On an aligned subject, over the weekend I had great success re-filling a standard green gas can (WE brand I think) from the residual propane left in a couple of the plumbers bottles. The trick is to find the correct sized plastic tube to join the two nozzles (i.e. the original nozzle on the green gas can, and the madbull style/clone adapter for the plumbers bottle) - and ensure it is strong enough. In testing, most ball point pen inner ink 'tubes' are too thin to fit the nozzles and too flexible. The perfect solution was a gel pen - that had a much thicker ink 'tube' and much stronger. It was then easy to leave the plumbers bottles on the radiator to gently warm them, and pop the empty green gas can outside in the cold to cool it (or presumably, the freezer in the summer). Then, stand the green gas can upright, slip the inch or so long length of gel pen tubing over its nozzle, invert the plumbers bottle with its adapter inside you gel pen tube, and push down hard - depressing both nozzles. You can hear (and see) the liquid gas transferring, and feel the green gas can warm up. Do it slowly in stages, and repeat the warming/cooling process enough times as it takes in order to maintain the pressure differentials.
Previously I was left with a load of almost empty plumbers propane cannisters that were as good as useless - now I have an almost full green gas can, to use without faffing around with adapters! By pre-filling the gel pen tube with a light silicone oil before inverting the plumbers cannister and filling, you have the option of adding your preferred amount of silicone to the mix too. In terms of safety, go slow, and best not overfill the green gas can - ideally know how much it 'should' weigh when full with its original load of gas when purchased. Also, the plumbers propane bottles have pressure relief valves, but still, it would seem unwise to heat them up enormously on a radiator etc.
I would imagine that this technique could also make more viable the use of those mini green gas cans that are a useful size to cart around with you during a game, but are an expensive way to buy gas.
