Well this is going to be a slow build I guess But I should post what I am doing so that someone can point out that I am doing it wrong
So I started with a red calor gas bottle and vented what was left of the gas. More of a fart than a hiss but the bottle was now at atmospheric pressure
I then had to remove the tap on the top. So to do this I used a short piece of 4 x 2 box section steel over the valve this allowed me to get a pair of stillsons on to undo the brass connector.
Next I filled the bottle up with tap water until it was overflowing and left it a few days until the stinky stuff had mostly washed away. This ensures that the heavier than air gas has been purged from the bottle
So I added some tape around my cut lines and prepared to cut the bottle
Simples with my 9 inch grinder. Didnt even use a whole disc for all the cuts
This was when I took the first picture Next to it is the steel crucible I plan to use. The mate that made this up for me said he would do so as long as I wasn`t making a pipe bomb

Made a few hinges from some of the bottle metal and welded them on and reused part of the handle from the top to make a lid lifting handle

I welded a bit of scrap metal grid into the top in preparation for putting the fire cement/ perlite in.