refilling a 1lb LPG bottle

Criticalt · Mar 30, 2017

No, but tell me if it works.
I have a propane lantern but never us it because the "disposable" cans are too expensive for me to justify.

Criticalt · Mar 30, 2017

I just looked and they now have refillable 1lb bottles.
Is that what you are talking about? Or are you talking about the disposable ones?

Criticalt · Mar 30, 2017

Jmac00 said:
refilling the disposable ones? I didn't know they made a refillable one?

Me either, they are a couple dollars more but well worth it.
Sam's Club - 1-lb. Refillable Propane Cylinder, 16.4 oz. (ships empty)

speedkills27 · Mar 30, 2017

my old man refills the disposables, he was giddy as a school girl showing me. The setup he uses escapes me at the moment but i can find out if your interested

enigma · Mar 30, 2017

I've done this before. I never messed with the overflow valve on the 1lb bottles, as the pressure from the upside down 20lb tank was enough to fill the bottles about 3/4 of the way by itself. A big CAUTION - do this outside. I had many propane bottles leak after filling them, and there is no way to stop it. The first time this happened to me I was caught by surprise when liquid and vapor started shooting out of the 1 pounder, and by the time I thought to screw it back on the adapter, I was already enveloped in a cloud of vapor. Maybe my bottles were old, but they had been stored in a dry shack. When they leaked it was usually minor. That first one was rare. They do stop leaking after a few minutes, and seem to work normally after that. FYI, it's against DOT rules to transport a refilled propane bottle (the common, non-refillable kind). Had to be a law somewhere... right?

spat · Mar 30, 2017

Harbor freight sells the adapter for $10 give or take. Just screw the two tanks together invert the 20lber open the valve and let it go.

It works fine, don't expect to get them "full", but 1/2 to 3/4 is easy.

C3D · Mar 30, 2017

Remember to smoke a cigar while engaging in this activity.

Criticalt · Mar 30, 2017

C3D said:
Remember to smoke a cigar while engaging in this activity.

And check for leaks with a lit match.

Different Drummer · Mar 30, 2017

I have seen this done many times over the years by about a dozen individuals while camping on BLM land in AZ.
There is even a special valve/fitting sold in RV supply places to do it. Of course it is not marketed as a device for refilling one pound bottles but that is what the vast majority of them are sold for. There is also something in the procedure that gets you a more complete fill if the empties are refrigerated first as I recall. Google around some RV boon docking sites and I am sure there is a lot of information on the practice.

kev74 · Mar 30, 2017

C3D said:
Remember to smoke a cigar while engaging in this activity.

Will a pipe work? I feel more grown up smoking a pipe.

Prominus · Mar 30, 2017

I do it. You have to turn the 20lb tank upside down to get the liquid to go into the smaller tanks. The adapter was cheap. Id say I get them almost 3/4 full.

soylentBlue · Mar 31, 2017

I leave the empty 1lb cylinders in a cooler with freezer packs overnight and leave the 20lb cylinder in the sun to get maximum fill.

Aardvarkjff · Mar 31, 2017

I do it in the winter. Leave 20 pound inside, 1 pounders outside/garage. When ready, bring the big one outside, screw on the adapter and the little bottle to it. Turn this upside down, open the valve so the liquid flows into the little one. After a minute or so, close valve, turn upright, and unscrew little one. I get 75-80% full. Check for leaks.

1075tech · Mar 31, 2017

Nah, pipe and cigar not hot enough to ignite propane. Theoretically anyway. It's not about hot/cold, it's pressure. Propane will always go toward the lower pressure and it only takes a small pressure differential. And yes, it's illegal to transport the disposable cylinders if they have been refilled. The 1# refillables are pretty neat though. Can be used on weed trimmers, and similar small engines that can run on propane.

I converted my 5K generator to run on propane. It will run on a 20# but I have two 100# cylinders just for that, separate from my house tank.

1075tech · Apr 1, 2017

Jmac00 said:
uuum it has nothing to do with pressure, LPG is heavier than air, it's actually more than 50% heavier than air (at sea level) and the vapor is extremely volatile. air at sea level has a density of 1, Propane has a density of 1.55 (again at sea level)

Well, actually, it has more to do with pressure differential than density. You are correct, the vapor is 1.5 times heavier than air. The liquid, which is what we are trying to transfer, has a specific gravity of 0.52, meaning it is nearly 1/2 the weight of water. Neither has much to do with the actual transfer of product.

The reason that cooling the receiving container makes it work better is that it reduces the pressure in that container. The pressure of the container is temperature dependent. The colder the container, the lower the pressure regardless of the volume of propane in it. This is why your BBQ works better in the warmer weather and maybe not so well in the winter.

Under pressure in the container, propane will remain in a liquid state. As you begin to transfer liquid to the "empty" container, the liquid begins to boil, which creates the vapor and builds pressure in the receiving cylinder. It wants to stay a liquid. Eventually, the pressures will equalize and the (liquid) propane will no longer flow. This is why you are generally only able to fill your 1# about 1/2 or 3/4. If you can keep the pressure from increasing in the receiving container or increase the pressure of the transferring container (which is why it was left at room temperature) you can transfer more product.

Propane, whether liquid or vapor, will always flow toward lower pressure.

In any case, be very careful if you are attempting to do this. Propane vapor has a low LEL of about 2.19%. Propane liquid boils at -44*F. That will cause a nasty freeze burn if it contacts your skin.

spat · Apr 1, 2017

1075tech said:
Well, actually, it has more to do with pressure differential than density. You are correct, the vapor is 1.5 times heavier than air. The liquid, which is what we are trying to transfer, has a specific gravity of 0.52, meaning it is nearly 1/2 the weight of water. Neither has much to do with the actual transfer of product.

The reason that cooling the receiving container makes it work better is that it reduces the pressure in that container. The pressure of the container is temperature dependent. The colder the container, the lower the pressure regardless of the volume of propane in it. This is why your BBQ works better in the warmer weather and maybe not so well in the winter.

Under pressure in the container, propane will remain in a liquid state. As you begin to transfer liquid to the "empty" container, the liquid begins to boil, which creates the vapor and builds pressure in the receiving cylinder. It wants to stay a liquid. Eventually, the pressures will equalize and the (liquid) propane will no longer flow. This is why you are generally only able to fill your 1# about 1/2 or 3/4. If you can keep the pressure from increasing in the receiving container or increase the pressure of the transferring container (which is why it was left at room temperature) you can transfer more product.

Propane, whether liquid or vapor, will always flow toward lower pressure.

In any case, be very careful if you are attempting to do this. Propane vapor has a low LEL of about 2.19%. Propane liquid boils at -44*F. That will cause a nasty freeze burn if it contacts your skin.

Technically, if you connected the two (upright) containers with a hose and put one in the sun and the other in the shade, the one in the shade would fill up with liquid no matter what the elevation difference.

The pressure will equalize quickly between them, and the pressure in a sealed containervous like that is exactly determined by the boiling point of the liquid at that temperature. Since the temperatures are different liquid will condense in the cooler container, and boil in the warmer one until there is no vapor in the cold one, or no liquid in the hot one.

1075tech · Apr 1, 2017

Next week, "Why your lighter won't light in the winter".

1075tech · Apr 1, 2017

spat said:
Technically, if you connected the two (upright) containers with a hose and put one in the sun and the other in the shade, the one in the shade would fill up with liquid no matter what the elevation difference.

The pressure will equalize quickly between them, and the pressure in a sealed containervous like that is exactly determined by the boiling point of the liquid at that temperature. Since the temperatures are different liquid will condense in the cooler container, and boil in the warmer one until there is no vapor in the cold one, or no liquid in the hot one.

Correct. Elevation has nothing to do with it. That is why we can withdraw the liquid from an underground tank.

refilling a 1lb LPG bottle

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