How to determine how much fuel is left in your canister

[oldwetherman]

I just saw this on the BPL website. I doubt that the author would mind me sharing it on Whiteblaze.
http://www.backpackinglight.com/cgi-...=884545#884545

[rocketsocks]

beats the shake test.

[Singto]

Good stuff and as posters in the thread stated, I'd refrain from scoring any type of tubular structure, especially trekking poles. I like to place glow in the dark fingernail polish on most of my items to make them easier to find at night and to mark them as my property.

[perrymk]

If one doesn't carry poles here is a light option I came up with a few years ago.

[rickb]

Cool.

I am new to canister stoves, and end up throwing out the partials.

Question: Does the last ounce of fuel in a canister boil water as fast as the first ounce of fuel?

[ThinAirDesigns]

Cool.

I am new to canister stoves, and end up throwing out the partials.

Question: Does the last ounce of fuel in a canister boil water as fast as the first ounce of fuel?

Can't speak to all stoves (though I suspect they are the same), but my MSR Reactor burns nearly full bore to the end. This will vary a bit based on operating temperature though.

Also, I built a 99 cent adapter to refill my partials and also save 75% on my fuel.

[Tundracamper]

Simple and clever. Need to be able to accommodate for any variations with an adjustable pole - but that should be doable.


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[750ml]

How about a displacement test? Some cooking pots have markings stamped on them. Fill pot to a predetermined level and see how far the water level goes up with an empty tank vs a full one. I haven't tried this, but it might just work.

[4eyedbuzzard]

How about a displacement test? Some cooking pots have markings stamped on them. Fill pot to a predetermined level and see how far the water level goes up with an empty tank vs a full one. I haven't tried this, but it might just work.

The net weight of fuel in a small canister is 100 grams in a canister that weighs 100 grams empty. So you're looking at a pretty small difference in displacement - .1 liters from full to empty. I think it would be difficult in the field to differentiate anything more than perhaps 1/4, 1/2, 3/4 full etc.

[750ml]

The net weight of fuel in a small canister is 100 grams in a canister that weighs 100 grams empty. So you're looking at a pretty small difference in displacement - .1 liters from full to empty. I think it would be difficult in the field to differentiate anything more than perhaps 1/4, 1/2, 3/4 full etc.

Well heck, back to the shake test then.........

[Heliotrope]

Can't speak to all stoves (though I suspect they are the same), but my MSR Reactor burns nearly full bore to the end. This will vary a bit based on operating temperature though.

Also, I built a 99 cent adapter to refill my partials and also save 75% on my fuel.

Thinair, can you elaborate on your refill adapter?


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[4eyedbuzzard]

Can't speak to all stoves (though I suspect they are the same), but my MSR Reactor burns nearly full bore to the end. This will vary a bit based on operating temperature though.

Also, I built a 99 cent adapter to refill my partials and also save 75% on my fuel.

Thinair, can you elaborate on your refill adapter?


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Exactly how many canisters does one have to go through in a year that the small savings of refilling vs. buying canisters for hiking becomes a real issue? What is saved? A few dollars per canister before considering the cost of the refill adapter? You still have to buy the refill butane, and typically it is n-butane, rather than an isobutane/propane blend which will perform better in cold temperatures. If I hiked all summer and used a small canister per week, I'd save $3 per week net on fuel, or $40 for the summer. I don't see where it is worth the time involved plus the associated safety risks. I weigh my partial fills and use them for overnights/weekends, and once really low when car camping or when testing trail meal recipes.

Anyone considering refilling DISPOSABLE isobutane canisters should read these threads http://adventuresinstoving.blogspot....r-warning.html and http://adventuresinstoving.blogspot....refilling.html and then proceed at their own risk.

Quickly summarized - potential problems (many dangerous) including one's not mentioned in the linked page:

1) Even IF you eliminate all the other safety concerns below, these canisters and especially their valves are not designed for repeated and prolonged use. Typically, 100 grams of fuel (small 4oz canister) will boil 12 liters under optimum conditions. So, that's 48 liters for the largest (16oz)canisters available that use this type of valve(Lindal), or maybe 100 connect/reconnect cycles if you boil 1/2 liter per meal and disassemble the canister from the stove each use. I'm sure the valves are designed and tested for much more frequent use AND abuse, likely by factors of 1000's of times or more, because that's how important safety is when dealing with flammable/explosive gases. But as with anything else, they are designed to be as economical as possible to manufacture while fulfilling their designed purpose. And their purpose is NOT to be repeatedly used beyond their designed life, which is one time use. They are designed to be safe and function with the normal contamination and wear expected from their one-time designed usage, but the more you reuse them the more they wear and the more contamination (such as minute particles of dirt) wind up in the seal and valve assembly.

2) Refilling with propane/LP gas, or any mix of fuel that creates vapor pressure greater than the design pressure rating of the canister, could result in failure of the valve or canister itself. 100% propane will create pressures approximately 3 to 4 times those that the typical 80/20 or 70/30 isobutane/propane blend creates in the sealed canister. Note the thickness of steel, construction of valve and fittings, pressure relief valve, etc. on a propane/LP tank vs. the rolled edge seam, thin wall steel, and Lindal valve on a canister. Enough said.

3) Control of filling - manufacturers precisely control the amount of fill to ensure adequate empty expansion space in the filled canister. Failure to do so could result in a catastrophic hydrostatic failure of the canister. And does anyone know the other process controls they undoubtedly use while filling to ensure product safety/reliability?

4) Safety controls. What happens if a bad leak develops during refilling? What about fire suppression and emergency response? Add the possibility of static spark during refilling, and thus the need for proper bonding and grounding regarding the refilling process. How about a small leak you didn't notice, with isobutane now slowly filling the trunk of your car as you drive to the trailhead? Seriously, there is enough explosive potential in a small canister to kill you. People have died from small stove canister explosions!

5) Unknown quality of refilling devices/components. Things like quality of the machining of threads, seals, and others. A lot of the refilling parts on ebay, et al, come from unknown manufacturers and origins. With translated instructions from foreign languages that read like a fortune cookie.

6) Availability of refill gas. Most of these adapters connect an n-butane canister to an isobutane/propane blend canister. You are refilling with fuel that doesn't work very well in temps below 40°F.

[Heliotrope]

Exactly how many canisters does one have to go through in a year that the small savings of refilling vs. buying canisters for hiking becomes a real issue? What is saved? A few dollars per canister before considering the cost of the refill adapter? You still have to buy the refill butane, and typically it is n-butane, rather than an isobutane/propane blend which will perform better in cold temperatures. If I hiked all summer and used a small canister per week, I'd save $3 per week net on fuel, or $40 for the summer. I don't see where it is worth the time involved plus the associated safety risks. I weigh my partial fills and use them for overnights/weekends, and once really low when car camping or when testing trail meal recipes.

Anyone considering refilling DISPOSABLE isobutane canisters should read these threads http://adventuresinstoving.blogspot....r-warning.html and http://adventuresinstoving.blogspot....refilling.html and then proceed at their own risk.

Quickly summarized - potential problems (many dangerous) including one's not mentioned in the linked page:

1) Even IF you eliminate all the other safety concerns below, these canisters and especially their valves are not designed for repeated and prolonged use. Typically, 100 grams of fuel (small 4oz canister) will boil 12 liters under optimum conditions. So, that's 48 liters for the largest (16oz)canisters available that use this type of valve(Lindal), or maybe 100 connect/reconnect cycles if you boil 1/2 liter per meal and disassemble the canister from the stove each use. I'm sure the valves are designed and tested for much more frequent use AND abuse, likely by factors of 1000's of times or more, because that's how important safety is when dealing with flammable/explosive gases. But as with anything else, they are designed to be as economical as possible to manufacture while fulfilling their designed purpose. And their purpose is NOT to be repeatedly used beyond their designed life, which is one time use. They are designed to be safe and function with the normal contamination and wear expected from their one-time designed usage, but the more you reuse them the more they wear and the more contamination (such as minute particles of dirt) wind up in the seal and valve assembly.

2) Refilling with propane/LP gas, or any mix of fuel that creates vapor pressure greater than the design pressure rating of the canister, could result in failure of the valve or canister itself. 100% propane will create pressures approximately 3 to 4 times those that the typical 80/20 or 70/30 isobutane/propane blend creates in the sealed canister. Note the thickness of steel, construction of valve and fittings, pressure relief valve, etc. on a propane/LP tank vs. the rolled edge seam, thin wall steel, and Lindal valve on a canister. Enough said.

3) Control of filling - manufacturers precisely control the amount of fill to ensure adequate empty expansion space in the filled canister. Failure to do so could result in a catastrophic hydrostatic failure of the canister. And does anyone know the other process controls they undoubtedly use while filling to ensure product safety/reliability?

4) Safety controls. What happens if a bad leak develops during refilling? What about fire suppression and emergency response? Add the possibility of static spark during refilling, and thus the need for proper bonding and grounding regarding the refilling process. How about a small leak you didn't notice, with isobutane now slowly filling the trunk of your car as you drive to the trailhead? Seriously, there is enough explosive potential in a small canister to kill you. People have died from small stove canister explosions!

5) Unknown quality of refilling devices/components. Things like quality of the machining of threads, seals, and others. A lot of the refilling parts on ebay, et al, come from unknown manufacturers and origins. With translated instructions from foreign languages that read like a fortune cookie.

6) Availability of refill gas. Most of these adapters connect an n-butane canister to an isobutane/propane blend canister. You are refilling with fuel that doesn't work very well in temps below 40°F.

Very good points, thank you.


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[Heliotrope]

Just looked at an MSR small canister and it actually has markings that correspond to empty, medium and full levels when the canister is immersed in water.


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[Venchka]

Same for the 8 oz. size too. That might be worth the extra cost of the MSR fuel.
Thanks!

Wayne

[slbirdnerd]

How about a displacement test? Some cooking pots have markings stamped on them. Fill pot to a predetermined level and see how far the water level goes up with an empty tank vs a full one. I haven't tried this, but it might just work.

I believe MSR (the red ones) canisters actually have markings on the canister to accomplish this. But you need a pot big enough float it in, so I do mine at home in a big bowl in the sink. Off the top of my head, I'd say the markings are something like 1/4 inch apart for Full, Half, and Empty.

[squeezebox]

Might float it in the next stream you come across.

[Venchka]

The 4 oz & 8 oz sizes fit in my pot.
Go to the MSR page for canisters. The markings are clearly shown in the photos.
I'll do the same with the Primus canisters from Walmart and my digital scale.
Thanks for the tip.

Wayne


Sent from somewhere around here.

[Bark]

Fantastic! Thank you!!

[colorado_rob]

Unnecessary to float them or anything like that. Once you get used to using canisters, it only takes a short while, all you have to do is to shake them and you pretty much know how much is left. Or you also know just from the time you have used them. A small one last me 6-7 days (in a jetboil, doing 2-3, 2-3 cup heats every day), a larger one, twice that. when I shake them and I feel nothing sloshing inside, that means I have only a couple heats left.

It's really simple.