Phantasm Community user sgdragoon recently shared with us his homemade flamethrower replica from Phantasm II and III. As far as fan items go, this is a ghastly good recreation of the actual movie weapon. Sgdragoon's comments on his prop follow and photos of it appear beyond that. Click any photo to see it larger.
I need to fix her back up again, but this allows you to see how she is put together. It is all built off of a length of 2*2 pine. The big cheat is that, instead of using gas cans, I just built the shape out of PVC connectors and end caps glued together (keeps me from worrying about emptying the real thing all the way). Fill the gaps with your favorite filler, and then spraypaint them the appropriate color. Oh, but before you put the final end caps on, bolt on those brass T's and L's, or else you'll be kicking yourself for no longer being able to get into the canisters. You can see where mine have split apart after several years - I need to reglue and repaint those.
I would get those pressure gauges from Harbor Freight or anywhere they are liable to be cheap; they don't need to be high quality (or even work - you could take them off of busted foot pumps). The front grip is from one of those pistol grip hoses at a dollar store. The rear trigger is from a cheap compressed air inflation kit. One of these days, I will replace the cheap plastic hose I used with something designed for gas lines. The pilot light is just some brass hose I had. The real burner is from a gas kit, I think it was for sweating copper pipes? The rest of it is pretty much hose clamps and barbs, plus those brass hangers on the front (I don't actually remember what they are from). Mine obviously needs a little sprucig up (I hate those zip ties). Anyway, hope it inspires you to build your own.
Photos of Sgdragoon's flamethrower prop replica:
Phot of the actual flamethrower prop from propman Wayne Beauchamp: