Introduction
There are several different sorts of gas canisters on the market: in the traditional walking/camping area, we have screw-thread, Campingaz, and Powermax (discontinued). In the hardware store or BBQ area, we have cheap spray-pack cans, which hold about the same amount of fuel (220 g) as a mid-sized screw-thread canister (230 g). And we also have various refill cans used for refilling cigarette lighters and so on; they usually come with a whole range of little plastic adapters in the cap. Most of the camping style canisters are expensive: close to $8 for a 230 g of butane/propane, at least here in Australia. But I can buy four of the spray cans, each holding 220 g (~400 mL) of “butane” for just $8 total at the local hardware store. That is so much cheaper!
The “butane” in these spray cans is unspecified, but it is most likely a mix of n-butane (boiling point ~32 F / 0 C) and iso-butane (boiling point 11 F / -12 C), possibly roughly in equal parts. It is doubtful whether the vendors even know what is in the cans with any accuracy. To be sure, that is not good enough for winter use in the snow, but indeed it is usable in 3-season conditions with the ambient temperature above 40 F / 5 C?
Granted, propane bought in any decent-sized container (say 5 kg and up) is even cheaper than the ~$8/kg for the butane in these cans, but just maybe the further cost savings are not nearly as significant. Added to this is the worry about putting straight propane in a canister rated only for a 30%/70% mix: if it gets warm, the canister might be approaching its burst pressure. You just don’t know in advance, and if it goes bang, then it is too late.
These butane cans have a special fitting designed for little table-top stoves, sometimes called “wok stoves”. Unfortunately, the fitting is not directly compatible with our little canister stoves.
The rim around the outside of the Lindal valve and the notch in the rim is extra to what we find with our ordinary fuel canisters, but they do not get in the way. However, the metal tube up the middle above the nipple is “impossible”.
I have seen many cans advertise a thing called Rim Vent Release (RVR), which is supposed to be a safety feature. As far as I can see, the top rim has sets of three tiny slits around the rim. They are the dark marks on the rim in the left-hand photo. After examining them closely, I think these were added after the cans had been made, in a sort of retro-fit. Anyhow, if the internal pressure gets too high, first the top rim deforms, exposing lots of little leaks at those sets of slits, as shown at the left, then the overpressure is released through those leaks, as shown at the right.
You are most likely to have this problem only when running a stove with an exposed flame. So now you have a huge leak of butane next to a flame. The label on one package says  “if activation occurs a controlled fire may start”.
 “Controlled,” eh? Would you prefer a large ball of flame from the vents or an explosion? Hummmm: frankly, I would prefer neither.
Information on the web implies that there may also be a thermally-activated Temperature Sensing shut-off Valve (TSV) inside some butane cans, which also provides some safety. I know nothing about this, and I don’t think it is globally available. It seems to me that it could lead to an explosion.
The bottom line here seems to be that no matter what you do to make something safe, there will always be a bigger fool. Be warned and take care.
Just because the standard fitting on one of these butane cans is incompatible with our stoves is not the end of the story. There are a several adapters on eBay that could allow a butane can to drive a small stove while lying sideways in its “correct” position; one of these is shown here. This correct position is how the can is mounted in a wok stove, and it has the black tab and the fuel delivery tube pointing upwards. In this position, the canister delivers a gas feed.
Member Exclusive
A Premium or Unlimited Membership* is required to view the rest of this article.
* A Basic Membership is required to view Member Q&A events
Discussion
Become a member to post in the forums.
And you get to reuse those canisters as well rather than throwing them away. Good stuff.
Cheers
Yep. Huge value to me in that aspect. I’ve only purchased a very few traditional IsoButane canisters over the last decade because I treat them carefully; inspect them when empty/almost empty; and refill them as above. Ditto the Coleman green one-pounders (which are refilled from my BBQ 20-pounder, which is in turn bulk refilled at the local U-Haul from their giant tank).
The only real expendables are those tall Butane canisters. But I pierce then when empty, pull the tops off (not too hard); toss the metal parts in the metal recycle bin and the plastic vent pipe in the plastic recycle bin. Hopefully something sane is done with those bits down the line…
That’s pretty cool. Never thought of “mixing my own” using similar percentages of Propane and Butane from cheaper sources.
the problem with mixing butane and propane is that as you use it in cold weather, the propane preferentially evaporates. As you get 1/2 or 3/4 empty canister, it will be mostly butane so not as good at cold temperature.
If you use isobutane, it won’t do this – good at cold temp all the way to empty
Or, just take and extra ounce or two of the butane/propane mixture.
All true.
An exception to the “preferential evap of the Propane” problem would be if you used a liquid-feed (upside-down canister) stove. If I understand the theory correctly, the blended pressurized liquid-state Propane and Butane would remain at the as-mixed proportions until the canister is empty. The canister pressure would feed the consistently-blended liquid into the stove, which would convert the liquid to gas via the heated feed-pipe loop.
Me, I don’t have such a nice stove, so I just take the extra ounce or two of fuel, as Jerry suggests.
The uselessness of pure butane at cooler temps is real. Several times I’ve gone glamping/car camping and tried to cook on my pure butane big-burner/big pan Coleman stove (the kind I’ve seen used tableside in Korean and Vietnamese restaurants) at mid-40s F temps. The flow from the canister quickly chills the canister to close to the butane’s 30+ boiling point, and the stove sputters out. So I shift to my backpacking burner and the blended fuel and things go swimmingly.
Or, if with one particular camping buddy, maybe he will have with him his ancient, heavy burner that screws on top of a propane bottle. That thing could feed us at temperatures that none of us (including Roger Caffin *heh*) would likely ever find ourselves camping in.
yeah, liquid feed inverted canister doesn’t have that problem of propane evaporating preferentially
lots of previous threads about this and other techniques to operate at cold temps
what’s good about upright is the evaporation. Any bits of metal or wax will remain in the canister unnoticed. As opposed to liquid feed where the contaminants can get into the valve.  But then it’s more difficult to operate at cold temps.
As opposed to liquid feed where the contaminants can get into the valve.
They can. I filter the gas when transferring from one canister to another, through a Whatman chem lab filter paper. That works well, except when I don’t bother . . .
Cheers
Become a member to post in the forums.