Got a small tank that was filled with helium for party balloons that is now empty. I want to cut the top off it and use it for small fires on the beach.
If I cut it open with an angle grinder/cutting disk is it going to disperse me over a large area?

Do it on the beach and live up to your name. You do realise that it will be full of helium at 1 atmosphere?

If it is really empty you will be cutting the top off an empty metal can. what could possibly go wrong*?

*Check my name before taking my advice

Helium is inert, so there's obviously the danger of explosion.

It's probably safe*.

*Safe, from the point of view of someone miles away on an internet forum.

When people cut open gas cylinders for this sort of thing, I think the preferred method is to fill it to the brim with water. Just don't get electrocuted when you hit water 🙂 Spose if you fill it and then empty it, it has to be normal air in there?

Do you have children? If not you could be this years Darwin award winner.
make sure you get a friend to record (from a distance) and put it on youtube:-)

…. You do realise that it will be full of helium at 1 atmosphere?

So when you cut into you'll be subjecting your 1atm gas to erm… 1atm…..

I'd imagine that'll achieve the grand total of diddly squat 🙂

Now if someone wants to try this experiment with a full Liquid helium dewar, I'd pay to watch that 🙂

shoot it from a long distance 😀

dan1980 – Member
…. You do realise that it will be full of helium at 1 atmosphere?
So when you cut into you'll be subjecting your 1atm gas to erm… 1atm…..

I'd imagine that'll achieve the grand total of diddly squat

Now if someone wants to try this experiment with a full Liquid helium dewar, I'd pay to watch that

My point is that it's not actually empty, is it. It's still full of helium.

It depends on how long the tap was left open for after it ran out of pressure.

Either way, breaking open a cylinder of an inert gas at atmospheric pressure won't really do much.

I say breaking open, because although I've never cut one, I have dropped an empty 5ft He cylinder breaking off the hand rail and tap, and apart from a loud noise as the cylinder hit the ground, not a lot happened.

dan – i am not sure what a ' a full Liquid helium dewar' is but how much you paying? I am sure i could give it a go. i am guessing it will be a pretty chilled affair.

just make sure the valve is open so no build up of pressure, aside from that Helium is not flammable thats why it is now the gas of choice for airships

Leave the tap open for a while first, theoretically the remainant of the helium should slowly leave and air'll go in. Instinct says it'll be fine if you cut it open..but then again aerosols and stuff (which I know this isn't…) warn not to pierce the can even when empty…

First you'd need to get hold of 100L of liquid heium in a storage dewar that will set you back about £450 +vat

I'm not stupid enough to try but, if you break the vacuum on a helium tank, it will boil instantly and you're 100l of helium will increase in volume by about 800 times. It starts off life at 4 kelvin (-269C)

Here's a video of someone I kind of know opening up what is effectively a helium dewar to atmosphere in a kind of controlled manner….

Youtube link.

When full the tank would have held about 20-30L of helium, but I'd imagine it wasn't full when they opened it up.

In all seriousness, helium is inert, so there's no danger posed by the gas so long as the pressure genuinely is equalised between the inside of the tank and the outside world.

I'd be more worried about the construction of the tank – if you cut box section lengthways for example, it springs open quite violently, because it's welded whilst it's under tension.

Now i know why I've been wondering whether to do this for the last 2 years!!

It's not a 'big' tank (22.5ltrs when full) – just the sort of party balloon package thing that you can buy from Costco etc.
The disposal instructions say to rem0ve the [plastic/rubber] filling valve, open the tap to release residual pressure and tkae to the recycling centre.

Doubt there is even enough helium in there to give you a squeaky voice if the valve has been left open for any length of time. Can you not just purchase a barbecue-pit to have your fire in? Sounds like the diameter would be too small to me.

Yeah, I 'could' but a pit but as this is about the right size (don't want it too big) and free! Not a big issue though – we've made do for years without one.

I like the liquid helium one.

The contents of those cylinders are a air/helium mix. Pure helium is often used in pressure testing for its ability to escape from the tightest of corners (so to speak). The throwh away jobbie you have will be empty after around 30 balloons have been filled and should'nt cause any great risks when cutting open.

About 4 years ago at a cylinder testing plant a BOC member of staff was cutting open a hydrogen cylinder wich had been purged with nitrogen and shot blasted, however small pockets of hydrogen remained in the coroded metal in the cylinder and during the cutting process his nads were very badly burned. The cylnders are cut open using an angle grinder around the neck area. Bit of compo and he was right as rain, apart from his nads.

<'students today… mode> I hope Scott Bouchard paid for all that Helium he wasted – Helium recovery is a costly business. </'students today… mode>

yes take a grinder to it as above have said scientifically you will be right. You can heat the cyclinder to purge more of it but as it is inert why care?

It's a dumb idea without seeking proffesional advice first and they will probably tell you it's a dumb idea. You don't know what is within the tank, hospital is full of people who have done stuff like this. Why take the risk to save a few quid?

IT'S A HELIUM TANK! WE KNOW WHAT'S IN IT, AND WE KNOW IT'S INERT!

Mind you, the lads down at BOC might have filled it with Hydrogen instead for a laugh, you never can be too careful…

Burls, have been in cylinder gas business for years and our retail outlets sell lots of these things and customers often bring them back when empty, we normally empty them and run the fork truck over them and chuck em on the scrap pile. You could probably get into them with a pair of tin snips never mind an angle grinder.

If you do it can you make you are as far away from Ashford, Kent as possible as I've only just re-cemented my ridge tiles. Thanks.

'IT'S A HELIUM TANK! WE KNOW WHAT'S IN IT, AND WE KNOW IT'S INERT!'

When I say within in it I mean what valves etc not the gas! Often tanks/bottles of gas have valves etc within the tank. Just because it's an inert gas doesn't mean it's not dangerous to open the tank. It's a stupid idea.

White101 – Take your point but can't you see mine that if you cut open a tank after taking advice from someone off the internet you need your head read? There may well be other factors which the op doesn't deem relevant to mention but are, oil drums are harmless but many people have been hurt/killed by cutting them open for bbq's.

Here's a video of someone I kind of know opening up what is effectively a helium dewar to atmosphere in a kind of controlled manner….

…and all of a sudden nothing remotely interesting happened.

oil drums are harmless but many people have been hurt/killed by cutting them open for bbq's.

And anyone who wants to start small fires on a beach wants to have their heads examined.

Many people have been hurt or killed as a result of starting small fires or being left stranded on a beach after the tide's come in.

Kept away from empty helium canisters, small fires, and the beach, ffs.

oil drums are harmless but many people have been hurt/killed by cutting them open for bbq's.

And anyone who wants to start small fires on a beach wants to have their heads examined.

Many people have been hurt or killed as a result of starting small fires or being left stranded on a beach after the tide's come in.

Kept away from empty helium canisters, small fires, and the beach, ffs.

Whats starting a fire on the beach got to do with it? In no way is it along the same lines. Cut it open, don't cut it open, I don't really care I don't have to do it, it's up to the op but I still think it's a dumb idea.

Be more interesting if it was a half filled propane bottle.

I see your point Burls.
Its a small piece of metal and trying to create a bbq on the cheap when you can get them at halfords, b&q for a tenner or less, risk assessed you might give it a miss.

Kuco, propane, now that would be a different kettle of fish altogether. Keep a fair distance from that one if someone fires up an angle grinder. Good for youtube and nowt else!

I cut a propane cylinder open with a 9" angle grinder once. I was bloody stupid to do so, in terms of potential massive danger, but it was fine.

Shoot a hole it it before you cut it open, just to make sure 🙂

Whats starting a fire on the beach got to do with it?

Obvious I would have thought……….it's risky and unnecessary.

And don't get me started on the idiots who will quite happily take a chance and pop balloons filled with helium 😐

As said above party ballon helium has a hight air content so people stupid enough to inhale it no longer die.

In all seriousness, helium is inert, so there's no danger posed by the gas so long as the pressure genuinely is equalised between the inside of the tank and the outside world.

Whilst I agree that in this case the risk is probably low, the assumption that an inert gas poses no risk is false. Most inert gases are asphyxiants as they can displace oxygen from the immediate atmosphere. If you do decide to do this, make sure you do it in a well ventilated area.

but then again aerosols and stuff (which I know this isn't…) warn not to pierce the can even when empty…

That's because they use butane as an accelerant these days and it is still likely to be under pressure even after the useful contents have been used up.