Cutting the top of a gas bottle

I have done the same thing that you are proposing, Only I filled it with water while I was doing it and I drilled about a dozen small holes in it while it was full of water Before cutting. that worked for me,always err on the side of caution, and safety.
Broodie H3

I have made many choofers using 9kg bottles and use the same degaussing method as you then I simply let all the water out sit the bottle in direct sunlight for a day then the next day proceed with the cutting.

If the bottle is opened to atmosphere, there will be no more gas inside....cut away.

I agree with DOZER. The liquid gas vaporises above about minus 42 degrees C unless under pressure in a sealed tank. It is also heavier than air so after opening the valve and waiting until is stops hissing, remove the valve and turn the bottle upside down. Any remaining gas will fall out.

If you are still not convinced then blow some compressed air through it and start cutting.

Don't worry about the smell, it is not gas. If you cut the bottle in half and just leave it, the smell will still be there weeks later.

Hi New Boy,

I have done a couple of theses projects over the years. You are right on target filling it with water.

Proceedure as follows.
1 Remove valve
2 Fill with water
3 wait one hour before draining
4 Drain water and work on cylinder in any way you like.

Use an angle grinder, oxy acetylene or whatever you like.

Understand that there will be a gas smell but this is just the odourous stuff they put in the gas to make its pressence obvious which permeates every thing.

Never had a problem doing it this way.

Cheers, Bruce.

Thanks everyone did as proposed and advised all done

Not wishing to hijack the thread, but is there a trick to removing the valve? I have a gas bottle I'd like to do something with but cannot remove the valve at all.

Thanks.

Jack

Mazdave
Bit of an experiment but I,m going to use heat beads and use it as a camp oven cooker
for place open fires are banned. BCF have a simalar S/S one for $60

The valve was already out when returned from the dive shop but it was just a screw in item