Propane / butane mix is cheaper than propane alone, why would you use one and not the other?
Pure propane has a boiling point of -43 °F (-42 °C), which means that it has a high vapour pressure at common ambient temperatures, and therefore requires a heavy steel canister to safely contain it. So canisters of pure propane are too heavy. Butane is easy to contain because it has a boiling point of 31 °F (-1 °C), but it doesn’t vaporize well when the temperature drops below freezing. Thus, pure butane has major limitations for cool-weather.
The solution is to use a blended fuel consisting of propane, n-butane, and iso-butane. The thinner canisters can handle up to about 30% propane, with the remainder being n-butane and/or iso-butane (boiling point 12 °F/-11 °C). The propane/ iso-butane mix vaporizes well at lower temperatures and provides enough vapour pressure for adequate performance at colder temperatures.
Date published: 2017-01-29