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How to EMPTY a gas cylinder

locoboy - 12/5/05 at 06:35 PM

Chaps,

I am wanting to COMPLETELY empty a propane cylinder so i can cut it in half!

I have depressed the valve on the top and i can no longer hear the 'pffffft' you normally get when there is some pressure in there.

Does anyone know it the brass valve will screw off the cylinder? if so is it right or left hand thread?

I tried to drill a 1mm hole in it going nice and slow with WD40 as a lube but i made pretty much no progress, its really hard steel i think.

Cheers

bigandy - 12/5/05 at 07:08 PM

Not sure about the thread, but when you do get access to the inside of it, the best way to completely evacuate it of all gas is to fill it completely with water.....

NigeEss - 12/5/05 at 07:28 PM

Not sure either if it screwed, but if it's brass then drill that as it shouldn't spark.

longwayoff - 12/5/05 at 07:57 PM

Must be a blunt drill I drilled one and used it as a compesed air tank with no hassle

And yes waters is the best way of getting the gas out but I suppose chucking it on a bomb fire might work as well but then I expect it would also put an end to you trying to drill it and every thing else

Glan Noye - 12/5/05 at 08:28 PM

Please be careful.Read this http://www.thisisbournemouth.co.uk/dorset/poole/news/POOLE_NEWS_NEWS0.html Apparently this happened while an oxygen cylinder was being cut up for scrap.The explosion was heard miles away.Glan.

907 - 12/5/05 at 08:31 PM

quote:
Originally posted by longwayoff
Must be a blunt drill I drilled one and used it as a compesed air tank with no hassle

I'll second that.

I submerged mine in water and drilled it with a battery drill. (240v and water don't mix)
The water level was about 25mm above the place I was drilling and the valve had been left open an hour or more.
But when the drill broke through there was still enough pressure inside to soak me as the gas bubbled out.
The neighbours were highly amused, watching from behind a wall. Chickens!

Paul G

Russ-Turner - 12/5/05 at 09:02 PM

quote:
Originally posted by Glan Noye
Please be careful.Read this http://www.thisisbournemouth.co.uk/dorset/poole/news/POOLE_NEWS_NEWS0.html Apparently this happened while an oxygen cylinder was being cut up for scrap.The explosion was heard miles away.Glan.

Sounds like a right mess.

mangogrooveworkshop - 13/5/05 at 12:05 AM

quote:
Originally posted by Glan Noye
Please be careful.Read this http://www.thisisbournemouth.co.uk/dorset/poole/news/POOLE_NEWS_NEWS0.html Apparently this happened while an oxygen cylinder was being cut up for scrap.The explosion was heard miles away.Glan.

email that to the darwin awards people they love those stories

britishtrident - 13/5/05 at 05:59 AM

it really should be steamed out even them I would want to ventilate it properly while cutting.

NS Dev - 13/5/05 at 07:34 AM

why does it need to be a propane cylinder and what is it for?

I ask cos I have done this many times, but I just go to my local tip and get an old inert gas bottle.

I used "ex-pub" co2 bottles to make a post rammer and a pressure-pot beadblaster, and I have cut up a few balloon gas bottles, which are similar to the smaller (17kg?) butane or propane tanks, but only had helium in them so are perfectly safe to cut up.

As ever,, the Tip is a very useful source!

Wadders - 13/5/05 at 07:44 AM

I once saw a full propane cylinder go off, during an out of control fire in a burger van at the Bulldog bash, bloody impressive! it flew like a missile for about a hundred feet, creating a big pressure wave behind it,hit another burger van and blew that up, causing a huge fire which destroyed another half a dozen stalls.
Amazingly AFAIK no one was hurt, except a few idiots caught looting in the aftermath.
The band played on throughout the whole episode, with 40 foot flames as a backdrop, very cool.

I'm not suggesting this will happen to you BTW! , although i have had bike petrol tanks
pop when welding, even after being filled with water overnight, so go careful.

NS Dev - 13/5/05 at 07:49 AM

CRIPES!!!!!!!!!!!!!!!!!

some show!!!

DarrenW - 13/5/05 at 08:07 AM

I was led to believe that the gas can permeate into the steel over time making it very hard to remove. I recall reading a mag whereby someone recommended filling it with inert gas first, exhaust gas at a push (as long as the vehicle isnt running rich.
NS DEV - i thought helium was flammable??? Might be wrong. What was that airship filled with (hindenburgh??). I hope its not - my 3 year daughter has a ballon full of it at home!!!

There must be a safer way to get a pressure vessel - if thats what you want. How do you test them after the mods to make sure they are safe - rather you than me.

flak monkey - 13/5/05 at 08:22 AM

Helium is a noble gas, to all intents and purposes, it is totally inert.

Hydrogen on the other hand....

Of all the suggestions so far i would say the submerging in water and then drilling is the best bet. Buy yourself a small titanium coated drill, or if you are having real trouble get a cobalt one... and go at it with that. Then you should get through ok.

David

britishtrident - 13/5/05 at 08:52 AM

quote:
Originally posted by Glan Noye
Please be careful.Read this http://www.thisisbournemouth.co.uk/dorset/poole/news/POOLE_NEWS_NEWS0.html Apparently this happened while an oxygen cylinder was being cut up for scrap.The explosion was heard miles away.Glan.

Some years back a welder was brought in to use a thermic lance to cut through the concrete base of an old dockside crane at what had been the WW2 emmergency port at Cairnryan --- afterr cutting through one to his horror he discovered the aggeragate in concrete contained WW1 mills bomb hand granades -- while it is almost certain these had been made safe he opted to look for work elsewhere.

What ever happed to thermic lances ? -- one day tomorows technology the next left behind.
What ever happed to jetpacks ? a book idea for uncle Ron and Mr Haynes -- "Build a Jetpack (and race it) for 250 pounds or less !!!!"

[Edited on 13/5/05 by britishtrident]

britishtrident - 13/5/05 at 08:56 AM

quote:
Originally posted by Wadders
I once saw a full propane cylinder go off, during an out of control fire in a burger van at the Bulldog bash, bloody impressive! it flew like a missile for about a hundred feet, creating a big pressure wave behind it,hit another burger van and blew that up, causing a huge fire which destroyed another half a dozen stalls.
Amazingly AFAIK no one was hurt, except a few idiots caught looting in the aftermath.
The band played on throughout the whole episode, with 40 foot flames as a backdrop, very cool.

I'm not suggesting this will happen to you BTW! , although i have had bike petrol tanks
pop when welding, even after being filled with water overnight, so go careful.

In the process must have save hundreds from dying of salmonella, BSE and heart disease.

[Edited on 13/5/05 by britishtrident]

Peteff - 13/5/05 at 09:35 AM

The pressure rating on these is not as high as compressed gas cylinders, they are only about 90psi. I used a lorry brake tank to make a compressor way back when, they are rated higher.
What ever happed to thermic lances ? I used one once to cut a skull out of a furnace when an electrode broke and it shut down on us. They were evil things with very little control once they were lit. If I remember right it was like a conduit filled with iron filings type material and had oxygen blown through it. I know it needed a burning torch to light it.

NS Dev - 13/5/05 at 02:18 PM

quote:
Originally posted by britishtrident

quote:
Originally posted by Glan Noye
Please be careful.Read this http://www.thisisbournemouth.co.uk/dorset/poole/news/POOLE_NEWS_NEWS0.html Apparently this happened while an oxygen cylinder was being cut up for scrap.The explosion was heard miles away.Glan.

Some years back a welder was brought in to use a thermic lance to cut through the concrete base of an old dockside crane at what had been the WW2 emmergency port at Cairnryan --- afterr cutting through one to his horror he discovered the aggeragate in concrete contained WW1 mills bomb hand granades -- while it is almost certain these had been made safe he opted to look for work elsewhere.

What ever happed to thermic lances ? -- one day tomorows technology the next left behind.
What ever happed to jetpacks ? a book idea for uncle Ron and Mr Haynes -- "Build a Jetpack (and race it) for 250 pounds or less !!!!"

[Edited on 13/5/05 by britishtrident]

Oh, thermic lances are still very much used! I think all the hype that made them all too well known was a couple of big bank jobs that used them wasn't it??

Certainly still used regularly in demolition and heavy plant dismantling. Murex sell all the bits.

Rorty - 15/5/05 at 05:50 AM

I don't know about making gas cylinders safe, but when welding petrol tanks, I often did as DarrenW said; just hold the filler neck of the tank over the end of the exhaust of a running engine for about a minute. This will purge all flamable vapour.
What is the end purpose of the gas cylinder once it's been emptied?

britishtrident - 15/5/05 at 10:49 AM

Problem with degassing petrol tanks is enough petrol can still be lying in the seam weld for air/petrol mixture to get back into the explosive range ---- note explosive not just flamable.

Rorty - 15/5/05 at 01:03 PM

quote:
Originally posted by britishtrident
Problem with degassing petrol tanks is enough petrol can still be lying in the seam weld for air/petrol mixture to get back into the explosive range ---- note explosive not just flamable.

I agree petrol can be present in seams and deep rust, but the whole idea behind filling the tank with carbon dioxide before welding, is to purge any oxygen thus eliminating the posibility of combustion.
I would never repair or otherwise weld a tank that had only been washed out as it's not enough to remove petrol fumes.

locoboy - 16/5/05 at 06:03 PM

quote:
Originally posted by Rorty

What is the end purpose of the gas cylinder once it's been emptied?

Thanks for all the replies,

The end purpose is to cut it in half lengthways and weld on a couple of hinges and turn it into a BBQ!

stephen_gusterson - 16/5/05 at 06:46 PM

10 or 20 quid buys you a barbecue with much less risk of injury!

dont gas cylinders have a deposit on them? take it back and get your money back if so....

atb

steve

stephen_gusterson - 16/5/05 at 06:48 PM

http://www.krl.com.au/whatisalance.htm

indykid - 16/5/05 at 08:03 PM

quote:
Originally posted by stephen_gusterson
10 or 20 quid buys you a barbecue with much less risk of injury!

atb

steve

�500 will buy you a nice enough car, that will give a couple of years service at least, with much less risk of injury

at that rate, why even think of building one.

alright, there is an obvious safety risk, but hell, if you were selling them for cost, i'd definitely buy one over a "normal" barbecue.

barbecueing in a gas bottle, cool

thermic lances, super cool

just my musings, no offence intended
tom

Simon - 16/5/05 at 09:17 PM

I've chopped up two calor bottles to turn into "no-pressure" vessels - we used one for a vacuum chamber.

What I did was remove brass top so largish hole. Filled with water several times, including with washing up liquid, emptied out, filled with clean water and left for a day or two.

Cut with an angle grinder. Wear good clothing, gloves, face mask etc etc.

I also welded a return feed for my Mini tank when I turboed that. Cleaned out tank in above fashion. Then welded tube to side, THEN drilled through tube and into tank.

ATB

Simon

locoboy - 23/5/05 at 08:57 PM

I have other BBQ's too but i just wanted to have a little project to crack on with!

I have tried to screw out the brass valve but to no avail

Gusto, It did have a deposit on it about 5 years ago! but Shell Gas is no longer operating on the bottles side so no one will take them back - believe me i have tried!

Think i will try to drill through the brass valve.

[Edited on 23/5/05 by locoboy]