Need to refill small gas cylinders?

[Orion]

Hiking Jim, I weighed one of those Jetboil canisters, along with a new Snowpeak and MSR canister. They all looked pretty nearly identical from the outside.

Full weight without the caps (which weighed 2.4g each):

366.5 SnowPeak
374.8 MSR
379.1 Jetboil

Jetboil claims 356g for the gross weight. A bit off, I'd say.

I don't have empties, but subtracting off the nominal net weights (220, 227 and 230g) gave these values for the empty canisters:

147.8 MSR
146.5 SnowPeak
149.1 Jetboil

All essentially the same. This fits your idea that they all use the same metal container.
And it looks like Jetboil needs to update their website.

[hikin_jim]

Hiking Jim, I weighed one of those Jetboil canisters, along with a new Snowpeak and MSR canister. They all looked pretty nearly identical from the outside.

Full weight without the caps (which weighed 2.4g each):

366.5 SnowPeak
374.8 MSR
379.1 Jetboil

Jetboil claims 356g for the gross weight. A bit off, I'd say.

I don't have empties, but subtracting off the nominal net weights (220, 227 and 230g) gave these values for the empty canisters:

147.8 MSR
146.5 SnowPeak
149.1 Jetboil

All essentially the same. This fits your idea that they all use the same metal container.
And it looks like Jetboil needs to update their website.

Interesting. I too picked up some canisters over the weekend and weighed them. The 220 to 230 g sized canisters all weigh just slightly less than 150 g when empty. There's a 3 or so gram range. I used the same brands as you did, but I also added Optimus and Primus which are available at stores where I live.

I also notice that around the valve area, below the lip, there is a slight ridge of metal. All five of the brands I sampled had that same protrusion on the canister.

I also picked up some 100 to 113 g sized canisters of the same brands but with one additional brand, Gasone. After adjusting for the varying weight of the fill, all of the canisters come in around 100 g empty. Again there's maybe a 3 or so gram range. The variations in weight span the brands. In other words, one brand doesn't uniformly have all the canisters in the low (or high) end of the range.

All the same caps. All the same shape. All the same weight. All the same protrusion below the lip of the valve assembly. All made in Korea. Not definitive, but it is consistent with the idea that all of the major gas brands, at least the ones available near me, are made in the same place (except Coleman as previously noted which is made in France). I'm sure there are exceptions, particularly in Asia, but all of the canisters available in my area appear to be made by the same manufacturer.

The interesting thing is that the stated fill weights vary by 10g depending on the brand. Actual fill weight vary even more, about 13g. This would tend to indicate to me minor variations in fill weight are either a) not significant or b) these canisters are far stronger than are strictly speaking required.

HJ

[Orion]

This would tend to indicate to me minor variations in fill weight are either a) not significant or b) these canisters are far stronger than are strictly speaking required.

I think both are true.

They have to leave enough room for the liquid to expand and still not fill the canister or even fill it so high that some liquid fuel might start bubbling up through the stove. So a little extra isn't going to be an issue. It's more of an economic concern.

The required burst pressure is about 250 psig. That corresponds to a 20/80 mixture at about 80°C. If I read the discussion of Roger Caffin's test correctly, he heated a 30/70 mixture to just below 100°C before the canister failed. The pressure right before it blew apart was probably in excess of 350 psig.

[hikin_jim]

HJ That has been my understanding as well, most of the worlds supply of canister gas for bushwalking and climbing comes from a single factory in Korea

Curious, I asked a contact at MSR. I basically got a "no comment; I can't tell you" kind of an answer. Interesting.

HJ

[Moondog55]

I'm thinking that perhaps my scales need to be recalibrated. An MSR canister I topped up with the dregs of another one [ I had two canisters each I thought 1/3rd full] just popped in exactly the same way when the day topped 41C here. I have no idea how hot it was in the room where I keep my gear but as the house is airconditioned probably no warmer than 32. We were on the other side of the house and we both heard it "Pop"

[hikin_jim]

It shouldn't be sensitive to a few grams difference. I'm suspecting that recalibrating your scale won't make that difference -- but I'm assuming that your scale won't be off by more than a gram or two.

Very interesting. What were the mixes contained in the "donor' canisters?

HJ

[Moondog55]

The MSR was refilled using another MSR canister, I may have made a mistake; I may actually have weighed incorrectly.
I did write the mass on the canister before and after topping up tho but when I filled this one I shoved the recipient can in the freezer and it was quite a hot day so I may have inadvertently over-filled. If so then I made the same mistake with the first can even tho my scales said I had only added 100 grams
The scales are accurate +/- 0.1g but the zero point may have wandered a little, but as you say that shouldn't matter

[Orion]

"as the house is airconditioned probably no warmer than 32"

LOL

[Orion]

Moondog, I had been tempted to suggest that you could have made a weighing error. But you were adamant about the accuracy of your scale so I resisted. Now it sounds like you aren't really sure how much fuel is in the canister?

Did you reweigh the one that "popped"?

I have a question about refilling. How do you monitor the weight? Do you disconnect/weigh/reconnect repeatedly throughout the refilling process?

[Moondog55]

Given the information that it was difficult if not almost impossible to overfill using this method I simply weighed before and after. And I haven't yet put the one that popped on the scales. As it is now well below 42C I'll see if I can do that today
But according to my scales I only added enough fuel to take it back to factory weight.
That was ~ 32C in the back room which we didn't have the head turned on; in the living room it was a nice cool, temperate, comfortable 26

[Orion]

I'm curious to hear what it really weighs, and what the empty weighs once you've safely discharged it.

[hikin_jim]

I did a bit of digging. I found this about Taeyang Industrial Co. Ltd. of Korea:

Taeyang Ind. is the largest portable butane gas cartridge maker in the world, dominating around 70% of global market share as well as 80% of domestic market share as of 2009. Equipped with advanced facilities covering everything from cartridge printing and coating to gas charging, the company exported its butane gas and cartridge more than 50 countries under the brand name 'SUN'.

Korea’s domestically produced portable butane gas cartridge, now the world’s best, can be used for portable gas stoves and torches. Customized to our clients’ needs, we produce the best quality products and export it to about 50 countries worldwide, including Japan, the United States, Europe and Southeast Asia. [emphasis added]

Sounds like we have our prime suspect as to who it is that produces canisters for all the major brands except Coleman.

HJ

[skibug]

Hi all,

In regards to refilling gas canisters, I have received some interesting info about the Festiva 220g gas cartridges, marketed by Woolworths supermarkets in Australia (and also, I gather, sold in New Zealand). They are mainly red and white, and labelled "Butane Gas", but with a smaller heading "Premium ISO Butane mix". Following an email inquiry, I received the following from Rob Owens (Product Manager) from AHM, the manufacturers (or wholesalers, not sure):

Property IsoButane n-Butane Propane Other

Mixture (by volume) 30 - 35% 65 – 70% 1 – 2% Below 2%

Any one know what (sea level) boiling point this would result in? I'm guessing -3 or -4 degrees celsius, which means for ski tourers at around 1800 metres, -6 to -8 degrees (due to altitude/air pressure effects). For me, and I imagine for most backcountry skiers, this is very useable, as temperatures below -8 in Australia are generally infrequent, and if I know it's coming I'll cook late afternoon/early evening before it gets that cold; or plan to be in a hut; or use canister warming strategies. They would probably be fine for just about any Blue Mountains winter night as well, I imagine. One downside with these is that they are $7-50 for four, around double what you pay at K-mart/Bunnings/etc for the straight Butane, but hey, at less than $2 to refill a medium sized cartridge, it's not of consequence. Perhaps sometime after Easter (end of summer/camping season for most) they might come on sale? if so, I'd stock up with a dozen or so, which would last me a year.

Hope this helps the refillers,

Skibug

[skibug]

Sorry guys, that table did not format properly (it looked fine in the editor). Here it is again:

Isobutane 30-35%
n-Butane 65-70%
Propane 1 to 2%
Other below %2

Skibug

[icefest]

It seems they have the same manufacturer as the campmaster cartridges.
They are $1.10 each at Masters: https://www.masters.com.au/product/9000 ... s-220g-4pk

[Nuts]

I can't imagine -8c skibug. Performance still seems to take a plunge in cold weather, the canisters themselves appear to freeze over quicker than the squat cans. A good 3 season option in the mountains, maybe better if decanted into squat cans.

[keithy]

One downside with these is that they are $7-50 for four, around double what you pay at K-mart/Bunnings/etc for the straight Butane, but hey, at less than $2 to refill a medium sized cartridge, it's not of consequence.

$7.50 means its gone up. I've had a look and my local Woolies now has them for around $8 for a 4 pack. It used to be around $1-1.50 each in packs of 4 or 12, and they had some heavy discounts a while back (https://www.ozbargain.com.au/node/102525).

I have the Campmaster ones posted by icefest above. Also sold at SupercheapAuto or BCF or Masters https://www.masters.com.au/product/9000 ... s-220g-4pk They are also labeled Premium ISObutane as well, and also from AHM originating from Korea (I suspect they might be the same rebranded cartridges as the Festiva branded ones).

I also have some older dark green Gasmate canisters left, and they state 80% Butane 20% Propane on the packaging. These look like this:
.

Reading hikingjim's blog, and the posts here and over at the BPL forums, I take it this 80% Butane 20% Propane mix wouldn't be recommended for cold climate use?

[Moondog55]

On the contrary I think, the higher the propane content the colder the gas mixture will work

[keithy]

On the contrary I think, the higher the propane content the colder the gas mixture will work

It's regular butane though, not isobutane in the Gasmate canisters. From hikinjim's http://adventuresinstoving.blogspot.com ... -cold.html he says the propane burns quicker and you are left with butane.

Close to the bottom of his article he puts in the Not Recommended for Winter use a similar content one from the US:

BRANDS NOT RECOMMENDED* FOR WINTER USE (in no particular order)
- Glowmaster is 20% propane and 80% butane per the side of the canister.
*Because they contain "regular" butane, a very poor fuel in cold weather.

[icefest]

Propane will make it ok for use in a remote stove, but the butane makes screw-on use suffer early flame out.

[Orion]

Any one know what (sea level) boiling point this would result in? I'm guessing -3 or -4 degrees celsius, which means for ski tourers at around 1800 metres, -6 to -8 degrees (due to altitude/air pressure effects). For me, and I imagine for most backcountry skiers, this is very useable, as temperatures below -8 in Australia are generally infrequent, and if I know it's coming I'll cook late afternoon/early evening before it gets that cold; or plan to be in a hut; or use canister warming strategies. They would probably be fine for just about any Blue Mountains winter night as well, I imagine.

If you assume you can ignore the <2% "other" gases it's possible to calculate the boiling point. For a mixture that is one part isobutane and two parts butane with zero propane the sea level boiling point is -5°C (-10° at 1800m). If you add a pinch of propane it improves but only slightly. 1% propane gives you -6°C (-11° at 1800m) and 2% would drop that to -7° (-13° at 1800m).

That would be the theoretical starting value. Actual initial boiling point could be lower due to that "other" category but it would be a relatively short lived advantage. In addition, if you use the gas in the normal upright mode you'll gradually lose the advantage of both the tiny bit of propane and the isobutane as you use up your gas. On top of all this you should consider that gas just above the boiling point may not be enough for adequate stove performance.

I wouldn't try to save a few dollars this way as I have experienced struggling canisters in the cold at elevation. But why not just give it a try and see for yourself?

[Orion]

Moondog, did you ever weigh that bulging canister?



I finally got a gas adapter from G-Works...

[Moondog55]

No as I haven't found my little calibrating weights [ the ones I use for doing speaker measurements] to check the scales.
I could use a 10cent coin I suppose as they are pretty stable mass-wise
I have found a big but empty canister in the shed that has also bulged; it may well have been an overheating problem in storage, although I didn't think it got that hot there

[Orion]

Using coins is actually not that bad. It'll be within 1% unless you use really dirty or damaged coins. I tried it once with twenty US five cent pieces, which each weigh 5.00g fresh from the mint. I took twenty used ones and put them on a freshly calibrated scale. The coins weighed 99.75g, an error of only 0.3%. Of course whatever you measure won't explain how an empty canister bulged.

I've been playing with the Gas Saver. I don't know who told you it was impossible to overfill. I have found it very easy to do.