Cost of canister gas?

[Huntsman247]

It's rather amusing that this thread started talking about how to refill canisters. Now it's all about buying boxes of them. Lol

[Moondog55]

I'll still be refilling small cans, with 100gram canisters it is the only affordable way to go. In fact I'm willing to swap a new full 230g for 3 empty small ones in good condition because a couple went missing from PV hut while I was out skiing, They were empty perhaps people thought they were doing the right thing by taking home "rubbish"

[CasualNerd]

Mine arrived today, and they look great. Exactly the same strength can as the expensive brands and unless you're camping at -10c I don't see why I'll ever need to spend $15 on a canister of gas again !

[Neo]

My box arrived- so it is legit
Lots of camp cooking ahead!

Quick So did mine this morning. I'm still debating whether or not to get a carton of large canisters for the car picnic bag

MD surely Big W butane or a gas cylinder would be cheaper than hike gas? What stove/s do you use when car camping?

[Moondog55]

A 9kg BBQ cylinder usually but we have always packed a small stove for those times when we find a nice place to picnic but no fireplace to boil the billy or doing so would take too much time or be dangerous because of local conditions

[Mark F]

My box of big canisters (2 boxes of 12) also turned up yesterday.

Mine arrived today, and they look great. Exactly the same strength can as the expensive brands and unless you're camping at -10c I don't see why I'll ever need to spend $15 on a canister of gas again !

Actually these contain the gas blend you would be looking for if the temp is -10.

[north-north-west]

Has anyone tried to use one yet to make sure they seal on the stoves properly? I've heard of issues along that line with cheap canisters.

[LachlanB]

I thought most canisters were all the same these days, and you were equally likely to get seal problems with premium ones? Certainly, the only time I've had a seal problem was with an expensive Optimus canister.

[Moondog55]

Has anyone tried to use one yet to make sure they seal on the stoves properly? I've heard of issues along that line with cheap canisters.

I've been using them for years now, ever since I bought out the stock at Geelong K-Mart years ago, no problems at all. There shouldn't be; after all they all come from the same factory in Korea

[CasualNerd]

Actually these contain the gas blend you would be looking for if the temp is -10.

I was reading something about the pressure not being as good at colder temps compared to a brand with a higher percentage of propane. So when using these (upright, no preheat) at colder temps (like -10c) the propane would get burnt first leaving the isobutane which might then lack the pressure to get enough fuel to the burner. It makes sense in my mind if the boiling point of isobutane is -10c and the boiling point of propane is -40c. I can't remember where I read it, maybe that's wrong or just pseudoscience ?

Has anyone tried to use one yet to make sure they seal on the stoves properly? I've heard of issues along that line with cheap canisters.

I just put one on to check and it seals fine on an optimus stove.

... the only time I've had a seal problem was with an expensive Optimus canister.

Likewise, but with a JetBoil canister

[Mark F]

I was reading something about the pressure not being as good at colder temps compared to a brand with a higher percentage of propane. So when using these (upright, no preheat) at colder temps (like -10c) the propane would get burnt first leaving the isobutane which might then lack the pressure to get enough fuel to the burner. It makes sense in my mind if the boiling point of isobutane is -10c and the boiling point of propane is -40c. I can't remember where I read it, maybe that's wrong or just pseudoscience ?

Because of pressure limitations with disposable canisters 25% propane is about as much as can be safely put in the blend. In upright stoves the propane is burnt off preferentially (the butanes are also burnt) and the propane % in the canister drops. At about 30-50% full the propane is largely exhausted leaving the canister less able to handle low temps without the use of something like a Moulder Strip (search the bpl site for lots of info). The standard sub zero option is to use a stove able to handle a liquid feed via an inverted canister where the low boiling point of the propane drives the feed of liquid gas to the stove. The liquid feed is in largely in same proportions as the canister (25% propane, 75% butane) so the propane is not exhausted preferentially and the canister works until almost empty. See https://bushwalkingnsw.org.au/clubsites/FAQ/FAQ_GasStoves.htm for everything you ever wanted to know about gas stoves.

[pulseevents]

I have been using an adapter to fill cans from a 9kg bottle for a while now with no problem. I use scales to measure weight of gas so not to overfill but the only thing i have noticed is my stove uses it a little quicker. If using it in cold areas you can just pour some water over it to warm it or wrap your hands around it to increase preasure when gas gets low.

[Moondog55]

I have been using an adapter to fill cans from a 9kg bottle for a while now with no problem. I use scales to measure weight of gas so not to overfill but the only thing i have noticed is my stove uses it a little quicker. If using it in cold areas you can just pour some water over it to warm it or wrap your hands around it to increase preasure when gas gets low.

Interested in which adaptor you used and from whence you purchased

[johnrs]

Heh Pulsevents
Are you refilling lightweight canisters from LPG cylinders??
This could end with a big bang and a large fireball??
John

[Mark F]

While I am happy refilling canisters with fuel blends similar to their original contents, I believe it is irresponsible to advocate refilling canisters with 100% propane. My suggestion is DON'T DO IT!

A 100% propane canister is under about twice the pressure compared to a 20/80% propane/iso-butane blend at the same temperature. The pressure increases rapidly with temperature. You won't catch me refilling lightweight canisters with pure propane - that is why 100% propane and lpg comes encased in heavy steel with safety valves. Accidentally leave a 100% propane lightweight canister in your car on a hot summer day and you may find your car's interior has been restructured when you return.

100% propane has a pressure of 149 psig at 32 deg C (https://www.elgas.com.au/blog/1969-how-much-pressure-is-in-lpg-propane-cylinders-in-what-state) while the maximum charging pressure for registration under the DOT standards is 150 psig https://bushwalkingnsw.org.au/clubsites/FAQ/FAQ_StovesTech.htm#Hot.

[Moondog55]

But Mark BBQ gas simply isn't pure propane, it's 50/50 Propane/Butane.
The same as Auto LPG. No matter what BS the suppliers tell you it's a mix here in Victoria.
The mix is why I object to paying so much for BBQ gas when auto LPG is $1:40 a kilo [ $0:70 a litre]

[Mark F]

But Mark BBQ gas simply isn't pure propane, it's 50/50 Propane/Butane.
The same as Auto LPG. No matter what BS the suppliers tell you it's a mix here in Victoria.
The mix is why I object to paying so much for BBQ gas when auto LPG is $1:40 a kilo [ $0:70 a litre]

Why then does the Elgas site https://www.elgas.com.au/blog/492-what-is-lpg-lpg-gas-lp-gas clearly state that "In Australia, LPG is propane" and then continues by noting that in NZ it is a mix of propane and butane.

A useful list by country is provided here https://www.elgas.com.au/blog/1972-lpg-contains-which-gases-gases-present-in-lpg-gases-used

Can you provide me with a reference from a serious authority for your statement that LPG is a 50/50 blend?

[Moondog55]

Because I expect them to lie. No Mark I cannot.

[Mark F]

Because I expect them to lie. No Mark I cannot.

There is no benefit to Elgas by lying that I can identify especially as they acknowledge that lpg has various compositions in different countries. One only tends to lie if there is a perceived benefit in doing so.

Even if the composition was a 50/50 blend then it would still push the pressure in the canister to about 30% higher than design - in my view an unacceptable risk.

[Moondog55]

www.environment.gov.au/system/files/res ... paper5.pdf

I knew I'd find it somewhere So it appears I am both right and wrong. In the city and major towns it will be 50/50 and up to 60% propane but in outlying areas it will be more likely to be 100% propane. According to the bloke I just spoke to [ No I didn't write his name down] at the RACV the closer you are to Melbourne or the Hume the more likely you are to get the blend and much more likely to get more butane in the mix in summer than in winter.
But I do know that BBQ gas and Autogas are the same gas as I see them fill the 200l tanks from the same hose on the tankers every day or two just down the road from me. Butane is so much cheaper than Propane normally and the profit is so high I expect the suppliers to cheat these days as there seems to me that there is no real control on suppliers any more.
On the vapour pressure issue what is the difference between a 50/50 mix and the 30/70 mix I have here now? I note tho that the cans I just bought say 30/70 also

[GPSGuided]

On the vapour pressure issue what is the difference between a 50/50 mix and the 30/70 mix I have here now? I note tho that the cans I just bought say 30/70 also

Out in the market place, small portable cans are known to have up to 30% propane mix, none higher. As such and without knowing the precise engineering spec of those containers, it’d be crazy to try to go higher in a home mix. If you read the vaporisation temp-pressure graph of propane, pressure will go exponential beyond room temperature. As such, the risk of spontaneous rupture will increase dramatically in outdoors conditions. Fact is, without full control of the whole manufacturing process, home cocktails are best to stay well below that 30% mark as you have no verification of the precise mix of your source gas liquid.

Of course, Darwin Award awaits for anyone who cares to tempt fate.

[pulseevents]

Mmm. Was told some years back when i waz in nsw that bbq gas was a butane.propane blend so now in good old brisvagas thought i might check. So far both elgas and supagas tell me that in qld its all 100% propane so that may be the end of my refilling days.
Back to looking at buying a msr multifuel. Gives me options to save some $ using liquid as swell..

[Mark F]

I believe you can calculate the pressure of a blend by summing the results for each gas component vapour pressure at temperature x times the percentage - please let me know if this is wrong (roger). Using the graph from zenstoves below (values below extrapolated from the graph):

At 30 deg Celsius propane is at 160 psi, iso-butane 60 psi, n-butane 40 psi. So pure 100% propane has a pressure of 160 psi, 50/50 blend has between (80 + 30 = 110 or 80 + 20 = 100) depending on the mix of butanes.
A 30/70 propane/iso-butane blend gives 48 + 42 = 90 so pressure is 22% higher for the pure propane. But you cannot be sure of the of the actual propane/butane blend in the first case but can rely to some extent on what is shown on the lightweight canister where, if anything, the propane value will be exaggerated. Expediency suggests that you should assume a value closer to 100% propane than to 50%.

At 40 degrees this blows out to 208 psi for 100% propane, 108 + 40 = 148 psi for the 50/50 blend (+40%) and 62 + 56 = 118 psi for the 30/70 blend, so 100% propane pressure is +76% and +25% against the 50/50 blend. The 50/50 blend is now at the top working pressure for DOT standards and 40 degrees is not hard to reach in a hot car. Also note that the percentage differential increases as the temperature increases.

Remember also that you are not only dealing with canisters that are stored/in transit but also with canisters sitting under a lit stove. The relative volume of liquid gas in the canister has little (read no) effect on the vapour pressure. Plus the "ouch" test for canister temperature kicks in at about 45 degrees.


http://zenstoves.net/Canister/GasCanisterFuelVaporizationPressureVsATM+PSIBasic2.png

[GPSGuided]

Info on partial gas pressure - 'Total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture'.
https://en.wikipedia.org/wiki/Partial_pressure

[Moondog55]

Well at least i'm not contemplating refilling Flyspray type butane canisters, it seems that a lot of people do as that seems to be the most common adaptor on AliExpress

[Mark F]

I think you have it the wrong way around. The flyspray type butane cartridges are used to refill the normal lindal valve canisters using that adapter. For warm weather the flyspray cartridges provide the cheapest fuel available given that you can buy a 4 pack for about $5-$6. With the current Gasmate prices for the 450g canisters mean you are paying $2 for a full refill of a 230g canister with winter quality gas compared to about $1.25-$1.50 for a summer n-butane refill.

[Moondog55]

Mark I am talking about adaptors that sell on AliExpress, specifically to refill small picnic canisters of butane directly from big LPG cylinders
I wouldn't attempt that myself but apparently people in China do. I have been using butane refills on my 230g Lyndal canisters for ages for summer use but it's just as easy to use a remote stove directly from the flyspray cans with a good adaptor now
EDIT
To paste the link to this adaptor
https://www.ebay.com.au/itm/Propane-Ref ... Sw5cNYULNC

[ribuck]

Has anyone actually lit one yet, to confirm that they're not just full of water?

[Moondog55]

Naturally.
They appear to burn the same as any of my other canisters have, although I haven't frozen one to check cold weather start-up

[GPSGuided]

I haven't frozen one to check cold weather start-up

Don’t do too much of that or you’ll burn off all the propane before you actually need them out there.