Refilling Gas Canisters

[hikin_jim]

Of course it's possible to refill backpacking type gas canisters. But what are the real risks? What are the practicalities? Is it even worth it?



Please join me as I explore Refilling Gas Canisters

HJ

[tuswm]

what about refilling them using 100% propane from a large out door grill canister.

[4eyedbuzzard]

what about refilling them using 100% propane from a large out door grill canister.

They would likely rupture (and explode if an ignition source was present) as propane boils at -44° F. Butane boils at 31° F for comparison, isobutane at 11° F. The pressure would be too much for the canisters to handle.

[bamboo bob]

but why would you bother?

[TOMP]

With the right connectors you could theoretically refill propane into the propane coleman canisters, but would it be worth it? Maybe you could get your local propane supplier to do it since they have a little more experience with it.

[Slo-go'en]

Is it even legal? Not that that matters much...

On the practical side, with the system pictured above, you'd never be able to completely transfer all the gas from one canister to another because the preasures will always end up equal between the two. If the volumes of the two cansisters are the the same or roughly equal, you'll end up with two half full canisters to start and it goes down hill from there.

[hikin_jim]

what about refilling them using 100% propane from a large out door grill canister.

4eyedbuzzard is correct. Propane has quadruple (at 70F) the vapor pressure of butane. A BP'ing type canister can't handle it.

HJ

[hikin_jim]

but why would you bother?

Why bother to fill with 100% propane? Cold weather performance. But let me stress that you can't. A BP'ing canister can't handle 100% propane. WAY too high pressure.

But if you could, it would work a lot better. Butane stops vaporizing below 31F. Propane continues to vaporize down to -44F. HUGE difference. That's why a lot of people use white gas for cold weather. Canister gas has problems.

HJ

[hikin_jim]

Is it even legal? Not that that matters much...

The Dept. of Transportation regulates interstate commerce. Their regs forbid (as I understand it) transport of refilled canisters of this type. Therefore, it would be illegal to transport across state lines.

On the practical side, with the system pictured above, you'd never be able to completely transfer all the gas from one canister to another because the preasures will always end up equal between the two. If the volumes of the two cansisters are the the same or roughly equal, you'll end up with two half full canisters to start and it goes down hill from there.

Well, actually, that's not quite right. Think about it. The majority of the fuel is what? It's liquid. If it were two tanks of vapor, then what your saying would be absolutely true. You'd get equalization, and then transfer would stop. However, with liquid it's possible to transfer far more. I've been doing it for about two years. Normally, I can transfer all but a few grams.

HJ

[Sly]

I have a friend that made a valve system to fill backpacking canisters with whatever the fuel is that comes in 1lb Coleman canisters. He'd have the backpacking canister on the bottom and Coleman on top but inverted and would guesstimate when the bottom one was full. That worked great until one day his wife's pack exploded while hiking in the heat of the sun. Thankfully, she wasn't injured and is not a cripple.

My suggestion: pay the $4.

[4eyedbuzzard]

I have a friend that made a valve system to fill backpacking canisters with whatever the fuel is that comes in 1lb Coleman canisters. He'd have the backpacking canister on the bottom and Coleman on top but inverted and would guesstimate when the bottom one was full. That worked great until one day his wife's pack exploded while hiking in the heat of the sun. Thankfully, she wasn't injured and is not a cripple.

My suggestion: pay the $4.

Wow. She's lucky. Sounds like he filled it with pure propane. You would think people clever enough to make adapters and such would know better.

[Sly]

Wow. She's lucky. Sounds like he filled it with pure propane. You would think people clever enough to make adapters and such would know better.

He wasn't called The Professor ('95,'00) for nothing. or maybe he was!

[Papa D]

You can punch holes in the old ones and recycle with scrap metal which is probably the "greenest" thing to do with them - if you like re-fillable, I would suggest just using a liquid fuel stove, but it is a cool idea.

[hikin_jim]

Wow. She's lucky. Sounds like he filled it with pure propane. You would think people clever enough to make adapters and such would know better.

Yes, she was lucky. Maybe I should mention:

Do NOT fill backpacking type canisters with 100% propane under any circumstances.

HJ

[Papa D]

yes, she was lucky. Maybe i should mention:

do not fill backpacking type canisters with 100% propane under any circumstances.

hj

you scared meeeee!

[hikin_jim]

you scared meeeee!

Good!

Seriously though, refilling backpacking type canisters with 100% propane IS scary. The lightweight steel can't contain the pressure of propane. At 70F, propane has quadruple the pressure of butane. You need a big, heavy-duty steel container like the 16.4oz/465g Coleman containers. 100% propane + backpacking type canister = KABOOM. Not good.

HJ

[TOMP]

Seriously ppl dont hurt yourself over saving a few cents.

[hikin_jim]

Seriously ppl dont hurt yourself over saving a few cents.

Refilling with 100% butane is reasonably safe if your careful -- as safe as working with white gas for example. Refilling with 100% propane is extremely dangerous if you're putting that propane into a backpacking type canister.

HJ

[Slo-go'en]

Well, actually, that's not quite right. Think about it. The majority of the fuel is what? It's liquid. If it were two tanks of vapor, then what your saying would be absolutely true. You'd get equalization, and then transfer would stop. However, with liquid it's possible to transfer far more. I've been doing it for about two years. Normally, I can transfer all but a few grams.HJ

The reason it's liquid is because it is under considerable pressure. Gas can be liquified in two ways - make it really cold or put it under a lot of pressure. Unless a mechanical pump is used, transfering a gas from one container to another will continue only until the pressures are equal in both. The gas will remain liquid as long as the pressures remain high enough in both containers.

The gas container is "empty" when the pressure of the gas inside the container is the same as the atmospheric pressure. That's why throwing an empty gas canister into camp fire isn't a good idea. There is still some flamable gas inside and once it gets heated up by the fire, the canister can explode, creating a nice little fire ball.

[chief]

Slo-go'en is right, once the pressure equalizes, the filling stops. However, just chill the canister being filled (ice water bath is best) and warm the filling canister (in the sun perhaps). With a little patience, you can get a canister 80% to 90% filled. Okay, a lot of patience!