Flipfuel

[Tantell]

Hi, I saw these flipfuel devices on Facebook allowing gas to be transferred from one canister to another- are these any good? Or just some dodgy FB advertising?
Cheers

[Tantell]

https://www.amazon.com/FlipFuel-Backpac ... B09NCN8CBR

Example

[headwerkn]

I have one. They definitely work, but you've got to understand what you're doing, the limitations of the process and - yes - the potential to overfill and create a potential danger.

That said, it ain't rocket science... just thermodynamics *snare-cymbal crash*

The Flip-Fuel works as a simple, adjustable connection between two fuel canisters - that's it. There's no intelligence to it. It's not one-way by design - for that you need to engage a little Boyle's Law. Sending canister needs to be warmed up (increasing pressure) whereas the receiving canister aka. the one you're filling up needs to be chilled down to decrease pressure. This way, the gases flow from one to the other.

The 'problem' is that the only way to meter or gauge the filling process is to stop, detach the receiving cylinder and put it on a set of scales to see how much gas has been transferred over compared to your given canister's total 'official' gross weight, using a table like this -> https://i.imgur.com/tszmIsK.png

Overfilling a gas canister is all kinds of stupid for reasons that hopefully don't need to be explained, so therefore anyone sensible will fill a little at a time, carefully measuring between 'squirts', making sure they don't overfill. After a while you do get a sense of how many seconds per gram transfer BUT all the while the pressure differential is dropping as the sending canister cools down and empties, and the receiving canister warms up and fills up.

The reality is that it usually takes a few cycles of warming up supply canisters in the sun etc while the receiving canisters sits in the freezer to actually 'fill up' a canister to within a few grams of its safe maximum capacity. Think 20 mins of effort, not 2. You'll also struggle to fully empty the supplying canisters - even filling into a freezing cold, empty receiving canister, I can never get the last 5-10g out.

Still, if you regularly use gas canisters (especially the small 100g ones that fit neatly into 700ml mugs/billies) it's a great way to save waste and money. Isobutane/propane canisters are exponentially better value the larger size you buy them, so buying a bigger one to refill a smaller canister multiple times will quickly pay for itself. And loads of half-used canisters can be found in the usual places where walkers ditch them before flying off. We were given a couple of shopping bag's full some time ago and I swear that'll keep us going for the next year or more.

So yeah, the unit has well and truly paid for itself As long as you've got a set of reasonably sensitive digital scales and equal measures of patience and commonsense, they're a good thing.

[Tantell]

Thank you for great description. I'd be keen to not have all these half cylenders lying around. It'd be something I'd do at home not on trail so scales are no problem. Thanks for your feedback, might look at one. Cheers

[ggorgeman]

+1 thank you Headwerkn. I did purchase one of the FlipFuel units a while back but haven't used it yet. Your post is a good refresher of the process. Some good Youtube clips on the topic too.

[Tortoise]

Yes, thanks for the details, Headwerkn. Another question, another chance to display my ignorance and confusion.

I've got some 230 gm Gasmate cylinders that I got at a good price. They specify 75% iso-butane + 25% propane. I can't find the mix for Jetboil canisters anywhere, but that could be obvious. It only appears to say isobutane/propane mix, without indicating the ratio. E.g. at:
https://www.jetboil.co.uk/collections/accessories/products/jetpower-fuel

I've got some very empty small Jetboil canisters (I burnt off all the gas at the end, then left the stove turned on for a long time (in a very ventilated area) to make sure none was left. I can't see any problem transferring some from a Gasmate cylinder to a very empty Jetboil one. Can anyone else? What about if there was still a bit in the Jetboil one? The ratios might be different, but I can't imagine they'd be that different. Often I don't need to take a full canister, but am keen to save wastage and $ where I can. So being able to bring a small one up to half or 2/3 full would be very handy. And that would leave plenty of room for me to make errors.

[Kott]

I should get this too....have too many half full canisters everywhere

[headwerkn]

Yes, thanks for the details, Headwerkn. Another question, another chance to display my ignorance and confusion.

I've got some 230 gm Gasmate cylinders that I got at a good price. They specify 75% iso-butane + 25% propane. I can't find the mix for Jetboil canisters anywhere, but that could be obvious. It only appears to say isobutane/propane mix, without indicating the ratio. E.g. at:
https://www.jetboil.co.uk/collections/accessories/products/jetpower-fuel

I've got some very empty small Jetboil canisters (I burnt off all the gas at the end, then left the stove turned on for a long time (in a very ventilated area) to make sure none was left. I can't see any problem transferring some from a Gasmate cylinder to a very empty Jetboil one. Can anyone else? What about if there was still a bit in the Jetboil one? The ratios might be different, but I can't imagine they'd be that different. Often I don't need to take a full canister, but am keen to save wastage and $ where I can. So being able to bring a small one up to half or 2/3 full would be very handy. And that would leave plenty of room for me to make errors.

Firstly, don't sweat the butane/propane mix ratios - it doesn't really matter unless you're chasing maximum performance/efficiency in very cold conditions. Propane works better in colder conditions (lower boiling/vapour point) than butane but is a bit more expensive, which is why companies like MSR and JetBoil feel entitled to charge a premium for "winter mix" canisters of isobutane mix. Gas mixes aren't brand specific, feel free to dump cheap Gasmate gas from Kmart into that fancy little MSR canister that cost $16 originally.

The small 100g JetBoil canisters are easy to work out... an empty canister weighs exactly 100grams, and takes a maximum of 100grams of gas, for a total net weight of 200g when full. If you fill up to around 190-195grams total net weight, you're golden. I have on occasion overshot by a few grams; in that case, you can use the purge button the Flipfuel to dump the excess (do this outside, away from smokers etc. for obvious reasons).

Personally I'd aim to fill as close to full as possible, rather than half or two-thirds full... good gas stove performance relies on decent pressure from the canister itself, which drops noticeably as the canister empties. Also you never know if you'll be stuck out another day or two, if someone in your group needs extra gas.

[Moondog55]

This is the best use of these devices.
Filling these very expensive 100g canisters from a cheaper large can

[Tortoise]

Thanks, Headwerkn. Very helpful!

[Lamont]

Thanks, Headwerkn. Very helpful!

Just fyi-I've had two (re-filled) cans fail on me now-one very recent one-hardly re-filled at all. That is-when the stove was removed the gas just kept coming.
Drained in a blink as it was quite soundless and I didn't realise after taking off the burner. Worth having a listen after you remove the stove.
I believe they are making them more prone to quicker failure.

[Tortoise]

Eek! Thanks for the heads up on that too.

[Lamont]

[ggorgeman]

Thanks, Headwerkn. Very helpful!

Just fyi-I've had two (re-filled) cans fail on me now-one very recent one-hardly re-filled at all. That is-when the stove was removed the gas just kept coming.
Drained in a blink as it was quite soundless and I didn't realise after taking off the burner. Worth having a listen after you remove the stove.
I believe they are making them more prone to quicker failure.

Thanks Lamont, so you're thinking that the re-fill process compromised the valve mechanism of the receiving can? Interesting. I do have the FlipFuel but haven't yet used it.

[headwerkn]

Just fyi-I've had two (re-filled) cans fail on me now-one very recent one-hardly re-filled at all. That is-when the stove was removed the gas just kept coming.

Interesting... and worrying.

I'm not sure how many individual refills I've done to date, would be well over two or three dozen by now, mostly reusing two 100g JetBoil canisters over and over. No leaks, damage to the seals or other failures yet. Only real negative noticed over fresh factory canisters is slightly shorter runtimes, but with deliberate underfilling and sometimes lesser quality gas that's to be expected.

I can't really anything intrinsic in either the FlipFuel or the refilling process in general that would cause premature failure. The valve seal in the canister itself, I can only assume as an intentionally disposable item, was intended to survive dozens of insertions/retractions (of a stove fitting) rather than hundreds or thousands. So in theory at some point a reused canister valve will likely fail, though I would imagine the manufacturers have to design in a pretty substantial safety factor. Similarly, the canisters are filled from the factory through the same hole and valve, so they are 'designed' to 'go both ways', so to speak, if only the one the time.

Thinking of other potential factors: any dirt or particles that get caught in the valve, a damaged FlipFuel itself (rough/poor finished machining in the valve unit) or a duffer original canister?

[Lamont]

Thanks, Headwerkn. Very helpful!

Just fyi-I've had two (re-filled) cans fail on me now-one very recent one-hardly re-filled at all. That is-when the stove was removed the gas just kept coming.
Drained in a blink as it was quite soundless and I didn't realise after taking off the burner. Worth having a listen after you remove the stove.
I believe they are making them more prone to quicker failure.

Thanks Lamont, so you're thinking that the re-fill process compromised the valve mechanism of the receiving can? Interesting. I do have the FlipFuel but haven't yet used it.

Just suggesting take a wee bit of care if you do some refilling and keep an eye on the used can.
Was near a very well known tourist spot recently and the general store had the 200 gm cans for $6 and the bigger ones (500gms?) for $10.
Walk into Anaconda with their prices and it's like -"Come on in and shut the door-deekhead."

[crollsurf]

Actually I've had a fail as well, started refilling and forgot about it. When I used the refilled canister next, my stove was engulfed by flames. Luckily I was able to turn it off before it got too hot.

Can't deny it wasn't user error but learn't my leason. Cost me a new stove. The damaged stove was probably fine, but didn't want to risk it.

[north-north-west]

I've had the valve on a brand new canister stick open after its first use.