Gas canister disposal

[corvus]

Thanks for that link HJ, $37.00 Buy it now price from the same source +$9.00 postage ,may just have to have one of those because at $1.25 Au for 220g Butane it looks good against $7.95Au for 230g of Premium Blend Mix especially with my Stoves with heat exchangers that accept liquid feed.
corvus

[quote=hikin_jim]
I don't know if this is what you meant, but using 100% butane in liquid feed mode won't buy you much in cold weather. There needs to be some propane to pressurize the canister. 100% has to be kept at least 5C, no matter if the canister is right side up or upside down.
[quote]

Thanks for that HJ wont be using them in cold weather and I will use the neoprene insulation sock I made to help retain heat in the canister.
corvus

[hikin_jim]

I don't know if this is what you meant, but using 100% butane in liquid feed mode won't buy you much in cold weather. There needs to be some propane to pressurize the canister. 100% has to be kept at least 5C, no matter if the canister is right side up or upside down.

Thanks for that HJ wont be using them in cold weather and I will use the neoprene insulation sock I made to help retain heat in the canister.
corvus

Ah. Good plan with an inverted canister stove. Inverted canister stoves don't suffer from evaporative cooling to the same degree as right side up canisters. If you start with a warm canister, run it inverted, and insulate the canister, you should be in good shape.

HJ

[Orion]

If I fill to the specified weight, the proportions of gas and liquid should be OK.

That's certainly true if you're using n-butane.

Lower density and higher thermal expansion? Say more about that.

Liquid propane is less dense than isobutane which is in turn less dense than butane. Liquid propane also expands more for a given increase in temperature than the other two. If you fill a canister you need to be sure that as it warms the liquid fuel won't expand to more than the canister volume.

The expansion of these liquid fuels is much more pronounced than you would see with water. From 0.1°C to 50°C, water expands about 1%, not really noticible, but liquid butane and liquid propane will expand 11% and 18%, respectively.

227g of liquid n-butane at 0°C has a volume of 377ml.
If you warm it to 50°C then the liquid expands to 418ml.
227g of liquid propane has a volume of 429ml at 0°C and 506ml at 50°C.

A good website to investigate these properties: http://webbook.nist.gov/chemistry/fluid/

[hikin_jim]

That's very interesting. I hadn't considered thermal expansion or density, but I see what you mean. It's also very interesting that isobutane is less dense than n-butane. I suppose the molecular geometry makes the difference.

I think the issues of vapor pressure, thermal expansion, and density would not cause any problems, if one were to fill canisters to specification. For example, if the canister is 227g size and originally contained 30% propane and 70% butane, my assumption is that refilling with 68g of propane and 159g of butane would be safe. I personally lack the mathematical, chemical, and metallurgical background to calculate the safety myself. I'm assuming that those who created the canister knew what they were doing. So far though, I've played it very safe and have only refilled with n-butane which has a much lower vapor pressure than propane.

HJ

[Orion]

I think the issues of vapor pressure, thermal expansion, and density would not cause any problems, if one were to fill canisters to specification.

But how would you know what was originally in the canister?
And how would you determine what was inside before you started to refill it?

Going with the n-butane seems like the sane thing to do, I mean, assuming one considers refilling sane in the first place.

Is refilling legal? I've never been entirely clear on that. Here in the US there are warnings on non-refillable propane cylinders about huge fines if one transports them after refilling.

[hikin_jim]

But how would you know what was originally in the canister?

A lot of companies post on their website the proportions of the gasses in their canister. Some companies even print them on the side of the canister. I've got a lot of canister gas component fuel ratios posted on my blog. I would not refill a canister with any propane unless I were very sure I knew what the original proportions were.

And how would you determine what was inside before you started to refill it?

If you were refilling with any propane, I would only refill completely empty canisters. Topping off can only be done with n-butane.

HJ

[Orion]

Jim, I have made some measurements and found that the manufacturers are not always telling the truth.
For example, the 80/20 MSR and 80/20 Snowpeak are quite different.

Maybe the difference is not enough to matter though. If you are filling from empty caninsters then perhaps you could be confident.


What is 70/30 anyways? Is that by weight? Volume? Molar concentration??
I'd guess weight, but it would only be an educated guess.

[hikin_jim]

Jim, I have made some measurements and found that the manufacturers are not always telling the truth.
For example, the 80/20 MSR and 80/20 Snowpeak are quite different.

Maybe the difference is not enough to matter though. If you are filling from empty caninsters then perhaps you could be confident.


What is 70/30 anyways? Is that by weight? Volume? Molar concentration??
I'd guess weight, but it would only be an educated guess.

Snow Peak is 85/15 according to their website.

I'm sure that there will be variations from canister to canister. I also am sure that there are safety tolerances that are built into the equation. I know that Kovea makes 70/30 isobutane/propane canisters, but that they're just not allowed in the US. Powermax is 65/35 in the US whereas I've seen it at 60/40 (as printed in the side of the canister) in Great Britain. The US specs are very conservative, no doubt in part due to product liability concerns.

The proportions are by weight. Molar fraction would be an interesting one, wouldn't it?

HJ

[Tony]

This is an interesting thread, for several years now I have been refilling my canisters,(with much care) I have been using 450g canisters to refill std 228g, 100g canisters and 170 Coleman Max canisters I usually use 450g Kovea canisters of 75% Iso-butane 25% Propane mix or 450g Companion canisters which is 44% n-butane, 29% Iso-butane and 27% Propane, and I have never had a problem in winter or the heat of summer.

I have been thinking about making my own mixtures using the cheap n-Butane canisters for the bulk of the refill and Propane for the rest, I would only use these refilled canisters for my liquid fee stoves for winter use only and I cannot see why I would not be able to go up to 40% Propane even for the STD 228g canisters, I yet have to work the canister pressures out.

The Coleman Max canisters I have, both the 170g and 300g do not have any information on them about gas mixtures, I suspect they are the same as what is available in the US 65% Iso-Butane/35% Propane.

The older 228g Kovea canisters, the green ones have the mixtures information written on them 70% Iso-Butane, 30% Propane, the newer Kovea 228g Canisters, the white ones do not have the mixtures ratio information on them, though they do state the canister contains Iso-Butane/Propane mix, the 450g Kovea canisters have 75% Iso-Butane/25% Propane written on them. The MSR canisters are 80% Iso-Butane/20% Propane but they are twice the price of Kovea canisters and I refuse to use them, I also have a STD 100g Coleman canister, the mix is stated as 70%Butane/30% Propane. The JetBoil canisters do not have mixture information.

There are many other brands of canisters available in Australia but they are usually more expensive than Kovea and have less desirable mixtures, The JetBoil 100g canister cost at least $3.00 more than the 228g Kovea canister.

Tony

Edit Coleman Max fuel contains N-Butane not Iso-Butane

[hikin_jim]

Assuming the donor canister had a similar mix of gasses, refilling from one blended canister to another should be fairly safe, particularly if you invert the donor canister and feed liquid to the recipient canister which would give you a consistent blend. It would be pretty tough to get much from the donor to the recipient if you try to feed vapor, so I assume that the transfer is in liquid form.

If prices where you live are similar to the prices near me, buying the larger sizes is almost like getting free gas. The difference in price here between a 113g canister and a 227g canister is typically only $1.00. Another $1.50 or so gets you a 450g canister. Even at those prices, the restaurant industry type 227g 100% n-butane canisters are cheaper still. I assume that they must produce 100 of the cheap canisters for every one bushwalking type canister. Volume production drives down price. Propane, at least near me, can be had fairly cheaply in the 485g canisters or cheaper still in the larger cylinders used for outdoor home cooking. How very inexpensive then if you could fill your own canisters with a 60/40 blend (or similar) of propane and n-butane, a very effective blend in cold weather if you operate your stove in liquid feed mode.

That would truly be lovely, Tony, if you could do the calculations to establish what pressures would be safe.

HJ

[Tony]

That would truly be lovely, Tony, if you could do the calculations to establish what pressures would be safe.

HJ

Hi HJ,

Great debate, I will post canister pressures results when do.

Note, I just check the Coleman Max fuel data sheet and Max fuel uses uses N-Butane. not Iso-Butane.

Tony

[hikin_jim]

Great debate, I will post canister pressures results when do.

Fabulous!

Note, I just check the Coleman Max fuel data sheet and Max fuel uses uses N-Butane. not Iso-Butane.

Yes, Coleman Max ("Powermax" in the US) is n-butane and propane. In the US it's a 65/35 mix. In the UK, according to what is printed with the canisters it's a 60/40 mix. I suspect, based on what Roger Caffin has said his research indicated, that a 60/40 mix may have been available in Australia, at least at one time. I'm not certain we can know for sure exactly what blend was available in Australia.

HJ

P.S. I suppose we could just ask Roger where he got his 60/40 numbers.

[Tony]

Great debate, I will post canister pressures results when do.

Fabulous!

Note, I just check the Coleman Max fuel data sheet and Max fuel uses uses N-Butane. not Iso-Butane.

Yes, Coleman Max ("Powermax" in the US) is n-butane and propane. In the US it's a 65/35 mix. In the UK, according to what is printed with the canisters it's a 60/40 mix. I suspect, based on what Roger Caffin has said his research indicated, that a 60/40 mix may have been available in Australia, at least at one time. I'm not certain we can know for sure exactly what blend was available in Australia.

HJ

P.S. I suppose we could just ask Roger where he got his 60/40 numbers.

Hi HJ,

Yes, the mystery does deepen, when I blew the photo on CCS of the canister up, I think I can read the canister model no. which is 9700A730 the same as mine? which is stated on the Data Sheet as having 35/65 mix ????

I will have to go back and check some old e-mails but I think from memory Roger got the 40/60 from someone at Coleman.

Tony

[hikin_jim]

I'm speculating, but my suspicion is that Coleman marketed two different blends. A more effective 60/40 was available (at least in the UK) outside the US. In the US, a slightly lesser blend of 65/35 was available.

The difference in blends is consistent with other canister available. For example a 70/30 pro/iso blend (Kovea) is available in Australia -- a very nice cold weather blend. No such product is available in the US, the highest being either 70/30 pro/n-butane or 80/20 pro/iso (which have roughly the same vapor pressure). If I were a company like, say, MSR, Brunton, or Jetboil, I would introduce a 70/30 pro/iso blend if there were any legal way to do it, and then market the heck out of it, calling attention to the fact that my particular company has a superior blend. The fact that there are not one but three companies offering 80/20 pro/iso blends and that there are no better blends available, suggests that there is some regulatory impediment. It's probably the US Department of Transportation (DOT) regulations. DOT regulations specify particular vapor pressures at a particular temperature that a canister must be able to sustain. I'm almost sure that DOT regulations must be the reason why no better blends than 80/20 are available in the US. Yes, I am speculating, but it's a fairly informed speculation.

HJ

[Orion]

Snow Peak is 85/15 according to their website.

I meant Jetboil, not Snow Peak, but it's the same point: the 80/20 of Jetboil is not the same as the 80/20 of MSR.

I measured a bunch of canisters about five years ago. At that time it was very obvious that the mixture in Snow Peak was better than the one in MSR and that the Jetboil mixture was superior to both. It's possible that these fuels have changed since then, but at the time both Jetboil and MSR were claiming 80/20 and yet they were obviously quite different. That's why I am skeptical about manufacturer claims.

If you want to calculate the vapor pressure of a pure mixture of isobutane and propane it is very easy to do. The problem is verifying what these canister mixtures really are in the first place.

If I were going to attempt to refill with a more volatile yet uncertain mixture I'd put a gauge on the canister and vary the temperature. But I personally don't see enough upside in refilling to bother with it. The convenience of topping up is pretty minor and the cost savings are lost in the noise when compared to auto petrol and food.

[hikin_jim]

OK, so the specifications on the website aren't exact. So what? The canisters are strong enough to handle the normal range of variations in the stated blends otherwise there would be flaming headlines in the news. The canisters are probably over-engineered if anything. Staying with specified ratios should be well within the canister's capability.

As for cost, each to his own, but it works for me. If I refill with butane, I get the 113g sized canisters for 50 cents each. Think of it this way: I can burn a 113g canister every weekend for six months for $12.00. That's CHEAP. How many weekends can someone go out for $12.00 if buying at retail prices?

HJ

[Nuts]

I might have sparked some of these discussions from this and the other thread. They are just out of interest to me as we wouldn't refill canisters for insurance reasons (same with using cheap, non-compliant chinese stoves).

These are great discussions and worth while considering for the average backyard fiddler (hopefully they don't implode with passion ).

*What about the valves, I read that these may not handle too many refills, how do you know until they leak (if unnoticed I guess the first time will be while alight....)
*I'm still curious what happens with a slow stove, it should have burn't off the gas? or is it just ...slow (ie efficient but wait longer..?)

(I tend to agree there would be more headlines, i doubt the number of people refilling would be huge..)

Back to you, stove freaks :

[South_Aussie_Hiker]

I was told earlier this year by an outdoor shop in Burnie that Kovea no longer supply canisters to Australia.

They said identical canisters to the old light blue Kovea are made under license and rebadged as "Elemental".

I have no idea how true this is, but didn't have any other option as we were off to Frenchman's first thing in the morning. The Elemental certainly seemed fine, but then we didn't have any sub zero temperatures so can't really be sure.

I didn't check the percentage mixes of the three gases

[Tony]

Hi Orion,

The convenience of topping up is pretty minor and the cost savings are lost in the noise when compared to auto petrol and food.

You have made a very good point, the cost of my recent NZ trip was around A$2000 (I am yet to add the bills up), the cost of the gas canister we used was NZ$8. But a $ saved on gas is a $ we can spend on other gear.

Tony

[Tony]

I was told earlier this year by an outdoor shop in Burnie that Kovea no longer supply canisters to Australia.

They said identical canisters to the old light blue Kovea are made under license and rebadged as "Elemental".

I have no idea how true this is, but didn't have any other option as we were off to Frenchman's first thing in the morning. The Elemental certainly seemed fine, but then we didn't have any sub zero temperatures so can't really be sure.

I didn't check the percentage mixes of the three gases

Hi South_Aussie_Hike,

Thanks for that information. I could believe it, my Kovea Supalite stove was branded as a Elemental.

The big worry is that the in a shop I was in last week, the Elemental canisters where more expensive than the Kovea ones.

Tony

[Nuts]

Your right SAH, i actually mean't elemental. They replaced the Kovea branded cylinders a few years back. Same distributor (Grant Minervini in SA) but rebranded, both very similar made in Korea. I wonder why, the only info missing on the new cylinders is the fuel mix %ages... They carry the same warning: 'Do not refill, Do not puncture,even after use.' Interestingly: 'Do not expose to temps above 50c'...

I'm no legal boffin either but these warnings likely also have consequences for any mishap and the outcome for domestic insurance?

[hikin_jim]

What about the valves, I read that these may not handle too many refills, how do you know until they leak

As for valves, I'm not too worried about them. I have never heard of a catastrophic failure due to pressure in a valve. I have seen valves stick, although that is a) rare and b) in canisters that had not been refilled. Lindal valves, the type of valves used in bushwalking type gas canisters, are used in thousands of applications. Spray paint, hair spray, and thousands of other consumer products, all have Lindal valves. They're extremely reliable. Will they wear forever? No. I limit myself to 12 refills per canister.

Think also about this: A 450g canister has a Lindal valve. A 113g canister has a Lindal valve. Generally, a Lindal valve in a 450g canister will get about four times the use of a 113g canister. Filling a 113g canister four times is asking essentially nothing unusual of the valve.

Now consider the Jones family. They like taking their gas Trangia 25 to the beach for the weekend. They like to cook, including meals that need extended periods of low heat. They probably hook up and keep the valve open for long periods of time as they cook. Contrast that to Clive, a solo walker. He just boils a bit of water to prepare his dehy and cuppa. He hooks up and unhooks his stove frequently and uses the stove only in short bursts. Clive unfortunately is an office worker and has children. He can't get away as often as he'd like. In fact, his 227g canister is left over from a trip he took last year, but he's using it this year because it still has enough gas to get a good trip out of it.

So, what's the point? A Lindal valve has to handle everything from heavy continuous use to short but more numerous uses as well as handling sitting on shelves for long periods of time. In other words, this has to be a very robust valve, one that has to take all comers. If it can handle all that, it can handle a few refills.

Now, another thought: Take a look at one of those little clear plastic lighters. That clear liquid in there? It's butane, the same stuff in a bushwalking canister. If that little flimsy bit of plastic can handle the pressures associated with liquid butane, I'm more than confident that a steel canister will be just fine.

No disrespect intended to anyone not interested in refilling, but I've yet to hear of anything that's uncharacteristically dangerous about refilling with butane. With propane? Yes. You'd best be very careful with propane. But refilling blended fuel canisters with straight butane? No. If you're at all intelligent in terms of how you go about it, it can be quite safe.

HJ

[hikin_jim]

Hi Orion,

The convenience of topping up is pretty minor and the cost savings are lost in the noise when compared to auto petrol and food.

You have made a very good point, the cost of my recent NZ trip was around A$2000 (I am yet to add the bills up), the cost of the gas canister we used was NZ$8. But a $ saved on gas is a $ we can spend on other gear.

Tony

And it depends on how frequently one goes on trips. Unfortunately due to work and family responsibilities, I can't go off to the Canadian Rockies for two weeks like I could when I was single and childless. A lot of my trips are short day walks or what I call a "quick overnighters" (a single night out). These trips are typically local.

For example, I drove about 20 minutes to go on a day walk with my wife and daughter last Saturday. Based on the distance and what I paid for petrol at the pump, I spent about $5.00 for fuel for my vehicle. 113g canisters are, oddly enough, also $5.00 where I live. That means that my cost for a canister is 100% of my transportation cost. In other words, I've just doubled the cost of my walk if I want a cuppa.

All right, $10.00 for a bit of family fun is pretty cheap, but I think you can see where I'm going with this. How many "grand" trips does one take a year? I can't take multiple trips where I spend a couple of thousand dollars per year. The great majority of my bushwalking is local. In some respects, comparing the price of a canister of gas to a $2000 trip isn't the most helpful comparison (no offense intended to Tony). For me at least, a comparison that is more relevant is one that compares canister gas to the costs I will incur on a local trip. In the context of frequent trips that cost less than $50.00, a canister of gas that costs $7.50 takes on a different significance.

Anyway, I'm droning on aren't I? Refilling canisters makes sense to me. That and I can't stand paying $5.00 for something that I know very well is only worth 50 cents. Cheap bloke.

HJ

[Orion]

No disrespect taken, Jim. I know you can save money doing this. There are a lot of things like that and it's just personal choice as to whether it is worth the time and effort.

[hikin_jim]

Follow the instructions in these videos at your own risk.

Interesting videos. The first one is a bit troubling in that they wind up putting in more than the original factory weight. I'm not certain that's such a good idea. The first one is also troubling in that you can see a bit of butane escaping, but that shouldn't be too bad if you keep away from heat sources. After all, most stoves when you unscrew them will let a little gas escape.

BTW, the refiling rig I have is much more like a stove. It's made of brass and is quite solid. It screws down onto the fitting just as a stove would.






HJ

[corvus]

HJ your last post sort of answers a question I had
Would this assist the transfer,Donor can in the sun to get warm Recipient can in freezer marry the two and get better result ??
corvus

[hikin_jim]

It depends on the brand of cheap butane I buy. With, one of the brands, all I have to do is hook it up and leave it for a few hours. Gravity does the work (that's on a refill of a same sized canister!). Other brands need a little help. I put the donor canister in warm (NOT hot) water, and I wrap the recipient canister with the freezer gel pack that you see in the photo.

In almost all cases, you leave a few grams behind. For example if I refill a 227g bushwalking canister from a 227g butane canister, the most I'm going to get out of the butane canister is about 224g of gas, unless you really want to faff about with it.

It's a bit trickier if I fill a 113g canister from a 227g canister. I have to stop and weigh things periodically. Of course I can refill two 113g canister from one 227g canister, and on the second refill, I just hook it up and let gravity do the work.

HJ

[michael_p]

Interesting videos. The first one is a bit troubling in that they wind up putting in more than the original factory weight.

Scared me as well. Crazy putting more in than what the can would have had before or been rated for.

Great topic everyone. Well worth the read. Thanks.

[hikin_jim]

Oh, one odd thing I've noticed is that most canisters are slightly overfilled, at least the ones I've seen. I have a fairly sensitive gram scale. When I weigh canisters, a few are dead on the money, but it's more typical to find them a gram or two overfilled. Just an odd tidbit.

HJ

[hikin_jim]

No disrespect taken, Jim.

Thank you for not taking offense. I hope I don't get too passionate about things related to stoves.

...it's just personal choice as to whether it is worth the time and effort.

Agreed. And not everyone is dumb enough, er, intrepid enough to try playing with flammable, explosive gasses like I am.

HJ