Lightweight canister for lightweight stove

[Jan Rezac]

Recently I received the Roger Caffin stove featured some time ago here on BPL. The universal connector developed by Roger makes it possible to use several types of canisters.

A small (and reversible) modification of the stove makes it compatible also with butane canisters used for refilling lighters. The lightest one I can get contain 50 g of gas and weights 75 g (including a plastic cap). Another nice thing is that it is cheap, about 1.5 USD. Although butane wont work well in cold temperatures, it is acceptable option in many cases, especially when liquid feed can be used (as with this stove).

The stove with a full canister weights 160 g, less than most remote canister stoves without a canister:

These canisters have a rather long plastic nozzle sticking from the valve. This nozzle is cut to about 7 mm to work with the modified stove (left – original, right – shortened).

In the stove, I replaced the slider with pin pushing the valve with one without a pin. There is a notch in one end to allow free escape of the gas from the nozzle. The plastic washer retaining the slider in place was replaced with one with larger (4 mm) hole, which has to be wide enough to accommodate the nozzle. The photo shows the original (left) and replacement (right) parts.

There are two more options how to use these canisters with the stove:

The first one does not work – I have tried to cut the nozzle completely at its base and use the canister without modifying the stove. However, the valve became stuck inside and did not seal when the pin was lifted. I wasted one canister to learn that this is not the way.

A second option does not require making the new parts for the stove. If the pictured parts are removed, the cam valve of the canister connector can trigger the nozzle of the canister directly. To get it working nicely, the nozzle should be shortened a tiny bit to 14 mm. Also, some tubing or tape can be used to make it fill the hole in the stove better to make the action of the cam valve smoother. While this is very easy, I prefer the mod described above, because I do not like the long nozzle on the canister – it would be more difficult to pack it and handle it safely.

[Hikin’ Jim]

Now that is a very interesting idea, Jan. At a certain point, it's no longer the stove that is causing one to carry a lot of weight — it's the fuel and canister.

In the US, there are 100% butane aluminum canisters available (not common, but available) with a female valve similar to the Camping Gaz type non-threaded valve. I wonder if Roger's stove would work without modification with one of those.

HJ
Adventures In Stoving

[Hikin’ Jim]

I'm speaking here of the CV360 canister, available from Coleman in the United States and from Camping Gaz elsewhere.

It looks very similar to the butane canister used in the original post, but the CV360 has a female valve.

Here's another photo. Here, a CV360 canister is shown next to a CV270 canister. A CV270 canister has the standard Camping Gaz non-thread female valve.

HJ
Adventures In Stoving

[Bob Gross]

I think we need to talk about "lightweight" relative to the fuel weight. These lightweight canisters have a full weight and an empty weight, and the difference might be called the fuel weight. Compare the empty weight to the fuel weight, and you get better weight efficiency by larger containers, not smaller ones. So, these small ones only make limited sense if you intend to use one container or less on a given trip.

Besides, ordinary butane (not blended) is bad for freezing temperatures or colder.

–B.G.–

[Colin Krusor]

I agree with Bob that the larger canisters, which are also often more squat in shape, probably have a higher fuel weight to canister weight ratio, but not by a very significant amount, I'd guess (because higher hoop stress requires thicker material for a larger canister).

I take mostly weekend trips, so, if I used a canister stove and a bigger canister, I would often be carrying a partially full canister with more fuel than I need for the trip. A small canister would provide plenty of fuel, and it would reduce total stove weight.

[Bob Gross]

"A small canister would provide plenty of fuel, and it would reduce total stove weight."

A small handful of Esbit tablets might go even lighter, with virtually no fuel container weight.

–B.G.–

[James Klein]

Bob the canister in Jan's post is 50g fuel and weighs 75g total. Only .33% of the weight is in the container. I doubt if any of the standard canisters come in at that effeciciency.

Ronson makes an all isobutane canister but I don't know the breakdown of weights.

[James Klein]

Now Jim I am very dissapointed in you….I assumed you'd have ponyed up for the roger caffin special at first offer.

[Hikin’ Jim]

Yes, but CV360 canisters are aluminum. In temperatures where butane would work well (generally above 40F/5C for inverted operation), they'd be a nice option, particularly for a weekend hike where 50g of fuel would be plenty. Obviously, on extended hikes, the small container size works against you.

You could go even colder if you employed some method of warming the canister.

HJ
Adventures in Stoving

[Bob Gross]

"Robson makes an all isobutane canister but I don't know the breakdown of weights."

In North America, it is probably Ronson.

I've used those before, but I was not impressed by the reliability of the valve.

–B.G.–

[Hikin’ Jim]

> Now Jim I am very dissapointed in you….I assumed you'd have ponyed up for the roger caffin special at first offer.

Unfortunately not. I was unemployed at the time. Of course I'm working now… (but how to hide yet another stove from my wife?)

HJ
Adventures in Stoving

[James Klein]

Jan, I have been a click away from purchasing the caffin stove probably 5 different times. The last time I backed out I told myself "if only it could take those cheap lighter refil cartridges…."

Thank you for tinkering you way to a solution, I don't imagine I'll be able to resist much longer. Maybe roger will sell out soon (A savings account can dream :))

[James Klein]

Yes I meant ronson but the phone autocorrects to Robson and I was lazy proofing the post :(.

Curious, what did you use the ronson cartridge for? And what about the valve was unimpressive.

[Bob Gross]

I had a pocket-size butane torch that could be recharged from a Ronson cartridge. I used about 5% of the cartridge and then left it for several days. When I returned to recharge again, the cartridge was empty. So, on a sample of one, I was not impressed.

In contrast, when I use a Snow Peak butane blend cannister, I get a bad one less than 1% of the time.

–B.G.–

[Roger Caffin]

I have not tested the CV360 canister, but I am 99% sure it would work, at least in principle.
What I do not know at this stage is whether the pin length I am using will operate the CV360 valve. Someone go and test it for me ???

Comment: likely they used the same Lindal valve insert for both.

2nd comment: does anyone in Oz have some empties? I could experiment.

Cheers

[Jan Rezac]

I have looked at the CV360 canister as well. The valve should be the same as in the other threadless campingaz canisters, therefore it should work with the stove without the modifications. It contains 50 g of butane, the same as the lighter refill. If I remember the specs, the CV360 is slightly heavier (90 g full). A major disadvantage is the price, at least here – it is around 9 USD, the same as a ten times larger canister. This rules this option out for me.

To the container to contents ratio: the aluminium lighter refill can is certainly lighter (in relative terms) than other small canisters. One standard threaded canister I have at hand contained 125 g of gas and weights 97 g empty.

[Hikin’ Jim]

The valve housing is definitely a different size. The circumference of the valve is slightly smaller if I recall correctly. Same principal, but a slightly different variation.

HJ
Adventures in Stoving

[Jan Rezac]

For the sake of science, I bought the overpriced CV 360 canister. Here are my findings:

1) CV 360 works well with the unmodified stove. The diameter of the lip of the valve the stove locks into is the same as on other canisters. The central part is slightly narrower than the one on threaded canister.

2) CV 360 is six times more expensive than the lighter refill of the same size.

3) The claimed weight of contents is the same as in the lighter refill canister (52 g). Surprisingly, the CV 360 has somewhat larger diameter so the internal volume should be quite a bit larger. Once I empty the canister, I will know what the actual weights of the butane are.

4) Full CV 360 weights 89 g, the lighter refill weights 73 g. The CV 360 feels more robust. weight of two CV 360s is about the same as a 100 g threaded canister, two lighter refills are lighter.

[Stuart R]

The weight of a canister is influenced by its manufacturing process which is determined by it's shape, as well as it's size. Tall slim canisters, made from a welded tube with two end caps, are much lighter than squat canisters made from a base and a pressed top piece.
For example, this canister (in various "manufacturers" paint colours) weighs 83g when empty, but holds 175g of gas (sorry Jim).

[Hikin’ Jim]

Jan,

Those are interesting results. Thank you for paying a price for science. :)

The CV360 canisters are in my experience the easiest canisters to refill. I use the 230g bayonet connector type 100% butane "long" canisters to do refilling. I can buy the "long" canisters for $1.00 USD. I can refill a CV360 about 4 times from one "long" canister which means I'm paying about $0.25 USD per canister. Not bad. :)

Of course, 52g is fairly limiting for longer or group hikes, but it's perfect for a solo weekend hike. I usually use about 20g/day of fuel when I'm solo.

HJ
Adventures In Stoving

[Jan Rezac]

I have succesfully tried another type canister with the stove. It is the "asian" butane canister. The advantage of this one is that it is really cheap.

I have used the same parts (brass slider without a pin and a plastic washer with larger hole) as in the mod above. The center of the valve is recessed a bit compared to the other canisters and the original ring does not provide sufficient seal. To fix that, I used a different gasket instead of the o-ring (a cylindrical one, 4 mm thick). It was the only reasonable option in the local hardware store. A fatter o-ring (with the same or slightly smaller OD) would be a better option because it would be easier to remove.

[Bob Gross]

Here is a butane canister challege. Try to do this with a butane canister to a Hank Roberts Mini Stove.

–B.G.–

[Dale Wambaugh]

Hey Bob, check this out:

http://www.spiritburner.com/fusion/showtopic.php?fid/399/tid/18563/

[Roger Caffin]

Hi Jan

I would love a photo of the details! Especially all the tech details for the different gasket you used.

Note that the blue butane canister you show in the photo should have an rigid internal intake tube, bending away from the centre to hit the wall. I think it should be aligned with the notch in the rim, so it should be horizontal in your photo. I forget whether it is on the side of the notch or opposite, but if you can point it downwards you will have a liquid feed and the canister should not chill down.

Cheers

[Roger Caffin]

Hi Bob

> Here is a butane canister challege. Try to do this with a butane canister to
> a Hank Roberts Mini Stove.

You mean, something like this?

Picture courtesy Charles A. Hubbard, 04/2011

I think he also had an adapter for Bleuet canister.

Cheers
PS: I think Hikin' Jim may also have photos.

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