I am still working on the refrigeration job at the local store. The next step is to install new filter dryers in the suction and evaporator lines. The dryers are silver soldered or brazed into the line. To melt the high temp silver solder you need a good torch.
I have a nice "Turbo Torch". Normally this torch would be run off of a 20 lb propane tank (like you have on a barbecue). In rural Alaska propane is very expensive due to cost of shipping heavy tanks of flammable gas. A 100 lb cylinder is about $275 and 20 lb tanks are just not available. I do have a bunch of smaller 16 oz propane bottles, but they have a different type of fitting.
Today I rummaged around in my box of misc plumbing fittings and rigged up a way to connect the Turbo Torch regulator to a small bottle. I cut the end off of a cheapo torch, stuck a piece of snowmobile fuel line on the end, ran that line to a hose barb fitting that I screwed into the regulator. (The red arrow points to the regulator.) It works fine and it sure beats hauling around a 100 lb tank.