Polar expedition (or nordic touring) vs Alpine style

If I did more camping below 10F I might be more interested in propane in canister

My last trip it was 23F and windy one day – I was a bit cold.  The next day it was 20F and calm and I was sweating – I had to unzip my jacket and vests.  It’s supposed to get cold a week from now, maybe I can find a place below 20F.  Just using cheap butane.  I do have a canister of isobutane that I found that I could use.  None of this is “polar”.

Propane should NEVER be put into a butane container, regardless of temperature! The vapor pressure is many times higher and will burst the butane container.

You can, however, use propane as fuel for butane stoves by using a propane container that has a Lindal valve, like these. I do it all the time, with BRS3000T, Soto Windmaster, MSR Pocket Rocket, numerous Fire Maple stoves. Propane in a propane canister, not sketchy at all.

Once you get adapters, you can refill the propane container from other propane containers, like those BBQ tanks. Refills for pennies instead of $8-$11 like the canisters.

If you look at graphs of pressure vs temp for butane and propane, propane at 72F is the same as butane at 120F.  My recollection without looking it up again.

But, keeping a canister below 72F is tricky so this probably isn’t a good idea.

Somebody has done this, so it’s more than theoretical

If someone was in real polar Temps maybe it would make sense

I will defer to Hikin’ Jim’s “Adventures in Stoving” blog: “Do NOT fill backpacking type canisters with 100% propane under any circumstances.”

Not saying you’re wrong about the numbers Jerry, just saying it’s very sketchy and consequences of getting it wrong can be catastrophic. I wouldn’t do it myself, FWIW.

another problem with 100% propane is if it warms from the burner when you’re running the stove

I’m not going to be trying this.  I use cheap butane which is 50% nbutane.  Down to 20F.  I have a canister of isobutane that I found but haven’t bothered to use it.

100% propane might be something to try if you’re in polar conditions, below 0F for example