Getting the valve out of a gas cylinder

[nickg]

Im trying to cut up some old propane & butane gas cylinders and i need to get the valve off to flush it out - they dont want to budge - anybody done this before can give me some advice?
Do they just unscrew conventionally or is there a trick, reverse thread super glue or some such?

Cheers
Nick

 

[HillBill]

I think they are reverse threaded. I've done one but it was a couple of years ago, i remember it being a pita for me too

 

[telbert]

Im trying to cut up some old propane & butane gas cylinders and i need to get the valve off to flush it out - they dont want to budge - anybody done this before can give me some advice?
Do they just unscrew conventionally or is there a trick, reverse thread super glue or some such?

Cheers



.
Nick

Ive done this a couple of times to make little garden stoves.I soaked the thread with WD40 a few times and then they came of fairly easy

 

[DanBow]

have you got the valve open while you try?

 

[FGYT]

you need a big spanner that fits properly and a sharp tap with a 4 lb lump hammer to shock it loose

ATB

Duncan

 

[nuggets]

BUT MAKE SURE THE VALVE IS FULLY OPEN AND THE BOTTLE HAS BEEN INVERTED FOR A COUPLE OF DAYS


just to vent out the last of the gas !!!

 

[Ogri the trog]

And its a left hand thread.......

That is it unscrews anti-clockwise!

Ogri the trog

 

[marcusleftthesite]

Once you've got it off the best thing to do is fill it with water to drive all the gas out.

 

[Lee Wright]

If you're making a stove then drill two holes (20mm holesaw is good, slow speed and use lube to keep cool) in the area the flue pipe will be then fill with water and leave for a couple of days to get rid of the gas. Then its just a case of emptying and fire up the whizzer to cut them up

 

[Grebby]

And its a left hand thread.......

That is it unscrews anti-clockwise!

Ogri the trog

Surely anti-clockwise on a left hand thread tightens it??

Standard thread clockwise tightens, anti-clockwise loosens.

Opposite for left hand thread.

 

[Ogri the trog]

Surely anti-clockwise on a left hand thread tightens it??

Standard thread clockwise tightens, anti-clockwise loosens.

Opposite for left hand thread.

Y' know that's probably right - getting myself all mixed up and turned around!

Ain't normal anyway.

Ogri the trog

 

[FGYT]

Y' know that's probably right - getting myself all mixed up and turned around!

Ain't normal anyway.

Ogri the trog

sok your fine if the bottle is upside down

 

[mrcharly]

If you're making a stove then drill two holes (20mm holesaw is good, slow speed and use lube to keep cool) in the area the flue pipe will be then fill with water and leave for a couple of days to get rid of the gas. Then its just a case of emptying and fire up the whizzer to cut them up

!

No

Open valve. Leave overnight

Unscrew valve and fill with water.

Do NOT drill into cylinder before filling with water.

 

[spandit]

I've read that you should fill with water more than once before cutting into it.

 

[Stanleythecat]

Surely the water is just to displace and absorb any residual gas?

 

[Zingmo]

Filling with water will displace all the gas bar a few molecules. It will smell of gas afterwards but there won't be enough to go pop.

On all the cylinders I have done the thread of the valve into the steel cylinder is a conventional one - that is you unscrew it by turning it anti-clockwise. (The threads for connecting things to the valve for Butane cylinders are left-handed to stop you screwing on a propane regulator)

The valve threads are coated with a thread sealant which dries hard. You have to crack this to get the valve turning, so you may need to tap the end of your spanner. (I use a 12" adjustable spanner on the square part of the valves body) I don't reccomend hitting the valve itself as you may snap it off and cause a spark at the same time.:yikes:
The trickiest bit I find is holding the cylinder tight so that it doesn't turn as you try to loosen the valve. Last time I used a steel road pin through the holes in the collar to lever it in the opposite direction.

I am not saying any of the above is safe, so carry on at your own risk!

Z

 

[Lee Wright]

!

No

Open valve. Leave overnight

Unscrew valve and fill with water.

Do NOT drill into cylinder before filling with water.

Care to elaborate?

BTW it will still smell of gas due to the rank slime that's in the bottom to add scent to the gas (in the same way that natural gas is scented to enable you to smell if there is a leak).

Oh, and opening the valve and leaving overnight will do nothing (unless tipped upside down) due to the fact that both propane and butane are heavier than air, why leave overnight with the valve open anyway? Contrary to what the internet academics lead you to believe water will not ignite the remnants of gas in a bottle...

 

[wingstoo]

Strangely enough they aren't in most cases a left hand thread as mentioned above several times, they are a right hand thread which is a tapered thread rather than a parallel one, it is made in with a threadlock compound.

The left hand thread part is the appliance attachment thread, so that the wrong appliances can't be attached. or the wrong regulators.
I have done three such projects and each has been right hand thread, so a proper sized spanner and a good hammer and smack it in an anticlockwise direction. If all else fails and you have followed all the safety advise already given about making sure it is empty then warm the valve body with a blow lamp.

I'll go get a bottle out and give it a try.

(The threads for connecting things to the valve for Butane cylinders are left-handed to stop you screwing on a propane regulator)

I think you will find that both Propane and Butane valves are left hand thread.

 

[nickg]

Ok guys - thanks for all the replys

when i took a close look it seemed to me that the threads on the bottle were conventional so thats a confirmation that i needed as is the info that the threads are seald in - so i shall use a bit more BFAI.
Zingmo that is an ace idea with the road iron and i shall give it a crack (Literally)

Thanks all

Nick

 

[mrcharly]

Care to elaborate?

BTW it will still smell of gas due to the rank slime that's in the bottom to add scent to the gas (in the same way that natural gas is scented to enable you to smell if there is a leak).

Oh, and opening the valve and leaving overnight will do nothing (unless tipped upside down) due to the fact that both propane and butane are heavier than air, why leave overnight with the valve open anyway? Contrary to what the internet academics lead you to believe water will not ignite the remnants of gas in a bottle...

Lee, maybe you made a mistake, but your original post suggested that they should drill into the cylinder before filling with water.

That's a really dangerous thing to do. If you need 'why' explaining to you, then I despair.