Before automobiles had electric headlamps, they were equipped with lamps that burned acetylene gas-which was generated by calcium carbide reacting with water. So, after you started the engine, you had to start the headlights-and light them. It sounds dangerous-especially as you had gasoline fumes from the old leaking carbureators. Anyway, were these lamps reasonably bright?
I picked up one of these maybe 25 years ago from REI or some other outdoor outfit. It was great for camping. It lit up the entire campsite, and then some. Never bring it near, nor inside of a tent, though.
Yes. With a proper reflector they give an impressive amount of light.
How safe are they? I see them occasionally for sale and was thinking of getting one for mrAru for his birthday [his grandfather was apparently an authority on hard rock mining and I think it would make an interesting present for him because of that.]
the small amount of gas in a headlamp is created as it is used and/or used as it is created; it is not like having a tank of compressed gas. they are safe enough to use in a mine that might be filled with explosive gases; though that by design of the lamp not because it was acetylene.
Pretty safe if you know what you are doing. I would not use them indoors since a small amount of phosphine or arsine (my memory fails me which one) is produced due to the impurities in the calcium carbide. Also, if the flame goes out, you need to follow proper precautions before relighting it.
If you want to use it in a mine or a cave, it produces a nice illumination - but it is very expensive compared to LED lights. It also produces soot - and may give you black snot and is banned in many caves due to the soot residues. If you suspect that there maybe methane in a mine - dont even think about it.
They are about as safe as anything else with a fuel and an open flame. However, those flames are way hotter than a candle flame so you can get a larger burn faster or more easily accidently set something on fire.
The biggest danger is probably the calcium carbide. You do want to store it properly. And you want to be careful that no gas that is produced is allowed to build up, because an acetlyne/air mixure ignites quite easily. So the calcium carbide needs to be stored in an airtight and watertight container. However, THAT container needs to be stored in larger area than is not particularly airtight so that any gas inavertently produced can’t build up to a dangerous level. No worse than a can of gasoline or a propane bottle or the like. Just don’t be stupid or careless and you’ll be fine.
They do give off a nice light. Great for piddling around the campsite in the evening. Nice hand warmer too. And lighting them the explosive bang way is quite fun. And kids seem to have fun with them as well.
There is a reason they were used by so many for so long. All in all it was the best source of light for certain applications.
Interesting fact about acetalyne. IIRC a volume of acetone can store something like 700 volumes of acetalyne in solution. Also, IIRC acetalyne give off the most visible light per amount of energy used (whereas a hydrogen flame lamp would royally suck). But don’t quote me on these facts, they could be off a bit as the coffee is just now kicking in.
Oh, and don’t just dump the waste material where animals, wild or otherwise, can get to it. Apparently they eat it and it ain’t good for them. Though personally I can’t imagine anything eating that stuff but who knows?
I have seen some in operation on classic motorbikes and they do give a pretty good strong light, much better than the alternatives of the time which would be wick oil lamps. They were fiddly to use. The generated gas fed to a fish tail shaped ceramic channel, a speck of soot made its fine channels inoperable. So best practice was not to turn it off but to stop the gas generation and let it go out as the gas exhaust.
I’ve got a couple acetylene cap lamps around. The light’s not particularly bright, but it’s warm and diffuse, and good enough to find your way around. Caving / miners camp lamps ARE fiddly to use. One reason is that the level control is indirect - you adjust a dripper for the water reservoir in the top part of the lamp, which controls the rate that water drips onto the carbide to make acetylene. That, in turn, determines the flame level. You also have to carry a little retractable wire doodad to clean the nozzle which gets carboned up (most convenient to hang it around your neck inside your coveralls).
Yeah, if you aren’t familiar with them, it’s strangely satisfying to light them the “explosive bang way” - the lamp has little sparker with a flint in it on the edge of the reflector. The technique is to hold your hand over the entire reflector with the edge of your palm against the sparker for a few seconds, allowing acetylene to build up. Then wave your hand away, flicking the sparker. Hopefully, it goes “whoomp” and you have a flame on the front of the thing.
A bonus of having carbide around is for starting campfires in wet conditions - since carbide + water = acetylene gas, put a little container of carbide under your damp firewood, and you are in the novel position of being able to dribble water onto the smoldering fire to get it going.
Oh, and the reaction in question is:
CaC2 + 2 H2O -> C2H2 + Ca(OH)2
Calcium Carbide + water = acetylene + calcium hydroxide, also known as slaked lime. Often, you have extra water, so you wind up with limewater. Not the absolutely worst thing for the environment, but not good for it either.