Cutting Gas Cylinders Open Safely - HELP

[James1979]

I was in a pub once talking with an old Irish guy who did demolitions. He reckoned they used to get the oxy bottles once they were empty, lay them on a bit of channel propped on a beer crate and whack the valve off with a sledge! Went like a missile he said. They used to do it onto the river, he reckoned there was hundreds of em' in there!!

 

[Memmeddu]

I was in a pub once talking with an old Irish guy who did demolitions. He reckoned they used to get the oxy bottles once they were empty, lay them on a bit of channel propped on a beer crate and whack the valve off with a sledge! Went like a missile he said. They used to do it onto the river, he reckoned there was hundreds of em' in there!!

Let's call green peace
That's pollution and more importantly a waste

 

[James1979]

Bit like skimming stones but for big kids! Not sure when exactly this was, but we were sat in a pub which had been there for ten years I knew of, and that was the site of the scrapyard / demo company he was working from. Probably 80's at best I'd think. A lot has changed since then!

 

[Maker]

I was in a pub once talking with an old Irish guy who did demolitions. He reckoned they used to get the oxy bottles once they were empty, lay them on a bit of channel propped on a beer crate and whack the valve off with a sledge! Went like a missile he said. They used to do it onto the river, he reckoned there was hundreds of em' in there!!

There's a Mythbusters episode where they snapped the valves off CO2 cylinders, I wouldn't want to be within sledging distance, they certainly get going!

 

[James1979]

I'll look that up.....

My limited understanding is that bottle goes forward and valve goes backwards-ish so if youre to the side all is good. However, I aint trying it to find out!

 

[brightspark]

I was in a pub once talking with an old Irish guy who did demolitions. He reckoned they used to get the oxy bottles once they were empty, lay them on a bit of channel propped on a beer crate and whack the valve off with a sledge! Went like a missile he said. They used to do it onto the river, he reckoned there was hundreds of em' in there!!

hmmmm empty and they flew like missiles I bet they were supersonic if they were full then

 

[James1979]

Im assuming its not enough pressure to run burning gear but a bit more than the outside.... If youre stupid enough to do it I'm not certain you'll be worrying about using every last bit of gas in there vs having a laugh! Just seen that mythbusters video on youtube @Maker was talking about. Yup, not trying that.....

 

[Pete.]

I've had a few heart-stopping moments over the years when oxy-bottles have gone over. Burner gets to the end of his hoses and thinks the hose is snagged so gives it a tug - over goes the trolley. Had a couple of gauges bent at the stem but never had a neck snap off thank god.

Nowadays I make sure the guys ratchet-strap the trolley to a column or something.

 

[James1979]

Its the acetelyne I worry about more. Saw some clown clout the bottle trolley with a forklift really hard at once place I was working. It started to feel hot so they called fire service. When they arrived, the procedure was to empty the big Biffa bin, fill it with water and put the cylinder in there and leave it be for 24 hours. Nowt to do with me so I didnt get involved but I was suprised that was the remedy. Told someone else that story and he said when he saw it happed there was no biffa bin so fire brigade made a triangle with three ladders tied together, put a tarp in and filled that.

 

[brightspark]

im lucky if mine went up just chuck it in the work pit its filled with water

 

[Hopefuldave]

hmmmm empty and they flew like missiles I bet they were supersonic if they were full then

When I Was A Lad... the W size hydrogen in the chemistry lab fell and cracked the valve off, crossed the lab, through the brick and block wall, across the car park, through the brick wall around the car park, across the next car park and through the head's brand new Cortina and came to rest in the bushes.

School nurse was a bit overworked that day, providing clean underpants to a class of 30...

Dave H. (the other one)

 

[Pete.]

Just doing a quick bit of maths if I have it right if you knock the neck off a W size bottle let's say you have a 3/4" hole with 220bar coming out of that's 220*14.7*.442= 1429pounds or 649kg of thrust shoving 88KG of bottle. I'd say she's gonna fly!

 

[Seadog]

That'll shove off at around 7.4 m/sec/sec if my maths is right.

 

[Welderpaul]

Just doing a quick bit of maths if I have it right if you knock the neck off a W size bottle let's say you have a 3/4" hole with 220bar coming out of that's 220*14.7*.442= 1429pounds or 649kg of thrust shoving 88KG of bottle. I'd say she's gonna fly!

I've belted the valves off (empty) cylinders with a sledge hammer to scrap them. The neck on the bottle is around 3/4" but the tail end of the brass valve reduces this port down to around 5mm

 

[Screwdriver]

Just doing a quick bit of maths if I have it right if you knock the neck off a W size bottle let's say you have a 3/4" hole with 220bar coming out of that's 220*14.7*.442= 1429pounds or 649kg of thrust shoving 88KG of bottle. I'd say she's gonna fly!

Well even if that's in the right ballpark, it means they're going to fly.

Be fun to stand one on end and fire it up. 'Course, no idea where it's gonna land...

 

[Hopefuldave]

That'll shove off at around 7.4 m/sec/sec if my maths is right.

er, 7.4 G - 7.4 x 9.81 m/s^2, call it 70 m/s^2? But that's only the instantaneous acceleration, as the gas escapes the thrust drops pretty damn fast, I suppose? I know it covered the couple of hundred yards to the head teacher's car before we could work out what happened (and recovered from the hellish racket - my ears rang for hours)

Dave H. (the other one)

 

[Memmeddu]

er, 7.4 G - 7.4 x 9.81 m/s^2, call it 70 m/s^2? But that's only the instantaneous acceleration, as the gas escapes the thrust drops pretty damn fast, I suppose? I know it covered the couple of hundred yards to the head teacher's car before we could work out what happened (and recovered from the hellish racket - my ears rang for hours)

Dave H. (the other one)

That's more likely what 600+ kg/f trust load could be like

i think to have read somewhere that a jet has around that power

 

[eddie49]

That's more likely what 600+ kg/f trust load could be like
i think to have read somewhere that a jet has around that power

Well, maybe a very small jet. Each Concorde engine on afterburner was 17,000 kgf ( 170 kN ).
Each Space Shuttle solid rocket booster: 1.2 Million kgf
At the smaller end of the scale, the rocket motor in a missile such as a Sidewinder is 1,800 kgf, which is getting close to the 650 kgf of the flying gas bottle.

 

[Memmeddu]

Well, maybe a very small jet. Each Concorde engine on afterburner was 17,000 kgf ( 170 kN ).
Each Space Shuttle solid rocket booster: 1.2 Million kgf
At the smaller end of the scale, the rocket motor in a missile such as a Sidewinder is 1,800 kgf, which is getting close to the 650 kgf of the flying gas bottle.

Do you know the WW2 German jet?
It had two engines which had 650kgf each
Obviously modern jets and missiles have much bigger power

 

[jimbo84]

Only ever done it the once and after multiple water purges I filled it with C02 as an extra step, how I knew it was full of C02 I've no idea but pumped some in for a while thinking that the less air in there the better. Was still nervous despite being convinced there was no gas remaining.