Torches are useful tools for welding, construction and craft projects, and the success of your project depends not only on the quality of the torch, but also on the type of fuel you employ. Propane and MAPP gas are two of the available fuels for gas-burning tools like torches. The right fuel for your project depends on the exact application of your torch.
Propane gas is a natural byproduct produced during the processing of natural gas or petroleum. It is made up of a three-carbon chain and linking hydrogen to create a highly flammable gas. When propane is mixed with butane, it becomes a liquid fuel used in vehicles for combustion. MAPP gas is made up of a combination of methylacetylene-propadiene and liquefied petroleum gas. When MAPP gas combines with oxygen, it can produce a high-heat flame in projects like welding or soldering.
Both MAPP gas and propane gas are highly flammable and therefore valuable as fuel sources. Both gases are nontoxic, colourless and have the distinctive odour similar to natural gas. The most significant distinction between MAPP gas and propane gas is in their flame temperatures. The flame temperature of propane in oxygen is 2526 degrees Celsius; MAPP gas burns considerably hotter at around 2867 degrees Celsius.
Though propane produces a flame hot enough for small scale welding projects, larger scale brazing, metalling and soldering projects often require a higher-temperature flame. Acetylene was a preferred fuel of choice with a higher burning temperature of 3316 degrees Celsius, but the gas is notoriously unstable and therefore dangerous. MAPP gas provides a flame that is hot enough for brazing and metalling, but the gas is much more stable and safer to use than acetylene. Propane is also widely used as a source of home heating.
MAPP gas is considerably more expensive than propane, so if cost is an issue, propane may be a better choice. MAPP gas is also not a replacement fuel for all welding needs; MAPP gas flames contain high levels of hydrogen that create brittle welds in some large scale metal welding projects, particularly when working with stainless steel. The high-temperature flame is not ideal when working with smaller pipes as the flame may inadvertently damage or melt part of the pipe you intended to protect; unless your pipes are at least 2 inches in diameter, opt for the lower temperature flame provided by propane fuel.