Originally Posted by
Lasse
I see. Thanks for correcting the semantics, I'm no native English speaker.
Regarding butane: doesn't it simply go from gas to liquid state by cooling it to 0°C (273.15 K) at atmospheric pressure (101325 Pa) ? Several sources mention a vapour pressure of 0 Pa in those conditions. Or in other words: it would become liquid again if it's a bit cold outside. To make it at least a bit ontopic: avoid pure butane as a fuel if you plan to cook on cold days.
You are correct. But cooling butane to convert it back to a liquid only works with the pure substance (like the fuel in the tank or canister), not from an air and butane mixture. A few years ago I had an older puncture type Bluet GAZ cartridge on a heater that I wanted to switch from the heater to a stove. That type of cartridge has to stay on the device until it is empty due to lack of shut off valve on the canister. I set these components outside when it was well below freezing (0 degrees C) until they reached the outside temperature, I then switched the canister from the heater to the stove without any problem. Some of those canisters use an isobutane mix, some older ones (like the one I swapped from one device to another) were pure butane. I would not have attempted that with an isobutane mix.
Originally Posted by
robow
Has anyone else had trouble finding iso butane canisters while on the road, and/or do you think they are becoming more commonplace? I noticed that a few Walmarts now carry them but others don't. On several of our more rural rides there were never any camping stores nearby and gas stations rarely carried the stuff although they would often carry Coleman white gas and propane. Because of that I would often take a second canister "just in case" and hated eating up pannier space with it, let alone the weight. The result of those trips is I now have several partially filled canisters around home that I'm not sure I could depend on for a week or two on the road.
On a four day trip a few years ago, I brought all of my partially used canisters, used up all but one of them. I usually weigh my canisters when they are full and assume that they contain the rated amount of fuel, I then mark the bottom with how many grams the canister weighs full. From that I can estimate how much fuel is left by weighing them later. Since it was only a four day trip, I had a lot of extra space so I could carry several extra partially full (or partially empty if you prefer) canisters.
Originally Posted by
cyccommute
"Butane" is short hand for a mixture of gases that are commonly used for backpacking stoves. The real mixture is a mixture of propane, butane and isobutane (which is really 2-methylpropane). I doubt that you can find pure butane for any stove because pure butane has a higher boiling point than the other gases. Once you add the gases together you can push the useful temperature down but not by too much.
If I were to do winter camping...not likely and really not all that germane to the thread...I'd use white gas (also known as naptha) rather than alcohol.
The older Bluet GAZ cartridges (some of which I still own) are pure butane, not a mixture. I believe that they are no longer made in pure butane.
Regarding cold weather camping, in my post number 34 (above) I stated:
"For longer trips or when it will get cold, liquid fuel." and
"I still have several older Gaz cartridges that I want to get rid of, so I expect to use my vintage Bluet stove on some warm weather trips, but I am not buying more of these cartridges."