Discusson to achieve safest way of refill and use fuel canisters with butane

[Eugene Hollingsworth]

I would like to open the discussion again about refilling isobutane canisters because forum posts and other results from Googleing the topic did not focus on specifics of making this as safe a prospect as we can.

There are many excellent articles about stoves, canisters, (exploding!) and ways of thinking out-of-the box safely so refilling might be viable if the process of filling and using is focused on safety.

There are 3 considerations I’m trying to work through: safety during use, hassle, cost savings, if any.

The goal is to carry a single small canister at 3/4 rated capacity so I don’t have to carry 2 canisters, trying to use up the partial one. (I get it – maybe replace my tent or sleeping bag instead)

For safe use of refilled canisters, I would go with butane rich, no propane, use a canister originally designed for cold weather propane rich fuel, and fill only 3/4 of it’s rated capacity. The butane would be lower gas pressure, the canister designed for higher pressures.

Canisters are not sold or designed to be refilled, indicating the Lindal valve has a limited life span. Assume the maximum number of cycles of the valve would be the person using a large 450 gram canister to bring water to a boil. My use is 30 minutes to an hour maybe simmering chunks of beef in a stew. If I replace the small canister every time I empty a large host canister, I should be well within that number of cycles of the Lindal valve. (Roger has stove efficiency charts to get us in the ballpark, but I have not run the numbers yet.)

The canisters again would be butane rich, 3/4 capacity, and not overly used before replacing. Is this really any more dangerous than jumping out of an airplane, driving on the freeway, or commuting via bicycle?

[Jerry Adams]

or is it more dangerous than refilling white gas canisters?

I think Ryan is going to publish part 3 of my article which talks about this.  There are a number of threads that discuss this.

Bob and Gary have re-used canisters multiple times without problems.  I’ve refilled a 220 g canister about 4 times so far.  I don’t think they will wear out.  You can get dirt in the Lindal valve which would kill it.  or strip the threads.  I dropped one and dented it so I just recycled it after emptying it.

You have to weigh the canister either when it’s full, or when it’s empty and then add the capacity like 110 or 220 g.  Then, make sure you don’t exceed this.  You can put another ounce in it but if it warms up, it will expand, then burst canister.

[Eugene Hollingsworth]

Jerry, I’m looking forward to part 3 of your article. I had checked out Adventures in Stoving,  YouTube, and other threads- probably missing quite a few.

With the high butane content I might use some kind of thermo feedback if the temps would be down to freezing in the mornings. Excellent articles here’s in BPL to set that up safely.

[Jerry Adams]

we seem to have a flood of articles about canister stoves.  And Jim’s summary at adventures in stoving.

[Greg F]

To burst the Cansister you would need it almost entirely filled with liquid as as long as you have sufficient space for the thermal expansion of the liquid butane.

This is because the maximum pressure of the container provided it has vapour space is the vapour pressure of butane.

And given that the thermal expansion of liquid butane is quite low you only need a small

amount of vapour space to be safe.

In addition Liquid butane is denser than a propane butane mix so if you just limit yourself to the original weight you will have sufficient margin of safety.  Going to 3/4 full provides no additional safety.

Ensure you have a basic understanding of the behaviour of liquids and gases at their vapour pressure as it is what governs the pressure in your Canister and it’s behaviour is not always intuitive.

[David Thomas]

Roger asked me about writing an article about refilling butane-blend canisters.  I’m not sure one can write an article on how to do it 100% safely. I’m pondering an article about how NOT to refill canisters.  As in “Don’t do this . . . ” (because you could blow up in this particular way) and “Don’t do that . . . “(because things could go sideways through. . . ), etc.

>”the thermal expansion of liquid butane is quite low”
I wouldn’t say that.  Organic liquids expand A LOT more than solids do and if you’re filling a refrigerated canister and still want it to be safe in a hot car at >50C, then you’d better never exceed its original fill weight.

Liquid butane is denser than a propane butane mix

True.

“so if you just limit yourself to the original weight you will have sufficient margin of safety.”

Mostly, but not quite.  Since butane has a higher coefficient of thermal expansion than propane, 100% butane will thermally expand slightly more than 80% butane.

“Going to 3/4 full provides no additional safety.”

In spirit, yes.  But attempting to fill to exactly the original weight leaves you potentially with minor weighing errors resulting in a more-than-factory fill.  And there’s that thermal expansion question on butane-rich mixtures.  I want to run the numbers for many different scenarios before saying anything more conclusive, but I’ve run enough to say, “going to 3/4 full provides no additional safety over refilling to 90%.”

[David Thomas]

The first things I’d say to anyone planning to refill canisters is:

Start easy.  Transfer from butane-blend canister to butane-blend canister.

This lets you utilize those 1/4 and 1/2 canisters you keep bringing back from the field.

It also lets you buy a 450-gram canister of butane/propane blend at, say, $8/pound and refill 110-gram canisters that otherwise cost $20/pound for butane.

Always, always, always, mark your canisters with total factory weight when you get home from the store.  In indelible ink.  Even if you never refill them, you can then quickly assess how much fuel remains in each canister after use and you can confirm which ones are 100% fill versus slightly used.

I keep my brand new canisters in one labeled box.  I keep my partials in another.  And any refills are in a third.

Get a good quality transfer valve.  I like the G-works Gas Saver R1.  $29.99 on eBay with free shipping from Korea.  Or $27.99 on Amazon Prime, fulfilled by Amazon.

Always screw a canister into a stove or transfer valve with the canister upright.  Always have the stove valve or transfer valve CLOSED first.

If you start with that limited program (transferring only from partially used to partially used and from large to small, all of iso-butane or propane/butane mixes), you’ll have similar vapor pressures in each canister.  Small temperature differences between your ambient-temp donor canister and your refrigerated recipient canister will provide the pressure difference to push liquid butane from the donor above to recipient below.

If you refill partial butane-propane-blend canisters with lower-pressure 100% n-butane, you need to have a greater temperature difference.  Doable, but I find I have to watch things more closely to avoid overfilling.

And ALWAYS, ALWAYS, ALWAYS weigh the refilled cartridge immediately after refilling.  If you are above the factory weight (maybe 95% of the factory weight), vent butane in a safe manner until you are below the factory weight.

[David Thomas]

If you want to refill with cheaper 100% n-butane from those horizontal canisters sold in Asian groceries, I’d suggest emptying your butane-propane blend canisters (perhaps transferring to other blended canisters).  Then you won’t have that iso-butane or 20% propane remaining and making it harder to get the 100% n-butane into the remaining, higher pressure fuel.

And label them “100% n-butane”.  Because while they’ll be fine for summer use or with Moulder Strips in most winter conditions, you wouldn’t want to grab one for a -10F snow camping trip.  Also, if you’re refiling them repeatedly, again, it is easier to fill a partial butane canister with more n-butane.

I wouldn’t fret about the Lindel valve.  Don’t force things.  Don’t cross thread anything.  Keep things clean (easier at home than in the field).  Be organized.  Keep good notes.  Label everything.  Do only one thing at a time.  Work in a ventilated area.  Consider ignition sources like the furnace or water heater and work way the hell away from them.

[Bob Moulder]

Great advice thus far.

Get a good, small platform scale with at least 1g resolution. For testing stove efficiency (fuel consumption), 0.1g resolution is necessary, so perhaps go ahead and get the higher-resolution scale from the start because you will want to do this at some point.

I have a test canister that I have refilled many, many times, so there’s no telling how long a Lindal valve will last. It is a Primus canister but it comes from the same Korean factory (Taeyang) that makes most of the others. As David says, be careful with the threads and they too will last a long time. Keep the little plastic cap on the canister any time it is not connected to a stove, and keep the stove in a little storage bag to help prevent debris from getting into the jet. A very tiny bit of schmutz anywhere in the system can really ruin your day.

Transferring fuel is actually pretty safe and there is plenty of advice above so I won’t repeat that… Just don’t get lackadaisical when doing it and make sure connections are good and transfer valves are closed before hooking things up.

Cost has not been addressed so I will give you a general idea, keeping in mind that I haven’t purchased new canisters in quite some time… however, IIRC I was paying about $4.95 for 110g canisters and about $6.95 for 220g canisters. The butane tabletop stove cartridges at my local Asian market cost about $1.65 for a 220g container. So you’re looking at roughly 80% savings compared to full-cost standard canisters. (Not counting regional price differences, sales, deals, etc…. this is a ‘ballpark’ figure)

[Jerry Adams]

$5 for 4 butane cartridges – 8 ounces each – at Korean grocery in Portland

I think those are 50% isobutane, 50% n-butane based on the boiling point I’ve measured 20 degree F

My last trip it got to 28 F, stove was a little slow so I used the BIC lighter to warm it a little.  Maybe a reasonable conclusion from this is to not use the cheap butane when it’s going to be cold.

I saw a youtube video where the guy overfilled his canister by an ounce and thought that was really cool.  Then added a comment later that the bottom of the canister pushed out so not such a great idea.  I don’t think you need a margin, you can fill to 100% of rated quantity.  There’s an extra space in the canister.  As long as you carefully measure.  And stay within the 120 F temp limit.  But I underfill by half an ounce or so just because…

[David Thomas]

Jerry: I’m cool with people refilling to save money or to save / fully utilize canisters.

I worry when they hope to get more-than-factory weights into the canister or want to put a “better”, higher-pressure blend into the canister.  If MSR could have safely made a better cold-weather canister while retaining all the safety margins, they would have.  Now we have this reasonable compromise between heavy steel green, Coleman propane canisters (a pound of propane in a pound of steel) and poor-performing n-butane.  And Moulder strips and other tricks let us use those butane-blends to any temperature we want to.

[Paul Magnanti]

PEOPLE SHOUT IN CAPS WHEN WE TALK ABOUT REFILLING CANISTERS!!!!  OMG! THAT’S DANGEROUS!

Luckily, not on BPL, but on many other platforms.

Using power tools, driving, repairing electrical equipment, rock climbing,  handling firearms, etc. can be dangerous too if not done correctly.

But if a person uses the proper precautions, does their research, and follows correct procedure,  filling a fuel canister is safe. As are many of the above activities

Use Hikin’ Jim’s methods.  

Be safe. Follow procedure. Save money. Have fun backpacking.

 

[Edgar H]

Neat!

[David Thomas]

DON’T REFILL YOUR CAR’S GAS TANK YOURSELF!!! YOU COULD PUT DIESEL IN A GASOLINE BY MISTAKE AND STOP IT IN ITS TRACK!!! YOU COULD PUT GASOLINE IN A DIESEL CAR AND DESTROY THE ENGINE!!!  AND IF YOU DON’T CAREFULLY GROUND YOURSELF TO DISSIPATE STATIC CHARGE, YOU CAN IGNITE THE VAPORS LEAVING THE FILL PIPE, THEN SPILL LIQUID GASOLINE AND START A HUGE FIRE – THERE ARE YOUTUBE VIDEOS ABOUT THAT!!!  WHEN YOUR CAR RUNS OUT OF GAS, THROW IT AWAY AND BUY A NEW ONE – THE ONLY SAFE WAY IS TO LET THE MANUFACTURE FILL THE TANK!!!

<sarcasm>

[Bob Moulder]

Think up your own caption….

“Yes, she is permitted to reproduce, unless Darwin gets there first.”

[Jerry Adams]

smoking will not ignite the fumes

lighting the cigarette can ignite the fumes

but I won’t test that

[Roger Caffin]

One thing which has not been emphasised enough so far:
Refill OUTDOORS!

You don’t want a build-up of fuel vapour indoors: that can lead to a fuel/air explosion – and one of those could destroy your house very easily.

Cheers

[David Thomas]

We all know what that “poof” sound, the tingly sensation of a flame front quickly passing between your calves and your jeans, and the smell of burning protein mean, right?

They mean you won’t have to shave your legs that week.

It often also means you now have a glazing project in your near future.

[Roger Caffin]

The glazing project is not so bad. It’s the reroofing project which is more difficult.
Along with the hassles of regrowing your eyelashes.

Cheers

[Eugene Hollingsworth]

wow thanks a lot guys for all the input. That’s a lot of good information and rounds out what I’ve read  at sites like Jim starving adventures. All the constructive posts pretty much resolves my safety concerns.

 

I’ll get the G Works Gas Saver. Which butane adapter do you suggest? I already have the digital scale.

 

[David Thomas]

On eBay, you can get the horizontal butane canister adaptor bundled with the “Gas Saver R1” for an additional $17:

http://www.ebay.com/itm/Butane-Fuel-Canister-refill-Adapter-Converter-/371685923998?var=&hash=item568a351c9e:m:mLI-rt6p_pntodwFh0_eQCQ

Or by itself for $18.64 on Amazon Prime:

[Author]

Posts