Hey, gas canisters are expensive. Why NOT just refill them with cheap gas from a bulk propane tank?


A "bulk" propane tank


Yeah, and on eBay you can get a cheap canister refiller that will do just that.

A very dangerous canister refill adapter


But refilling backpacking canisters with this particular canister refiller is inherently dangerous. Find out the whys and wherefores in my latest post:
Canister Refiller -- WARNING

HJ

When you say propane is a high pressure gas, do you mean the big bottles are at a higher pressure than the bottles for camp stoves?

The heavy green steel Coleman-brand bottles are propane, if that's what you mean. I can't read Jim's link right now, but I expect he's speaking of propane having a vapor pressure of 8.4 atmospheres while n-butane's is 2.05. Big difference.

In some countries the bottled gas bought in bulk is butane or a butane blend, while in the States it's always propane. That's why refilling isn't a deadly hobby everywhere, but could be here.



Cheers,

The big green 16.4oz/465g Coleman type 100% propane canisters for car camping stoves definitely have a higher vapor pressure than a backpacking canister.

HJ

Good point, Rick. Perhaps the seller, who is in China, doesn't realize that the fitting he's selling goes to 100% propane in the US and is very dangerous (here). In China perhaps it's butane or a blend and fairly safe.

HJ

I doubt the seller cares.

I agree with the comment on your blog about the tube appearing to not even be adequate to handle pressure. It looks like Tygon... maybe 1/4". If that is the case McMaster-Carr says it is only rated to a couple atmospheres and certainly not capable of handling the vapor pressure of propane:

http://www.mcmaster.com/#standard-plastic-and-rubber-tubing/=gumhs6

That adapter looks like a bad deal all the way around to me.

The seller hasn't responded to my inquiry (although to be fair the time zone difference might account for that). I have filed a report with eBay.

HJ

My guess is the hose barb fittings will blow off before the tygon fails. Of course, that would be the same as the tygon failing, because it would have to fail for the fittings to come off.

what about adapting a tank like this for %100 propane. http://www.rockstartactical.com/Empire_Basics_Carbon_Fiber_88ci_4500psi_Nitro_Tank_p/emp-88-4500.htm

I've mused about something like this for a long while. I'd love to be able to leave home with my always-filled true propane fuel tank. No more partial canisters, no messing with butane. Expensive but it would pay for itself in a couple of seasons.

What I don't know is how much of a fill I'd get transfering fuel from a typical home BBQ propane tank. As it is, I imagine the liability concerns would scare off most companies who'd potentially make something like this.

But I'm not giving up. :-)

Cheers,

If I'm reading things right, that tank is rated to 4500psi. That ought to do it! If you can rig up the filling AND figure out a way to feed the gas to a stove, I think you'd have a workable solution.

How heavy is that type of tank though?

HJ

I looked at several, and from what i can gather just above or below 2 pounds.

http://www.sakworldpaintball.com/guaircafiair.html

this site has some weights, although, the weights are not very consistent. Amazon also has shipping weights, and they show around 2 pounds also. All steal ones rated at 3000 psi are a lot cheaper (40-70 bucks)

I was just down at REI and they were selling a cannister refiller that was a cap to screw onto a cartridge and a needle to slide it into some kind of fuel bottle. I didn't buy one.
Jim

The effective vapor pressure of the propane is lowered by the presence of 80% butane, thus propane/butane fuel cane be put into thinner lighter metal cans. Its been a while but I think you multiply the percentage of each component by its vapor pressure and add them. From this it is obvious that propane/butane will have a bit higher vapor pressure and at a much lower temperature, thus this is a good trade off - the 80/20 mixture.

Ouch. A bit heavy for backpacking. A 100g backpacking canister weighs about 3oz empty. A 200g backpacking canister weighs about 5oz empty if I recall correctly. 32oz for just the empty tank is a bit much.

HJ