Juggling Fuel Canisters [Archive]

nsherry61

04-16-2018, 14:44

I just got back from a cross-country trip with my brother-in-law that left me with a box of mostly empty large (16 oz) fuel canisters that he could not take back with him on the plane. What to do? I have no use for the large canisters, but I like free fuel . . . so, I ordered a "fuel canister refill adapter" from Amazon for about $14 (https://www.amazon.com/Jeebel-Camp-Butane-Canister-Adapter/dp/B07989SFTN/ref=sr_1_1?ie=UTF8&qid=1523907356&sr=8-1&keywords=fuel+canister+refill+adapter), figuring it might be kinda funky, but I could probably manage, somehow to fill up my empty and partially empty small (4 oz, 110 g) fuel canisters from the partially full large ones.

WOW! It was way easier than I expected. So I thought I'd share what I did in case some others like the idea of reusing canisters, filling small canisters with the much less expensive fuel bought in quantity in the large canisters ($1.75/oz vs $0.75/oz), or people that don't wont to carry any more fuel than necessary, so they can transfer fuel to or from canisters to get the exact amount of fuel they want for a given trip.

The whole process was super easy.
1) Attach the adapter between the two canisters you are moving fuel from and to.
2) Place the canister you want to fill on the bottom in a pan of ice water (see attached picture)
3) Pour boiling water into the bottom of the upside down canister you want to transfer fuel from.
4) Let the canisters sit for a minute or two to cool in the ice water and warm from the hot water.
5) Open the refill adapter to fill (or partially fill) the lower canister.
6) Unscrew the canisters from each other and the adapter.
7) Go backpacking

42473

A few notes:
1) The 110 g canisters can easily be filled to about 130 g with no apparent issues. (Edit . . . NOTE: Overfilling canisters beyond the original gas weight is surely unwise and may be dangerous, therefore, if your canister is overfilled, reverse the process described above and transfer a little of the gas back out of the overfilled canister to retain a robust safety margin.)

2) The canisters being emptied only emptied down to about the last 10 g of fuel in most cases, since the fuel is transfering via a pressure gradient that requires pressure in the upper canister to be higher than the lower canister. With patience, you may be able to do a little better than I did, but you will never get every last gram of fuel out of the upper canister until you puncture is to let out the last remaining pressure before putting it in the recycling.

3) Having a kitchen diet scale (https://www.amazon.com/Etekcity-Multifunction-Stainless-Batteries-Included/dp/B0113UZJE2/ref=sr_1_1_sspa?s=home-garden&ie=UTF8&qid=1523903493&sr=1-1-spons&keywords=kitchen+scale&psc=1) (~$15) is super helpful in knowing how much fuel is in each canister and how much you have transfered. The same type scale is considered mandatory gear for most backpackers to be able to weigh all their other gear. I write the fuel weight on each canister with a sharpie so I know how much fuel I'm taking whenever I grab one to use, and I can grab one with the amount of fuel I want for a given trip. Just subtract the empty canister weight from the total weight to calculate available fuel.
- 110 g canisters weigh about 100 g empty
- 220 g canisters weigh about 150 g empty
- 550 g canisters weigh about 200 g empty

dcdennis

04-16-2018, 14:48

This thread's got me all.....gassed up.

dcdennis

04-16-2018, 14:49

Your link doesnt go to amazon though. Just to an adventure blog. Whats the device you used?

FreeGoldRush

04-16-2018, 15:00

This might earn someone a Darwin Award.

nsherry61

04-16-2018, 15:36

This might earn someone a Darwin Award.
Obviously you've never worked at a propane filling station. You'd be hard pressed to get into trouble with these simple devices.

Try this link (https://www.amazon.com/Jeebel-Camp-Butane-Canister-Adapter/dp/B07989SFTN/ref=sr_1_1?ie=UTF8&qid=1523907356&sr=8-1&keywords=fuel+canister+refill+adapter) to the gadget I used, although, it looks like there are several similar options if you search for "fuel canister refill adapter"

HooKooDooKu

04-16-2018, 15:41

1) The 110 g canisters can easily be filled to about 130 g with no apparent issues.

And you can light the fuse on a stick of dynamite and hold it in your mouth "with no apparent issues"... until it becomes an issue.

somers515

04-16-2018, 16:52

Cool tip - thanks Nsherry61! I use up my old canisters trying out new backpacking recipes but this is a neat idea too.

nsherry61

04-16-2018, 17:03

And you can light the fuse on a stick of dynamite and hold it in your mouth "with no apparent issues"... until it becomes an issue.
Yep. That being said, it is the vapor pressure of the gas, determined by the temperature of the gas, not the quantity, that determines the pressure in the canister. That is actually why the canisters work as well and consistently they do even with a huge range of different gas quantities in the canisters.

Adfischer

04-16-2018, 17:10

I'm no going to criticize anyone for trying to say money, so do as you see fit. However I personally would never do that because I would be afraid of leaks. Those Lindal valves are cheap and not designed for multiple uses. Last thing I want on the trail is to get to camp and discover all my fuel has leaked out (or worse). I have also heard there is a DOT regulation that prohibits transporting refilled canisters but I dont have anything I can cite on that. I have a pretty healthy respect for highly flammable gasses so I'll stick with purchasing new ones.

nsherry61

04-16-2018, 17:51

. . . I have also heard there is a DOT regulation that prohibits transporting refilled canisters but I dont have anything I can cite on that. I have a pretty healthy respect for highly flammable gasses so I'll stick with purchasing new ones.

Good thoughts.

To my knowledge, DOT doesn't have anything to say about refilled vs. new canisters. Transportation of all backpacking stove fuels (except maybe wood) are highly restricted by DOT, esbit tablets less so than gasses. I am not aware of any differences between pressurized canisters, refilled pressurized canisters and/or liquid fuels. They are all dangerous if not handled responsibly. Frankly, not unlike filling your car.

As for reliability of the Lyndal valves, they are clearly simple, designed for single use, and highly effective. Some people may use up a canister by installing and removing their stove 5 to 10 times. Someone else may do so, especially with larger canisters, dozens of times. They are designed to be used safely significantly more than most of us will ever use them for an average 110 g canister. Over many years and much abuse, I've only ever had a Lyndal valve fail in extremely cold conditions whereby it didn't reseal after the stove was removed. Never any real danger, just leaking gas, well away from any potential sparks or open flames. Never leaking except immediately after removing the stove. And frankly, I got it to seal by putting the stove back on and removing it again.

As for refilling canisters, given how simple and well sealed the refill system is, the filling process probably isn't as dangerous as lighting my kitchen gas stove. As for valve reliability, I would probably only refill canisters a few times and not treat them as infinitely refillable. BUT, you are NOT adding extra pressure to the cartridges unless you are using gas mixes different than they originally contained, e.g. filling from a propane bottle instead of another butane/isobutane/propane mix with a max of 20% propane.

Adfischer

04-16-2018, 18:09

I found the video below which is talking about refilling DOT39 cylinders. That is where the DOT reg I mentioned came from. I'm not sure camp stoves are considered DOT39 so it may apply, but them seem like they are even thinner and less durable than the 1lb mentioned in the video. You are also (hopefully) not refilling from a 20lb propane tank! I'll stick to the manufacturers cartridge, but I think you are wise to only use them a few times after refilling.

https://youtu.be/g2_GhyAw3vM

Adfischer

04-16-2018, 18:11

I'm not sure camp stoves are considered DOT39 so it may apply....

I meant to say it may NOT apply...

nsherry61

04-16-2018, 18:24

I believe the DOT39 refers to relatively high pressure canisters which our backpacking canisters are not. And, in refilling backpacking canisters, we are playing with relatively small pressure differentials compared to propane (slightly less than 1/3 the pressure). There is a reason our canisters are limited to only 20% propane with the rest being butane or isobutane.

You realize that people walk around every day with little plastic butane cartridges in their pants with buttons that accidently release bits of gas now an again and most of us don't think twice about this.

Kaptainkriz

04-16-2018, 18:30

4eyedbuzzard

04-16-2018, 19:10

The reason for only filling a small canister with 110 grams of fuel (or any canister to its designed weight) is to allow for headspace in the canister so that there is room for gas expansion. A small portion of the liquid fuel vaporizes and becomes a gas under pressure in the canister. Headspace is this area, the part which is not filled by the liquid fuel. If overfilled (more than 110 grams) you have exceeded the designed headspace in the canister. If you overfill too much, and don't leave enough headspace for the designed amount of gas, you could get hydrostatic pressurization (because liquids do not compress) and catastrophic failure of the canister. Which could be exactly as it sounds - catastrophic.

nsherry61

04-16-2018, 19:46

. . . Beware, the 110g mass of fuel is referenced against a safe volume and the potential expansion of the liquid when the canister heats up due to weather or use. A canister full when cold, may be overfull when hot. . .
I think my previous statement about overfilling a canister was written in a way that can easily be misunderstood. I had no intention to encourage overfilling, but rather just to point out that doing so was possible without any obvious indication of it. MSR claims to fill the canisters with 117 g. I know people that have regularly overfilled their canisters without problem. But, a preponderance of caution would suggest that filling them with more than about 117 g would not be as safe as limiting their fill to 117 g.

nsherry61

04-16-2018, 20:02

The Adventures in Stoving web site has a significant write-up about refilling canisters (https://adventuresinstoving.blogspot.com/2012/01/gas-canister-refilling.html) if anyone wants to read even more . . .

rusane

04-16-2018, 20:13

My guess is its not 100% effective. Factor in this loss, the energy to make ice and boil water, and the time I could have spent drinking, and it’s a net loser for me.

cmoulder

04-16-2018, 20:15

I do a lot of refilling of my own canisters with leftovers / butane. Beware, the 110g mass of fuel is referenced against a safe volume and the potential expansion of the liquid when the canister heats up due to weather or use. A canister full when cold, may be overfull when hot. When the expanding liquid (not gas) has nowhere to go, it will deform the canister and possibly rupture. Large propane tanks have a gauge with temp on it to help prevent over filling.
42480

I think my previous statement about overfilling a canister was written in a way that can easily be misunderstood. I had no intention to encourage overfilling, but rather just to point out that doing so was possible without any obvious indication of it. MSR claims to fill the canisters with 117 g. I know people that have regularly overfilled their canisters without problem. But, a preponderance of caution would suggest that filling them with more than about 117 g would not be as safe as limiting their fill to 117 g.

I agree with Kaptainkriz about NOT overfilling, but the other concerns about transferring fuel from one container to another are indeed vastly overblown. This is, overall, a very safe procedure. The amount of gas released when decoupling is about as much as (or less than!) you'd see when filling a butane cigarette lighter... truly minuscule.

Also, I have a certain Primus canister that I have refilled many dozens of times (using cheap tabletop stove butane cartridge fuel) just to see how many cycles a Lindal valve can stand, and it is far, far more than a few times. I'm still using the darn thing and it just won't quit.

lonehiker

04-16-2018, 21:12

My guess is its not 100% effective. Factor in this loss, the energy to make ice and boil water, and the time I could have spent drinking, and it’s a net loser for me.

Drink while making the ice and boiling the water. Then, continue to drink while transferring the gas makes for a net gain...

cmoulder

04-17-2018, 06:20

My guess is its not 100% effective. Factor in this loss, the energy to make ice and boil water, and the time I could have spent drinking, and it’s a net loser for me.
You only need heat up the donor can with hot water from the kitchen faucet. Room temp for the recipient can is cool enough... no need for ice. This way it will take a couple of cycles heating the donor can to top off the recipient can, and you have to check weight with a good scale (accurate to 1g) but that's about it.

It is 100% effective, and worth it to me to spend 83¢ vs $4.95 for a canister of fuel. Indeed, not at all practical on a thru but totally doable for many other trips.

meat803

04-17-2018, 08:01

[QUOTE=Adfischer;2204805]I found the video below which is talking about refilling DOT39 cylinders. That is where the DOT reg I mentioned came from. I'm not sure camp stoves are considered DOT39 so it may apply, but them seem like they are even thinner and less durable than the 1lb mentioned in the video. You are also (hopefully) not refilling from a 20lb propane tank! I'll stick to the manufacturers cartridge, but I think you are wise to only use them a few times after refilling.

The investigators found the 20lb tank was leaking and ignited by a heater. The fire had ZERO to do with the refilled smaller tanks. What a weak example to use that realistically wasn't connected at all. The tank was stored in a confined space with a leaky valve and not turned off. You would think they would come up with a legitimate example or evidence rather than cheap scare tactics. It wouldn't surprise me if some 1lb propane tank lobbyist snuck this law into a larger bill to maximize profits. They do it all the time without legitimate debate.

Starchild

04-17-2018, 08:26

There is a version of that valve that will allow you to (presumably) vent the lower can gas while filling liquid from the upper allowing a much faster fill at the cost of a little gas. IDK if it works well but reviews were positive when I looked at it months ago.

Adfischer

04-17-2018, 08:26

The investigators found the 20lb tank was leaking and ignited by a heater. The fire had ZERO to do with the refilled smaller tanks. What a weak example to use that realistically wasn't connected at all. The tank was stored in a confined space with a leaky valve and not turned off. You would think they would come up with a legitimate example or evidence rather than cheap scare tactics. It wouldn't surprise me if some 1lb propane tank lobbyist snuck this law into a larger bill to maximize profits. They do it all the time without legitimate debate.

The confined space was definitely a contributor. I don’t believe anyone snuck something in a law. I have seen enough of those brand new 1lb propane cylinders leak after a single use to know they are not reliable and to me refilling is not a good idea. I have been a firefighter for 30 years and have seen some pretty crazy stuff. People doing stuff they thought was safe for years only to have something go wrong just one time. It’s given me a healthy respect for things like highly flammable gases that make me not want to step outside the manufactures specifications.

Sent from my iPhone using Tapatalk

rocketsocks

04-17-2018, 10:42

Id really like to see someone juggle a lit canister stove, a porcupine and a sopping wet puffy jacket.

LittleRock

04-17-2018, 14:44

Eh, I'll stick with my current approach of giving my nearly empty canisters away to LD hikers or dropping them in the hiker box at a hostel on the last day of my trip.

Maui Rhino

04-17-2018, 19:36

Thanks for sharing. I might look into doing this.

Back at the start of this century, I spent 3 years living in a homestead with no running water or electricity. I used propane Coleman lanterns for lighting, and kept a fleet of 20 one pound cylinders. Each week, I would refill them from a 20# tank. I always did my refilling outside, and very carefully checked each cylinder after filling them by sight, sound, and soapy water if suspect. Occasionally, a canister would leak after filling, and I would discard those, but I usually was able to refill them 15-20 times without issue. After 20 refills, I replaced them anyway. I did have 3 lanterns fail and start jetting fuel out by the plastic shutoff valve, but not because of any fault of the refilled canisters. YMMV

TNhiker

04-17-2018, 20:07

Id really like to see someone juggle a lit canister stove, a porcupine and a sopping wet puffy jacket.

Oh?

a challenge, eh?

BuckeyeBill

04-17-2018, 20:30

Very interesting thread. You have the side of this works well for me vs. the side that this is dangerous. The DOT 39 cylinders discussed in the video are made of a slightly thicker metal, as they are capable of holding slightly higher pressures that ISO butane canisters, so you have to wonder if it is dangerous to refill DOT 39 cylinders, how safe is to refill canisters.

There are tools (https://www.rei.com/product/813638/jetboil-crunchit-recycling-tool) available that allow you to bleed off, then puncture canisters to mark them as empty. Some people use nails or screwdrivers to accomplish the same thing, but I am not sure this is the safest way to do this. You have to wonder that any canister that can be punctured by basically a can opener, is it safe to refill them without exactly knowing the internal pressure of either canister? There are other ways that I can save money while hiking so I can either use the canister until it is completely empty or giving it to someone in need and opening a new canister. I may change my thinking on this if there were a blow off valve that would release at a pressure below the limits of the canister's safety rating.

Jetboil now has a mini scale (https://www.rei.com/product/127967/jetboil-jetgauge-canister-weight-scale) (weighs 2.5oz.) you can carry with you to determine how much fuel is left in your canister. While it works best with Jetboil canisters, it can be used with other manufacturers canisters.

Of course the standard "This is only my opinion" applies.

Brutalguyracing

04-17-2018, 23:43

Adfischer

04-18-2018, 09:32

This
42504

Exactly. Not worth the risk for the little amount of money saved. If you are going to do this, at least cook away from others so you only injure yourself!

nsherry61

04-18-2018, 10:02

. . .You have to wonder that any canister that can be punctured by basically a can opener, is it safe to refill them without exactly knowing the internal pressure of either canister? . . .
Two points to think about on this one:
1) You realize we are talking about essentially the same gas most of us carry without concern in our pocket in a fairly easily crushed plastic pressure vessel called a bic lighter, don't you?
2) Unlike pressurized gas canisters for SCUBA diving or welding where the gas is not liquid and pressures are very high, the gas pressure in our little backpacking fuel canisters is essentially independent of how much fuel is in the canister because the fuel is at an equilibrium gas/liquid state with pressure dependent on temperature, not the amount of fuel. If you add more fuel, you would increase the pressure except increased pressure drives the equilibrium to more liquid which reduces pressure, so the pressure is stable at whatever the vapor pressure of the fuel is at a particular temperature. So use the fuel the canisters are designed for, not other fuels with higher vapor pressures. This is basic physics, which if you haven't had or don't remember, may not make sense, but is why these canisters and stoves work in the first place.

Really and truly, filling you car up at the gas station is probably more dangerous than transfering butane between canisters. And cooking with propane, or natural gas for that matter, is significantly more dangerous, but, most of us do both without much thought because we are familiar with the practices.

rocketsocks

04-18-2018, 10:15

This
42504holy yield point Batman, watch it, she’s gonna blow!

FreeGoldRush

04-18-2018, 10:24

This
42504

Exactly. The Darwin Award is earned when someone heats the upper can too much without having any idea how much pressure is present. It's not like these cans are precision manufactured and designed to last a while. Someone will be using a gas stove to heat the boiling water. They'll pour it onto the can that ruptures right next to the open flame. There is a big difference in understanding the science that makes it work and doing the things to make the process safely repeatable.

After all, BASE jumping is perfectly doable and safe until someone overlooks a minor detail.

FreeGoldRush

04-18-2018, 10:30

2) Unlike pressurized gas canisters for SCUBA diving or welding where the gas is not liquid and pressures are very high, the gas pressure in our little backpacking fuel canisters is essentially independent of how much fuel is in the canister because the fuel is at an equilibrium gas/liquid state with pressure dependent on temperature, not the amount of
The difference is that my SCUBA tanks are inspected and (used to be) hydrostatically tested every 5 years. It may be high pressure, but the container is 1) Designed for the pressure, 2) Tested to ensure it is safe, and 3) Always used exactly as designed.

You are correct that this refilling process can be entirely safe with the proper equipment. Cheap, disposable fuel canisters do not meet that requirement, in my opinion.

nsherry61

04-18-2018, 10:44

. . .After all, BASE jumping is perfectly doable and safe until someone overlooks a minor detail.
A good comparison. Many people love BASE jumping. Some people would never dream of doing it because of the perceived risk. . . kinda like backpacking too.

Although J-walking is probably a better one. You may never J-walk because of the potential risk or just because you always follow the letter of the law. Kudos to you. Most of us choose to j-walk at times because we decide the risk of breaking this rule is small and the reward of saving a few steps or a few seconds of time is worth the small risk.

Life is a risk. Backpacking is a risk. Among the things we do in day to day life and backpacking, I would suggest that reasonable and informed refilling and using of backpacking fuel canisters is NOT one of the riskier things we do. And, being able to adjust the fuel level in a canister for a particular trip may appeal to some people while saving a few dollars or being less wasteful will appeal to others.

Your choice. Please, don't be too self righteous condemning me for mine.

FreeGoldRush

04-18-2018, 10:48

so the pressure is stable at whatever the vapor pressure of the fuel is at a particular temperature. So use the fuel the canisters are designed for, not other fuels with higher vapor pressures. This is basic physics, which if you haven't had or don't remember, may not make sense, but is why these canisters and stoves work in the first place.
.

This is all correct. And if you pour boiling water onto the fuel canister and it is not properly releasing pressure then the liquid and gas both heat up. The pressure rises. They were not manufactured to be safe at 212 degrees Fahrenheit without an ability to release pressure. One cannot measure the pressure or be confident it is releasing correctly, so how can this possibly be safe?

FreeGoldRush

04-18-2018, 10:51

Your choice. Please, don't be too self righteous condemning me for mine.
It was never my intention to indicate that you personally should not do this. The discussion is simply interesting and I have a different opinion. My opinion is that others should not be instructed to do this, but I'm not upset in the least that you disagree.

nsherry61

04-18-2018, 10:57

This is all correct. And if you pour boiling water onto the fuel canister and it is not properly releasing pressure then the liquid and gas both heat up. The pressure rises. They were not manufactured to be safe at 212 degrees Fahrenheit without an ability to release pressure. One cannot measure the pressure or be confident it is releasing correctly, so how can this possibly be safe?
I don't know what temperature the canisters are supposed to be safe to. I doubt you do either. Given that, it would be really stupid to place the canister in boiling water. But, a few tablespoons of boiling water on the base is not heating the canister anywhere close to boiling. And, as was noted earlier in the thread by cmoulder, a person far more experience than I am in the reuse of canisters, and the use of canister stoves for that matter, if you are uncomfortable pouring a bit of boiling water onto the base of a canister, hot tap water is plenty to generate the pressure differential needed to drive the fuel flow.

Adfischer

04-18-2018, 11:01

...... Please, don't be too self righteous condemning me for mine.

I dont think anyone is condemning you, others just have a different opinion. My opinion is you can do whatever you want with your stove canisters. You think its perfectly safe, I think it is not. We can agree to disagree.

Where I have an issue with what you are doing is if you use your refilled canisters near others. I personally do not want to be near someone that I believe may be creating an unsafe condition and putting me or my kids at risk. It only takes one mistake or one defect in a canister that is exaggerated by a refill to be catastrophic.

FreeGoldRush

04-18-2018, 11:05

I don't know what temperature the canisters are supposed to be safe to. I doubt you do either. Given that, it would be really stupid to place the canister in boiling water. But, a few tablespoons of boiling water on the base is not heating the canister anywhere close to boiling. And, as was noted earlier in the thread by cmoulder, a person far more experience than I am in the reuse of canisters, and the use of canister stoves for that matter, if you are uncomfortable pouring a bit of boiling water onto the base of a canister, hot tap water is plenty to generate the pressure differential needed to drive the fuel flow.

I'd say that a little warm tap water reduces the risk substantially. Its not as hot and there is no open flame nearby.

cmoulder

04-18-2018, 13:21

I dont think anyone is condemning you, others just have a different opinion. My opinion is you can do whatever you want with your stove canisters. You think its perfectly safe, I think it is not. We can agree to disagree.

Where I have an issue with what you are doing is if you use your refilled canisters near others. I personally do not want to be near someone that I believe may be creating an unsafe condition and putting me or my kids at risk. It only takes one mistake or one defect in a canister that is exaggerated by a refill to be catastrophic.

lol, talk about hyperbole...

Nothing to worry about. Even if it really were as dangerous and wildly irresponsible as you imagine it to be, the number of people who refill canisters is very, very small. Better to worry about drunken yahoos in public campgrounds.... or that drive to the trail head. :-?

reppans

04-18-2018, 17:16

Thank you for posting this - I got the pricier G-Works Gas Saver+ version from Amazon last week in the interests of bringing my old Jetboil back into service. Hated the 'primary battery' problem of always needing to carry a spare canister - now with the ability to 'top-up' I can go back to a single canister.

FWIW, my '+' version has a neat little vent button to release the lower canister's built-up gas pressure (as it fills) so it can accept more liquified fuel. Should be the same as working the pressure relief valve while refilling the Coleman 1lb propane tanks - basically allowing a full top-up without needing to heat/cool the delivery/receiving tanks (or at least as much).

The investigators found the 20lb tank was leaking and ignited by a heater. The fire had ZERO to do with the refilled smaller tanks. What a weak example to use that realistically wasn't connected at all. The tank was stored in a confined space with a leaky valve and not turned off. You would think they would come up with a legitimate example or evidence rather than cheap scare tactics. It wouldn't surprise me if some 1lb propane tank lobbyist snuck this law into a larger bill to maximize profits. They do it all the time without legitimate debate.

Yeah, that was a pathetic example used in that video. However, while the explosion had nothing to do with the refilled 1lb propane tank(s), it was related to act of refilling.

The refill adapter was left screwed into the 20lb tank and that piece allows the 20lb tank's twist valve to operate (i.e. flow gas manually). Without the refill adapter in place, the 20lb tank's twist valve would have been rendered idiot proof and useless - twisting open or closed would have no effect on gas escaping. But yeah that example reminds me of a guy trying to filling a 1gal gas can from a poorly modulating pump handle (ie, the ones that act like on/off switches).... while smoking a cigarette.

Is the refilling of canisters dangerous? It sure could be. But if you understand what you are doing, the physics behind it, how the equipment works, and follow some pretty obvious safety precautions, then the risks are perfectly manageable and people have been doing this for decades in the RV world. If you don't... then obviously, stay far away from the practice.

JMHO/YMMV and all.

Adfischer

04-18-2018, 17:39

lol, talk about hyperbole...

Nothing to worry about. Even if it really were as dangerous and wildly irresponsible as you imagine it to be, the number of people who refill canisters is very, very small. Better to worry about drunken yahoos in public campgrounds.... or that drive to the trail head. :-?

You call it hyperbole, I call it safety. No argument though on the drunken yahoos! (Or druken yahoos with a refilled canister!! :eek:)

nsherry61

04-18-2018, 18:29

You call it hyperbole, I call it safety. . .
I still want to know if you j-walk or not? ;-)

The psychology of risk acceptance and risk aversion are always interesting.

There is no doubt that I am more risk averse as I have aged. But clearly, I am still more risk accepting than many, maybe because of my perspective from years of marginally irresponsible risk taking and a strong background in statistics and probability.

That being said, reusing single use canisters is NOT a high risk proposition. . . BASE jumping is more so . . . although I still think it would be really cool to do.

BuckeyeBill

04-18-2018, 21:28

Two points to think about on this one:
1) You realize we are talking about essentially the same gas most of us carry without concern in our pocket in a fairly easily crushed plastic pressure vessel called a bic lighter, don't you?
2) Unlike pressurized gas canisters for SCUBA diving or welding where the gas is not liquid and pressures are very high, the gas pressure in our little backpacking fuel canisters is essentially independent of how much fuel is in the canister because the fuel is at an equilibrium gas/liquid state with pressure dependent on temperature, not the amount of fuel. If you add more fuel, you would increase the pressure except increased pressure drives the equilibrium to more liquid which reduces pressure, so the pressure is stable at whatever the vapor pressure of the fuel is at a particular temperature. So use the fuel the canisters are designed for, not other fuels with higher vapor pressures. This is basic physics, which if you haven't had or don't remember, may not make sense, but is why these canisters and stoves work in the first place.

Really and truly, filling you car up at the gas station is probably more dangerous than transfering butane between canisters. And cooking with propane, or natural gas for that matter, is significantly more dangerous, but, most of us do both without much thought because we are familiar with the practices.

As to your first point, I don't carry a butane style lighter. I use a Zippo and have for years. I do this because there was an incident where a guy was killed when he blew half of his chest off. Investigation finally showed he carried a Bic lighter I his shirt pocket and while welding over his head and a spark hit the lighter causing it explode. In fact I do not allow any of my employees to have a Bic on their person while working. I have made it a disciplinary offense if they do. After 90 days I buy them a Zippo and can of lighter fluid. I am not this way to be a prick, I just don't want anyone of them injured. I hired them because they showed themselves to be the best at what they were hired to do.

On the trail I carry a handheld piezo igniter.

As to your second point, canisters contain ISO-butane with a boiling point 10.9* F. That's why they preform poorly in colder temperatures. ISO-Butane canisters do not draw liquid from the bottom of the canister as they are normally used with stoves in the upright position and the stoves can't burn it in a liquid form. When you invert a canister it is putting liquid into the bottom canister. Without knowing the pressure of either canister, there still presents a danger of overfilling. Liquid Propane gas has such a low boiling point (-44*) that they can draw from the bottom of the tanks. All propane tanks in use today except DOT 39 cylinders, have a valve system that prevents overfilling.

As to the post about buying the "+" valve, I think if you read the description again you will see that it is an air bleed to allow the transfer to take place.

nsherry61

04-18-2018, 22:59

. . . ISO-Butane canisters do not draw liquid from the bottom of the canister as they are normally used with stoves in the upright position and the stoves can't burn it in a liquid form. . .

Yes, liquid fuels does not burn. Vapors burn, whether candles, Zippo lighter fluid, butane, or propane, only vapors burn, not fluids.

. . . Without knowing the pressure of either canister, there still presents a danger of overfilling. . .
There is always risk of overfilling. As discussed earlier in this thread, there needs to be some head space in the canister to allow for a small amount of expansion of the liquid as temperatures increase. As to pressure, we can always calculate the pressure in any canister if we know the temperature regardless of the amount of fuel in the canister because it is dependent almost entirely on the vapor pressure of the fuel, not the amount of fuel. So, make sure you can shake your isobutane canister and hear it sloshing around in the head space. If there is not sloshing, it is overfilled. It is highly recommended to weigh the canister accurately and make sure the canister plus fuel weight is the same or less than when the canister was new.

. . . Liquid Propane gas has such a low boiling point (-44*) that they can draw from the bottom of the tanks. . .
Not quite. Boiling point has nothing to do with drawing from the bottom of a canister or not. You can draw liquid from the bottom or gas from the top of either propane or butane. The principals for butane and propane are essentially identical. The difference being that propane has much higher vapor pressure so it needs stronger tanks, and yes, the release valve allows the tanks to be filled with less care and still be certain there is head space for the liquid to expand into as a full tank warms up.

Obviously, you are a person that is not comfortable with the risks of pressurized fuels in your pockets, and that is fine. The welder explosion story is one that's been around for as long as butane lighters have been around. (https://www.snopes.com/fact-check/the-lighter-side-of-death/) I don't think I would carry one if I were a welder. That being said, a welding spark (i.e. hot piece of metal) burning though I bic lighter still will not ignite the gas in most cases as the spark is no longer hot enough to ignite the gas by the time it has melted through the plastic. Check out this video (https://www.youtube.com/watch?v=cKovmwf2kgM) if you want a fun example with lighters and hot metal.

reppans

04-18-2018, 23:32

...As to the post about buying the "+" valve, I think if you read the description again you will see that it is an air bleed to allow the transfer to take place.

This is a quote from the description which I admittedly did not previously read, but surmised from its function and my experience from refilling the 1lb propane tanks. It does seem to function just as I have described above... please explain what you think its function is?

...Flow ceases as pressure equalizes. The Air Vent releases the bottom canister's air (air + vaporized fuel), letting more liquid flow from the top canister. Gas Saver Plus (with its Air Vent) captures more gas than Gas Saver R1.

BuckeyeBill

04-19-2018, 00:16

Your are correct when you said there is a risk of overfilling. But you are willing to risk filling to the point of no head space just to save money. As I said earlier I can save money other ways and use canisters to empty or give it to someone in need. Yes stoves can't burn liquid, but that is why boiling points are so important. Once outdoor temperatures drop below 10.9*, canisters begin to perform poorly. That is why stoves like the WhisperLite Universal can work with either white gas or canisters be cause it has a remote hookup and you can invert the canister. This pumps liquid fuel to the stove and it turns to a vapor at the burner.

The welder explosion story is one that's been around for as long as butane lighters have been around.

Seems you believe a folklorist on the internet over a OHSA report and yes I read the OSHA findings in a business related magazine. The one I was referencing occurred in California in 2004 while I was living in San Diego. It happen in an auto repair shop while using a MIG welder.

reppans

04-19-2018, 00:25

This a good video describing the pressure vent method for refilling the 1lb Coleman 1lb tanks without needing to heat/chill the tanks. The physics are similar except that butane should be more temperature sensitive than propane, and also that you cannot simultaneously release pressure while transferring liquified gas due to the single valve.

https://youtu.be/fD1CmorB_qM

Leo L.

04-19-2018, 03:08

Following this discussion, I'm just wondering:
When you've connected an almost empty and a half empty canister by means of said valve, what can go wrong if you heat up the stuff to, say, boiling water temperature?
There is plenty of space in the whole system for expanding liquid gas.

While I personally have high respect for pressurized gas systems (generally speaking), there was a time at the beginning of my engineering career when we had to design and manufacture generator sets that included heat recovery for off-grid Alpine huts.
We were tied to liquid gas as primary energy due to its low risk in pretty much any circumstance. Much lower risk than most other liquid or gas primary energies.

For the described scenario of refilling stove canisters, you just need to stay outside so any leakage can evaporate, and stay away from any source of ignitions, then you would be pretty safe IMHO.

cmoulder

04-19-2018, 08:04

1) If you WEIGH the canisters with a good scale and can do basic arithemetic, there's no chance of overfilling.

2) Even if you do overfill, very soon after you open the valve that condition will be relieved. Still highly discouraged, however, because of the very real risk of storing an overfilled canister in a hot place. So don't overfill, EVER.

3) I suppose I should not even mention how to wet prime a butane-fueled canister stove in the winter. :D

Adfischer

04-19-2018, 08:22

I still want to know if you j-walk or not? ;-)

The psychology of risk acceptance and risk aversion are always interesting.

There is no doubt that I am more risk averse as I have aged. But clearly, I am still more risk accepting than many, maybe because of my perspective from years of marginally irresponsible risk taking and a strong background in statistics and probability.

That being said, reusing single use canisters is NOT a high risk proposition. . . BASE jumping is more so . . . although I still think it would be really cool to do.

I try not to J-walk, but I have been known to run with scissors and not waiting an hour to swim after I eat.

Sent from my iPhone using Tapatalk

Sarcasm the elf

04-19-2018, 09:35

nsherry61

04-19-2018, 10:14

Maybe we should start a thread about "questionable" practices with stoves that work well with reasonable and responsible caution . . . and other stupid butane tricks . . . just for kicks on this wet snowy spring morning.

Cooking in tents, especially with liquid fuels like this thread (https://www.whiteblaze.net/forum/showthread.php/55724-Cooking-inside-tent)?
Winter stove heat recapture techniques like this thread (https://www.whiteblaze.net/forum/showthread.php/122352-frezzing-water)?
Wet priming a butane stove?

What other highly function "advanced" hacks do we have up our sleeves that might make our mom's squirm a little?

cmoulder

04-19-2018, 10:46

You forgot to mention winter stove heat recapture techniques. https://whiteblaze.net/forum/images/smilies/biggrin.gif

Ah, yes, my refined version of the "Alpine Bomb" which is, in fact, extremely safe?

How about warming a canister by holding a Bic flame to the base? Warming up a canister at 5°F by licking it?? :D

Closest I ever came to disaster with a stove was with an XGK in a tent vestibule at -33°F in the Adirondacks. The o-ring between the fuel tube and pump had stiffened up in the extreme cold and there was a huge puddle of raw naphtha beneath it while the stove was roaring along at full plasma blast setting. Fortunately I smelled the fumes and shut down the stove before the vapors had a chance to ignite, but I am sure my friend and I were a bee's weenie away from getting seriously burned, or worse.

reppans

04-19-2018, 11:30

You forgot to mention winter stove heat recapture techniques. :D

I'm interested - I use my alcohol stove as a personal heater (Palmer furnace). Also cook inside my tent in foul weather (modular floorless mid). Also drink and clean my pots, utensils, hands, body, etc with the fuel (Everclear).

Adfischer

04-19-2018, 11:45