Author Topic: author with a question on carbide lamps  (Read 1049 times)

Offline marethgriffith

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author with a question on carbide lamps
« on: October 11, 2018, 06:32:14 am »
Hello,

I'm an Alaska-bases author, doing some research on a steampunk book I'm writing that involves characters working with carbide lamps.

My question is - if you took a lit carbide lamp and threw it into a puddle had enough to (a) crack the lamp and (b) allow water to soak the carbide reservoir all at once - what would happen? It seems like the lamp has enough outlet valves that it wouldn't actually explode - just have huge flames shooting out of the tip and maybe all around the gasket?
And how long would a fairly full lamp in this configuration burn before all the calcium carbide was exhausted? Ten minutes? More?  Less?

Has anyone had this happen, or heard any stories of this happening? Or want to

Thanks in advance for your assistance!

Offline Groundhog

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Re: author with a question on carbide lamps
« Reply #1 on: October 11, 2018, 09:36:51 am »
Hi.
This is a very unlikely scenario. In 50 years of caving it has never happened to me either with the old brass Premier or in later years with an Arian generator. In our irresponsible youth we would often deliberately make carbide bombs but I can't remember how we did it.
The old Premier would sometimes leak from the seal but all that would happen was a few small flames before the lamp went out.
I was once in a tiny chamber half full of water when my carbide tin fell out of my pocket and the lid came off. The chamber immediately filled with acetylene but fortunately my lamp had gone out and I didn't try to relight it. God knows what would have happened if I had.
If you're curious just get some carbide and mess about with it. With care of course!

Offline GoneCaving

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Re: author with a question on carbide lamps
« Reply #2 on: October 11, 2018, 11:04:30 am »
The nearest I've seen was with the Stella carbide lamp in self-pressurising mode (gas used to pressurise the water reservoir). Get that one running too hot leads to a build up of pressure, some very impressive flames for a while, and then usually a loud pop as the ceramic jet in the headlamp gets fired off into the distance. Thankfully no explosions.

Offline Wolfo

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Re: author with a question on carbide lamps
« Reply #3 on: October 11, 2018, 11:14:50 am »
Once blew up one of my cave stuff drums.
After some aid climb trip in a cave I stuffed the "cold" carbide lamp (still a minimal bit of carbide left, as i learned later...) and oversuit into the drum and we drove to our campground.
Well...wanted to wash the oversuit in a nearby stream, opened the drum - BOOOOM.
Likely static electricity from the oversuit cordura material caused the iginition + the rare luck of a critical acetylen - oxygen mixture in the drum.

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Offline Fulk

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Re: author with a question on carbide lamps
« Reply #4 on: October 11, 2018, 12:06:22 pm »
I think that I'm right in stating that acetylene doesn't actually need a spark to ignite it – it becomes spontaneoulsy unstable and liable to explode under even modest pressure, such as that that could be generated in a sealed ammo box (or modern equivalent), for example, by an extiguished lamp still giving off a bit of gas.

Also I would guess that the explosion limits of a mixture of acetylene and oxygen are quite wide, so not so 'rare'.

Offline droid

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Re: author with a question on carbide lamps
« Reply #5 on: October 11, 2018, 12:16:19 pm »
I seem to recall that wading with a remote generator under water tended to increase the intensity of the flame....

Mind, that was bloody years ago.
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Offline PeteHall

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Re: author with a question on carbide lamps
« Reply #6 on: October 11, 2018, 12:39:04 pm »
In our irresponsible youth we would often deliberately make carbide bombs but I can't remember how we did it.

Plastic pop bottle with a pin-hole in...  :thumbsup:

In an attempt to answer the original question, I think most generators are pretty tough and you'd struggle to crack one by throwing it on the ground. If it did split right in half and all the carbide came out, this would be similar to tipping out the contents into a puddle which I have done (an easier option than leaving the headset dangling out of the window while driving home).

This fizzes and pops quite enthusiastically (depending on the amount of carbide) and gives a good light show if you ignite it. As it burns down, after a few minutes, the pops often put out the flame, so you need to red-light it.

In the scenario described above, I think the lamp would probably go out as it was thrown, so I imagine it would be unlikely to self ignite, unless there was another source of ignition very close by.

If the generator cracked to let water in, but with carbide still inside, you could probably ignite a flame at the crack, which could burn for some time, but I doubt you'd replicate the "carbide bomb" effect as there would be no oxygen inside...
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Online Kenilworth

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Re: author with a question on carbide lamps
« Reply #7 on: October 11, 2018, 12:42:47 pm »
For big loud sound tie up carbide and water in a large inflated garbage bag and toss in the fire.
Nothing spectacular will happen if you throw a cracked light into a puddle.

Offline Duncan Price

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Re: author with a question on carbide lamps
« Reply #8 on: October 11, 2018, 01:38:25 pm »
I think that I'm right in stating that acetylene doesn't actually need a spark to ignite it – it becomes spontaneoulsy unstable and liable to explode under even modest pressure, such as that that could be generated in a sealed ammo box (or modern equivalent), for example, by an extiguished lamp still giving off a bit of gas.

Also I would guess that the explosion limits of a mixture of acetylene and oxygen are quite wide, so not so 'rare'.

Acetylene can spontaneously decompose above 2 bar.  Acetylene cylinders for welding contain the gas dissolved in acetone under pressure.

Acetylene generated from calcium carbide can contain small amounts of diphosphane (P2H4) from the presence of a calcium phosphide impurity.  This is pyrophoric and can catch fire on exposure to oxygen igniting the acetylene.  The Lower Explosive limit for acetylene is 2.5% wv/v in air.  Lower than a lot of gases people normally get twitchy about (e.g. hydrogen) though not a low as petrol vapour.  Though you do normally need an ignition source to set it off.

Offline tony from suffolk

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Re: author with a question on carbide lamps
« Reply #9 on: October 11, 2018, 05:16:05 pm »
I think that I'm right in stating that acetylene doesn't actually need a spark to ignite it – it becomes spontaneoulsy unstable and liable to explode under even modest pressure, such as that that could be generated in a sealed ammo box (or modern equivalent), for example, by an extiguished lamp still giving off a bit of gas.

Also I would guess that the explosion limits of a mixture of acetylene and oxygen are quite wide, so not so 'rare'.
Indeed. I was on the way to a Short Round Trip in Swildon's, carrying an ammo tin containing a spare Premier carbide, & slung round my back. As I jumped down from the drop at the bottom of the old “Forty”, the box knocked against the rock and then exploded with a loud bang, throwing me across the chamber. It took me a while to realise what had happened! Fortunately, I suffered nothing more than a few bruises, but the ammo tin's lid was bent up at right-angles, the box itself blown into a rounded shape.
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Offline Tripod

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Re: author with a question on carbide lamps
« Reply #10 on: October 12, 2018, 04:48:36 pm »
As a lad I knew, from somewhere, about making "bombs" with a bottle (all glass in those days), carbide and water. For my first experiment I used a Dettol bottle (small, disinfectant bottle), put carbide and water in it and tossed it into a brook. Fear then took over as instead of being carried quickly away the bottle just dawdled along. Nothing happened and the bottle stopped in a wide, still section of the brook, fortunately as it turned out, some distance downstream. Disappointed from a long delay without any action my friend and I stood there - then there was a bang and the water erupted. As the ripples settled the top of the bottle came down from what must have been a considerable height. Lesson learned, carbide is dangerous, take care with future experiments. Subsequent silliness after I started caving a few years further on did not match that first experience. 

Offline Simon Wilson

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Re: author with a question on carbide lamps
« Reply #11 on: October 12, 2018, 06:36:46 pm »
When I was a lad I heard a story from a reliable source that he and his mates used to catch fish in the canal by using carbide bombs. He told me that you had to use the glass pop (soft drink in Canada) bottles with stone tops. By that time pop bottles had pressed aluminium caps. I tried it but the cap blew off with a disappointing phutt.

Years later I was on an expedition to Spain and saw a PET pop bottle for the first time. I was fascinated by these new bottles and how strong they were. We liked KAS Orange so had a good supply of the bottles and also had an ample supply of carbide so naturally I started to wonder. I now know that a PET bottle can hold an impressive pressure and well over the 2 bar mentioned by Duncan Price.

My first attempts failed because I was too timid to keep hold of the bottle long enough to screw the cap on really tight and the cap leaked. The next day I was a bit more determined and screwed the top on as tight as I could. I couldn't hear it leaking like the others but I didn't want to get too close and I was right not to. I got fed up of waiting and went back into the hut. Then there was an almighty bang which echoed off the surrounding cliffs.

Offline Groundhog

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Re: author with a question on carbide lamps
« Reply #12 on: October 12, 2018, 07:05:53 pm »
I've remembered now that we used to put a bit of carbide and water into a narrow necked bottle and quickly pop a balloon over the neck. Once inflated we would hold the balloon over a candle and an impressive fire ball would be produced.
I'm starting to wish I still had some carbide to mess with!

Offline PeteHall

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Re: author with a question on carbide lamps
« Reply #13 on: October 12, 2018, 07:17:18 pm »
We used to put a pin hole in the side of a plastic milk carton, about a third of the way up, put in half an inch of water in, drop in a piece of carbide and light the jet of oxy-acetalene coming out the hole.
This burned like a carbide lamp for a few seconds, before the plastic melted, the flame drew back inside and the whole thing went boom!

I'm looking at an empty milk carton now, and I have a big tub of carbide in the garage, but I doubt my neighbours would appreciate it if I give in to temptation...
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Offline Fulk

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Re: author with a question on carbide lamps
« Reply #14 on: October 13, 2018, 10:25:05 am »
To expand on this topic a bit, ‘when I were a lad’ it wasn’t totally unknown for youngsters to mess about with home-made bombs. The really adventurous would mix sodium chlorate and sugar to produce a really lethal mixture, but the more timid, such as me, would stick to home-made gunpowder. Indeed, when I went to university I met a guy who had only 3 digits on one hand, as a result of messing with chlorate and sugar (oddly enough, he was also a caver, and we met through the caving club). I wonder what sort of reaction you’d get these days if you went into a purveyor of chemicals and asked for sulphur, potassium nitrate and charcoal? Probably a trip to the local nick.

Anyway, we’d scrounge things like cigar tubes and stuff them full of ‘gunpowder’, with some sort of primitive fuse attached, and blow them up. I remember once blowing up a wasps’ nest in a public park (I don’t know why, I guess we must have thought that it seemed like a good idea at the time); it sure pissed off the wasps! (those who survived, anyway).

My bomb-making activities came to an end when we were mixing gunpowder in a friend’s cellar, and we somehow managed to ignite a batch of about a pound or so; fortunately for us, it was pretty low-grade stuff and, out in the open and not compressed, it burned like hell instead of exploding. But even now, many years later, I can remember cowering in a corner, hands over our heads as the place filled up with a thick, impenetrable fog of foul-smelling sulphurous fumes as we waited for it to blow up. I think we learnt a lesson from that!

Offline Duncan Price

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Re: author with a question on carbide lamps
« Reply #15 on: October 13, 2018, 10:56:10 am »
I now know that a PET bottle can hold an impressive pressure and well over the 2 bar mentioned by Duncan Price.

They'll go to at least 6 bar.  I've played around with them to make water rockets:

To expand on this topic a bit, ‘when I were a lad’ it wasn’t totally unknown for youngsters to mess about with home-made bombs. The really adventurous would mix sodium chlorate and sugar to produce a really lethal mixture, but the more timid, such as me, would stick to home-made gunpowder.

Been there, done that, attended A&E.  No lasting scars except an inability to grow a full beard.  Pursued a career in chemistry as a consequence.

I wonder what sort of reaction you’d get these days if you went into a purveyor of chemicals and asked for sulphur, potassium nitrate and charcoal? Probably a trip to the local nick.

All readily available from your garden centre or by mail order - as they have legitimate uses such as greenhouse fumigant, tree stump killer and for BBQ's.  Sodium chlorate (weed killer) is no longer sold under EU regulations as it is bad for the environment.

You can get into serious trouble with plod making homemade stuff and will scupper your chances of ever getting a licence to use the proper stuff for caving.  I was particularly lucky not to lose my eyesight.  A school friend of mine almost blew off his hand.  Cavers have died. :(
 

Offline smilner

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Re: author with a question on carbide lamps
« Reply #16 on: October 13, 2018, 11:14:32 am »
1983 ... a stinky left in an ammo can left overnight.  All was good until someone picked it up and it spontaneously blew up:

Offline Dickie

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Re: author with a question on carbide lamps
« Reply #17 on: October 14, 2018, 02:53:22 am »
Get a large pressurised garden sprayer, add carbide and water and then light the spray nozzle - instant flamethrower!

Things to do when we were bored in the Eldon hostel!

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Offline tony from suffolk

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Re: author with a question on carbide lamps
« Reply #18 on: October 14, 2018, 03:12:54 pm »
1983 ... a stinky left in an ammo can left overnight.  All was good until someone picked it up and it spontaneously blew up:
That looks hauntingly familiar.
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