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16 November 2001

Substitutes for Bunsen Burners

by Shawn Carlson

Bunsen burners are so ubiquitous in chemistry classes that many students think you can't do chemistry without them. Not so. In fact, today's citizen scientist can choose between many convenient sources of heat that will keep your chemical brews bubbling along.

For slow heating needs, I often use a homemade alcohol lamp. These are embarrassingly simple to fabricate from any small glass bottle with a metal lid, and a short piece of clothesline. I suggest you stock up on baby food jars like they are going out of style, because they are. Many companies are now packaging their baby food in square all-plastic containers that will burn your house down if you're foolish enough to light a fire near one.

To fashion your alcohol lamp, punch a hole in the center of your metal lid using a hammer and nail, and thread a few inches of cotton clothesline through to act as a wick. Fill the jar with denatured alcohol (available at any hardware store), replace the lid, let the alcohol wet the wick, then light it. That's all there is too it. Make sure you don't substitute isopropyl (rubbing) alcohol as it produces a sooty smoke that will coat whatever you're heating with a layer of carbon. (I avoid wax candles and oil lamps for the same reason, unless, of course, I need to blacken something.) Also, never never never try to re-fill the lamp while wick is still burning. That may seem obvious, but a good friend and expert citizen scientist I know darn near burned his laboratory down when he tried to save a few seconds by tipping up the lid and squirting a little more alcohol into the jar. The in-rushing fluid drove a whoosh of highly volatile alcohol vapor over the flame and vhoosh, a spectacular fire ball nearly torched his home! So always think safely first.

For Bunsen burner-level BTUs gas camp stoves can't be beat. They use the same gas as Bunsen burners, are completely safe (so long as you follow the normal precautions) and support the weight of just about any container you need to heat. Therefore they act like a Bunsen burner and ring stand for many applications. They also have the benefit of being extremely reliable and quite inexpensive. I prefer a deluxe four-seater model because it lets me heat multiple pieces of glassware simultaneously and can take quite a lot of weight. But the single seaters are also extremely convenient for intense heat over a smaller footprint. Of course, Propane produces carbon monoxide when burned, so make sure your workspace is well ventilated.

Occasionally, I need to heat something extremely fast or at really to high temps. Then I use a brazing torch fed with Mapp gas. Hardware stores stock both for brazing and soldering at a modest cost. It's a mixture of acetylene-propadiene and liquefied petroleum and it burns much hotter than Propane.