Gas canisters/bottles/containers can be re-purposed into many wonderful things such as furnaces, BBQ's and rocket stove mass heaters.
"best way to make them safe is to knock off the valve (after making sure empty obviously), then fill it with water..... the filling will water will safely remove all the remaining residue gas inside..... then its innert and safe enough to bring in the angle grinder." - Nin
"Knocking the valve off is still very dangerous as if there's simply no gas coming out you can't be sure if it's empty or the valve has jammed shut. My solution has been to make a barbed hose adaptor for the valve and use a garden hose to force water into the tank. The gas will compress more than the water. You have to do a number of passes, but each time you remove the hose you'll get a burst of gas/air and the assurance you're displacing the contents with liquid. When all that spurts out is water, you know it's totally full. Then it's safe to drill a hole or knock the valve off. Billy recommended to me to put some bleach in at this stage to remove chemical residue from the inside of the tank." - Sci
"If you're using a gas bottle that contained something flammable, then
be bloody careful when you're dismantling it.
Once you've got the internal air pressure equalised with the atmospheric air pressure, you can unscrew the valve. Note, the flammable gas vessels in this country use a valve that can be unscrewed, hence they're replacable/maintainable. It's only the inert gas containers that don't.
Then, with valve removed, pour water in till it's full of water, and all of the gas has been displaced.
Then add bleach, or washing up liquid, soak, agitate, empty, and repeat at least 3-4 times, there's a lot of hydrocarbon residue that gets caked onto the inside of the tanks, When the water is coming out clean then it's safe to cut open. ^^^^^Citation please I can find zero evidence to support this theory!^^^^^
Always pay attention to safety when dismantling any wombled materials. " - billy
"Advice on how to create wood burning stoves is already widespread on the internet. This is not only dangerous, but unlawful. Subsequently, Calor will consider pursuing legal action against these websites and anyone who is found to be unlawfully tampering with cylinders."
As I've discussed this on other forums, good luck to Calor. Might be worth putting the warning about commercial gas cylinders still being the property of the respective companies. It's a con of course, because I paid a 'deposit' for my BBQ bottle. Each time I take it in, it's not filled, it's swapped, so I don't keep the same bottle, therefore it's a little hard to understand why my deposit disappears after 5 years...
Saying that, my two burnt out bottles I found which I couldn't have identified even if I wanted to are in the process of making my wood fired hot tub. - tim_n