Who here knows about propane, and the "dangers" involved in doing something like this? The problem with all of these one piece, "refill adaptors" you can buy at places like Harbor Freight, Camping World, etc., is they don't allow you to completely fill the bottle. You wind up compressing the gas left in the bottle you're trying to fill.
This method appears to allow for venting, thereby completely refilling the disposable bottle to full capacity. I also like the fact it has a valve. Are there any unforeseen dangers in this? Other than the obvious, "Don't smoke and do it in a well ventilated area", etc. You can't introduce any more pressure than what is contained in the 20 Lb. tank. So I can't see any danger of, "blowing anything up". The venting process seems pretty simple as well.
The parts and assembly of this tool look to be pretty straightforward. The only thing I'm seeing, (or else not seeing), is the 2 adapters he's using don't look so common. The male POL fitting that reduces to 1/4" MIP internal pipe, along with the female bottle to 1/4" MIP internal pipe, I've never seen. I wouldn't know where to go to even look for something like that. Has anyone here built one of these type of valves? If so, what method did you use?
http://www.instructables.com/id/How-to-completely-refill-a-1lb-disposable-propan/?ALLSTEPS You have to keep clicking on "NEXT" to see all the steps. 