jgourlay - 27-9-2008 at 10:15
Gents, a warning on the inexpensive faceted alchohol lamps that are currently for sale on some sites. Long story short, they are made from non-lab
grade glass.
The upshot is that after about 5 minutes of use, they become hot enough to cause the glass to crack through. The crack then starts to leak fluid that
immediately catches on fire.
This is really great, especially when (skeptical) mom is watching you teach science to the kids 
Fortunately, it didn't SHATTER until I got it out to the yard to a sandy spot.
panziandi - 27-9-2008 at 10:18
Blimey that could easily have been very much worse! Good warning!
undead_alchemist - 27-9-2008 at 13:13
The better made alcohol laps from one supplier cost $7.00 each list.
jgourlay - 27-9-2008 at 15:15
Undead: what's your source? Also, are those micro butane torches "better".
I'm looking, of course, for the safest source of gentle heat. But I like the alcohol lamp because well, it uses a cheap fuel.
chemkid - 27-9-2008 at 15:25
I have used an alcohol burner for up to twenty consecutive minutes and had no problem. In fact, i could pick it up comfortably with my hands. The wick
on mine has a metal sleeve which elevates the burning to about 2cm above the actual glass.
[Edited on 27-9-2008 by chemkid]
Magpie - 27-9-2008 at 15:27
I've never heard of such a thing. I used an alcohol lamp for years as a kid that came with my Gilbert chemistry set with never a problem. It seems
strange that the glass would even get that hot. It seems like most all the heat would be from the flame cone up. But I haven't used one in a long
time.
ScienceSquirrel - 27-9-2008 at 15:46
I have used alcohol burners in the past with no problems.
Go for a good quality burner for medical use or similar and you should be OK.
Butane torches are OK but they need a high fuel air ratio to ignite.
After that you have to throttle them down to get a cooler flame otherwise they will crack glass.
HydroCarbon - 29-9-2008 at 19:36
I had the same thing happen to me when I was using a cheap alcohol lamp as well. I had it lit for only about 15 minutes, first time using, and I
heard a snap. I didn't know it had cracked until I put it out after hearing the snap and saw the top move. Luckily I had only filled it half way and
the crack was at the very top near the metal cap.
People should definitely watch out for this, as it could be extremely dangerous if a full lamp cracked to spill ignited alcohol all over the place; or
vapor escaping from the crack was ignited.
I got a micro butane burner to replace the alcohol lamp and it works great.
I would like to try one of those wickless alcohol lamps, though, as alcohol is much cheaper to burn than butane.
[Edited on 29-9-2008 by HydroCarbon]