SAFETY IS A PRIORITY, THIS IS AN EXPLOSIVE HYDROCARBON WHICH SHOULD BE USED NEAR THE APPROPRIATE FIRE EQUIPMENT AT ALL TIMES, now that’s out of the way, we can get to the interesting stuff…
Butane. This wonderful, yet under-appreciated chemical with properties that seems to help in almost every field. Let me start by listing a few of its properties: when mixed with oxygen it deflagrates explosively, when in low-oxygen environments it burns with a low flame, it’s a liquid at 0C but rapidly evaporates at anything higher, and when stored as a liquid the pressure is reasonably low, but still enough to keep a can pressurized. These may seem like common features of many common hydrocarbon fuels, however none are as cheap and readily available, yet also safe and useful.
Tip: Always have a 1-2ft long tube of heatshrink attached to the nozzle, so that you are never using the can to apply butane directly. If you have to light the jet, you can hold the tube farther up and control the stream safely without putting your hands near the fire. A nifty side effect of using heat-shrink is that if the flame ever gets too hot, the tip of the tubing will begin to contract and cut off the supply of fuel, effectively putting out the fire that could’ve raged out of control.
Tip: Keep a “bubble” of un-shrunk heat-shrink about 1″ or 2″ away from the tip of your 1-2ft long tube. This can be done by holding a lighter on the very tip for a second, then holding it briefly on a section about 3″ up. This little bubble acts as a temporary reservoir of liquid butane between sprayings, allowing you to dribble out droplets of it, or light the evaporating stream without igniting the full jet.
Here are some of the reasons I always keep a can of Butane handy by the workstation:
1. When un-lit (be careful) it is a very efficient coolant. When hot-gluing a project you can rapidly cool the hot glue by briefly spraying butane on it. Frosting and condensation on the surrounding parts is an unfortunate side-effect, but this can be avoided by spraying in bursts. (another use would be in regenerative cooling in one of my rocket projects)
2. When lit (be even more careful) it provides concentrated bursts of extremely hot flame, useful for localized melting and ignition. When using lit butane, it is always important to remember that the un-lit gasses can build up and explode suddenly when they reach a critical mass. I’ve had a few accidents where I’ve lost most of the hair on my legs this way. Luckily these explosions are scary but rarely do any real damage, as they last milliseconds and very little heat is transferred to surrounding materials.
3. It’s usually stored pressurized and can be used like any other pressurized gas. I personally like to use it whenever my laptop starts to overheat by spraying a long burst of it on the CPU bridge (beware condensation). This also makes for a very nice effect when DJing at parties, as the misty fog rolling off the laptop looks quite awesome. The evaporation cools the laptop, and the pressure dusts off my keyboard nicely. [side note: it can be used to inflate balloons, which–when popped by a lighter–explode with a deafening bang]