pull trigger in a series of short blasts". That's code for: if you really want something accomplished and thus you need to get a sustained release of air at high pressure for more than a couple of seconds, then this isn't the product for you. Basically, they're telling you not to expect much. I rarely use this "short blast" method, and the task at hand surely wasn't going to be accomplished in that manner.

So I press and hold the trigger of a just opened can until it grows cold, ice forms at the end of its straw, and it scarcely continues to make any wind at all. I've been there before...many times. One method of dealing with this is to run the can under hot water until it gets back to room temperature. This restores the pressure to the inside of the can, and further it allows the liquid inside (whatever it is) to achieve its boiling point when the pressure drops upon pulling the trigger (that's where the "air" comes from). But I don't think that I've ever done that using quite so full of a can as I did today.

After a few brief moments of running it under the hot water, and before I'd expected the can to be warmed back up and ready again to go, suddenly I heard a loud *POP* and I felt a "hit" to the can that actually hurt my hand. I looked over and noticed that the top was suddenly higher than it had been before:

I'm feeling kind of lucky that the welded seams didn't break. It probably wouldn't have been that big of a deal, unless a lot of the liquid managed to blast out all over my skin and do damage, but it sure gave me a shock.

Whether it was intended to, or not, that little fold around the top of the can acted as a bit of a pressure relief valve which increased the volume of the can a bit to decrease the pressure. Kinda cool.

I think that, from now on, when I need more pressure immediately I'll just open a new can and let the old one resume room temperature in its own sweet time.