When used in the open air, a propane-oxygen torch reaches a maximum temperature of 3,623 degrees Fahrenheit or 1,995 degrees Celsius. Propane is a naturally-occurring hydrocarbon, a component of natural gas or crude oil. In its natural state, propane is colorless and odorless, though a compound is added to create a recognizable smell for detecting leaks. While the gas is often used for heating and cooking, propane-fueled torches are also found in many home workshops, used for thawing pipes or soldering plumbing. In the kitchen a propane torch can be used to caramelize foods.

Propane torches work the best for small soldering or heating jobs because of their portability. While propane-oxygen combinations can reach a maximum temperature of 3,623 degrees F, or 1,995 degrees C, a propane-butane torch only goes up to 2237 degrees F, 1225 degrees C. A torch flame consists of two cones, an outer light blue flame and an inner dark blue flame. The hottest point in the flame can be found at the tip of the inner flame.

MAPP® gas, a mixture of propane and methylacetylene-propadiene, burns at a slightly higher temperature than pure propane. The gas in these yellow cylinders burns at 3,720 degrees F, 2,050 degrees C. Torches designed for high-temperature work combine MAP gas with pure oxygen, which supports complete combustion not possible in ambient air. These torches attain a maximum temperature of 5,200 degrees F and 2,870 degrees C, which is hot enough to melt iron or steel.