Empty gas bottles... any use?

Having just read this thread about reusing materials...

http://www.model-engineer.co.uk/forums/postings.asp?th=95670&p=5

... I've got a growing collection of small empty propane bottles (like this http://www.diy.com/departments/gosystem-400g-gas-cylinder-cylinder/255289_BQ.prd)

Can they be safely de-pressurised and cut up and if so, is there anything inside of use and what's the shell made from?

If not useful I suppose there's a place for them at the local tip?

That size, possibly a modified Schreckling gas turbine **LINK**

If the heating gas bottle size, then a Chastain style iron melting furnace: **LINK**

May be useful one day.

Regards,

Richard.

So have I. I did some research on them and they are proofed at over 300 psi. Made of mild steel about 1 mm thick. Depressurise by attaching the torch and leave on outside for a bit! But still gas inside. I bought a kit years ago of a torch with an oxygen bottle too, which lost most of its puff years ago, so I've adapted this as a small pressure reservoir, only for 40 psi. I'd be chary about doing the same with a gas bottle as getting all the propane out would be tricky.

Years ago I designed a gas bottle meter and that project involved cutting a calor gas bottle in half. I didn't do it myself but no one got blown up. If you did it outside on an empty cylinder with a hacksaw and plenty of coolant it would probably be safe enough. But as part of that project we found that gas bottles were, in the words of a university metallurgist we consulted, a "metallurgical dog's breakfast' so I wouldn't have high hopes of using them for anything else.

I gather that they can be recycled via the supplier, in principle, though whether any of the suppliers know that I doubt!

If you are worried about residual gas you can pump in water which gradually pressurises the remains, then let that out and repeat until 100% water then reverse with plain air to expel the water. It will then be damp inside so you must cut it up not use it as a pressure reservoir that will rust internally. Seem to often be used as basis for woodstove but really to thin to risk for that. Maybe ok as chimera outside.

What about co2 fire extinguishers I wouldhave thought there would be a use for them they can be made from steel or aluminium, a 5kg one is around 6" in diameter

Mick

Going slightly off the subject of your bottles. But still on gas bottles .

Our local scrap yard cuts in half the BOC acetylene bottles. Welds on 2 handles & flogs them as post  rammers.

I bought one without handles & have sliced off 3 - 3/4" lengths 5.5"  diam for rims for the front wheels & flywheel of my traction engine. They have 1/4" thick walls & I have enough for another 10 .- cost me a tenner.

Re calor gas bottles I have a small one ready to cut up, once i get the remaining gas out, & will cut it to give the rims for my rear wheels ( 10" diam).

Edited By Sam Longley 1 on 27/01/2017 13:30:38

Contemplated using either one of the propane, well butane in my case, or similar size CO2 bottles as the reservoir for a Bijur style mister system. Usually run in the 20- 30 psi range so no great demands on the cylinder but its more comfortablee using something actually intended as a pressure vessel instead of "ought to be strong enough".

Various designs out there for the business end or drop £15 (ish) on E-Bay for a proper dual feed one. Even after buying a regulator and solenoid valve its fairly viable compared to the £70 - £100 a used Bijur goes for on E-Bay. Assuming said Bijur is all good of course. The prices of official Bijur hoses and delivery lances are not exactly home shop friendly.

Clive.

Hmmm, thanks for all the replies. Doesn't seem as though they'll be an awful lot of use especially if the shell is only a mil thick. Maybe I should dump them (I'd love to chuck them on a fire and watch them go pop... through a pair of binoculars!).

Had a couple of CO2 extinguishers, bottom halves makes excellent melting

pots for aluminium

Hi PaulR, these probably come under the Control of Pollution (special waste) Regulations 1980, so be careful where you dispose them and they may not be accepted at a scrapyard, pressurised containers and all that. Do you know if B&Q will dispose them or not?

Regards Nick.

We used to throw them onto bonfires at Guy Fawkes, to liven things up a wee bit.

Some just fizzled but a few gave a reasonable bang

We only threw a full camping gaz canister on once though because it blasted the bonfire all over the field and ruined the party

Edited By Ady1 on 27/01/2017 16:01:09

A problem with reusing these 400g bottles is that they have essentially a Presta-style valve (like a high pressure bike tyre) in the top, with a stalk on the screw-on fitting that pushes it down. It only has a very small aperture which is fine for the intended purpose but would make it very hard to flush out or actually reuse as an air reservoir. You have to take this out which involves a bit of drilling, and though I was happy to do that on an empty oxy bottle I wouldn't be so cavalier on an empty propane one. Also the hole in the screw-on valve is tiny, so that needs a lot of modification (i.e. butchering...) to be usable. I'll post a photo when I get a chance. If you could get the valve out there's about a 6mm hole into the bottle, so one could fill with water through a thin tube to dsplace the rest of the gas.

Is that the regs where you have to lob them in the hedge & b..ger off quick, when no one is looking because the local council will not take them

Edited By Sam Longley 1 on 27/01/2017 17:36:56

Well they must have a death wish as acetylene bottles contain acetone as the gas is dissolved in this!! I wouldn't cut up an acetylene bottle for all the tea in China.

If you want to clean out a propane bottle you need to fill it to the brim with water which will push the gas out as it is a welling gas and is heavier than air.

Thanks for more safety advice - exactly why I asked here before even thinking about picking up a hacksaw.

With regard to disposal, I think I saw a place for gas bottles at our local rubbish/recycling last time I visited; I certainly won't be chucking them anywhere else. I have no idea if B&Q or others take back the empties but I'd be surprised...

WEEEEEEEEEEEEEEEE regs? they may well have to dispose of them same as batteries if you sell them.