Urban myth or what?

[Biker]

Hmm perhaps the title of this thread should be woodlore myth


I've just been reading a thread about the best technique for starting a camp fire in the snow and I was reminded of something I read or heard somewhere.

You know that steroetypical image of putting a ring of stones around a fire? Well I'm sure there's a warning that you shouldn't use stones that have come from a stream or at least been submerged as they could explode.

Has anyone ever had first hand experience of this phenomenon?

Yes basic safety would dictate you shouldn't, if there's a slight risk but just how likely is it of ever happening? 1 chance in 10 or about as rare as seeing Elvis crash a UFO into the head of the Loch ness monster?

Thanks for reading.

Biker

 

[PRKL]

ive seen those splitting and cracking,especially when someone has poured cool liquid like water on top of them.usually if the rock is smooth,rounded and like complete,it might crack into pieces but its not like "exploding".so i usually use already cracked crude stones in fire rings.

 

[robin wood]

I've just been reading a thread about the best technique for starting a camp fire in the snow and I was reminded of something I read or heard somewhere.

You know that steroetypical image of putting a ring of stones around a fire? Well I'm sure there's a warning that you shouldn't use stones that have come from a stream or at least been submerged as they could explode.

Has anyone ever had first hand experience of this phenomenon?

Yes basic safety would dictate you shouldn't, if there's a slight risk but just how likely is it of ever happening? 1 chance in 10 or about as rare as seeing Elvis crash a UFO into the head of the Loch ness monster?

Thanks for reading.

Biker

Have not had that but I have seen concrete explode, folks at a campsite found a big flat slab that seemed perfect as a reflector at the back of the fire, it was really quite scary firing decent sized pebbles about the place like bullets.

 

[Biker]

Have not had that but I have seen concrete explode, folks at a campsite found a big flat slab that seemed perfect as a reflector at the back of the fire, it was really quite scary firing decent sized pebbles about the place like bullets.

Yeah I've seen that happen too, a welder was welding up a angle iron frame directly on a concrete floor, the heat from the torch must have done something inside the concrete and it went pop rather dramatically. Someone said the reinforcing rods had expanded, but that seemed a bit extreme to me, that'd really take some serious heat for that effect, but I could be wrong.

 

[phill_ue]

It only needs to go bang in your face once for it to spoil your day, best to avoid them. It is the small amounts of water soaked into porous stone that heat up and turn to steam that makes the stones explode. Personally, I never use stones, but if I was going to I wouldn't use glassy rocks or stones straight from a stream.

 

[wattsy]

not just rocks from streams i've had it happen with slate once too i steer well clear of rocks if i can

 

[mr dazzler]

LOL when I was a member of the scouting fraternity, (some 35 years+ ago), we did the opposite. For a laugh we would heat stones right up then throw them in the Tees and sometimes they exploded. But we did lots of dangerous stuff then and thought nothing of it.....

 

[jonajuna]

there is this evidence..................................

http://www.youtube.com/watch?v=G7wcP1u4nsY&feature=related

 

[JonathanD]

I've seen it happen many a time when on military sea survival courses. Great cracking explosion, brilliant. Scares the living crap out of you. I've never seen anyone injured though.

 

[Locky]

I remember my mates and I had a disposable bbq, and so we put it on a large thin flat stone to not bur the grass and for some height.
stone popped and cracked and the sausages got airborne 3 inches. scary at the time but oh so funny.

 

[andythecelt]

When I was a kid my Grandad was a proper pyromaniac. He never threw anything out that would burn, he'd stash it on the riverbank on his land until he had enough for a blaze. We all loved it of course and spent a lot of time with him learning about knives and fires and so on. Our mother though used to curse, we'd frequently come home with holes melted in clothes from hot chunks of stone thrown out of the fire. One time I didn't notice it landing on me and it melted through my trousers onto my skin. I jumped up and it slid down my leg. It wouldn't have been much of a problem if it had just dropped out the bottom of my trousers (purple ones, hey it was the 70's!) but it went down the inside side of my trainer. I started yelling and hopping around while my brothers laughed their a**es off. When he realised what was going on my grandad, ever the practical man, saw a simple solution. He threw me in the river.
I had a burn on my thigh, smaller ones dotted down my leg and a burn on my instep.
It's not just slate that can go bang, I'm no geologist but I've seen plenty of different types go off with a hell of a bang.

 

[WolfCrafter]

Nice one Andy, I love a good story!

 

[Wayland]

I had a camera lens chipped by a stone that cracked and blew a chip off that I felt hit the camera.

Glad it wasn't my eye.

 

[Shewie]

I've seen plenty of cracked stones around fires but I've never seen one go.

I did something really dumb a few years ago though whilst burning a load of buddleia cuttings in our mesh incinerator in the back garden. I let a good 6" high pile of embers build up on the concrete yard underneath, normally I shovel them onto the veggie patch as I'm going along but it was full of salad crops this time. After about an hour of burning there was a low popping noise and a sudden jolt in the ground, a big cloud of red hot embers filled the air and tiny pieces of concrete were flying about all over the garden. As it settled down I pushed the incinerator out of the way to check the damage, a perfectly round saucer shaped crater about 12" across and maybe 3" deep at the centre. The pop had also sent out around three or four radial cracks, one of which almost reached the kitchen about 25 yards away.

She wasn't a happy teddy I can tell you.

 

[WolfCrafter]

More story's .. More story's.. This is turning into a 'Cracking' thread!! .. Get it?.. 'Cracking' .. Dow!!

 

[maddave]

Yup I've seen a few explode. I actively encourage people to put logs around a fire instead, because ya can't tell by looking which ones are gonna blow !!

 

[Rory McCanuck]

Yeah I've seen that happen too, a welder was welding up a angle iron frame directly on a concrete floor, the heat from the torch must have done something inside the concrete and it went pop rather dramatically. Someone said the reinforcing rods had expanded, but that seemed a bit extreme to me, that'd really take some serious heat for that effect, but I could be wrong.

Back when I was doing a lot of welding on trailers, I had one recurring repair that involved standing on my head and cutting large parts of the frame apart.
Once,after a large pile of slag built up, the cement underneath it exploded. A chunk of something hit my welding mask, broke it, then chipped my eyeglasses underneath. The only injury I had was from smacking my head into the adjacent suspension, but I learned to put a layer of dirt, scrap steel, whatever on the floor first. Also, keep a change of underwear in my locker.....

 

[Chinkapin]

Over the years I have seen quite a few "pop." My experience has been that any smooth stone that has a surface that you can tell by looking would not absorb water, may heat and cool too rapidly and simply break. There will be some noise, perhaps even fairly loud, but the stone will simply break and not explode.

Any stone that looks like it would absorb water if you poured some on it, probably will and as stated in one of the posts above, it will heat the water, the water will turn to steam and it will probably explode. Violently enough to possibly cause injury.

Stay away from sandstone, slate, and anything porous and you will be completely fine. I examine each rock, build the fire ring and never give it another thought. There is really nothing to worry about if you can tell porous from nonporous. If you don't trust your judgement, you best not use rocks.

 

[Grey Owl]

A few years ago we had a couple of close friends that we often joined for canoeing and hiking adventures. They had a somewhat neurotic Black Lab that had a great fear of water and fire. On one particular canoe trip on the North Saskatchewan River, we had pulled over to the bank and discovered an existing campsite complete with existing firering.

After dinner we had pot of bushtea on the fire and were experimenting with cornmeal ashcakes (a very poor experiment). The poor dog had finally gotten over the trauma of riding in the canoe, and after inching towards the fire, was peacefully sleeping on the ground beside us, enjoy our company. All of us were lying on the ground, relaxing, enjoying the moss beneath us and the sun filtering through the Lodgepole Pine. Just then a phenomenal explosion occurred that sent all of us whimpering and scampering for the trees, the fire included.

When we came back to our site of former quiet reverie. The discrete firering was scattered over a radius of 2-3 metres, with some fistsized chunks twice that distance away. Our fire was nearly out and scattered over the same distance and the dog did not return until the wee hours of the morning.

 

[SimonM]

I saw a hangi being prepped with concrete rubble once...too late to give a warning the rubble was shovelled into the fire.

No one believed me how dangerouse this could be until pebbles of hot concrete started to be ejected...we retreated to a safe distance and had a beer!

Simon