Mapp gas burns hotter than propane.
MAPP gas is liquefied petroleum gas mixed with
methylacetylene-
propadiene.
MAPP is the
tradename for a product of the
Dow Chemical Company. In Australia it is known as
RazorGas and is a trademark of
ELGAS.
The
gas is used for
welding due to its high
combustion temperature of 2927 °C (5301 °F) in
oxygen. Although
acetylene has a higher welding temperature (3160 °C, 5720 °F), MAPP has the advantage that it requires neither dilution nor special container fillers during transport, allowing a greater
volume of welding gas to be transported at the same given
weight. Also, MAPP is advantageously used in underwater welding, which requires high gas
pressures (under such pressures acetylene
decomposes to explosive
hydrogen and
carbon, making it dangerous to use.)
The gas is also used for
brazing and
soldering, under combustion in ambient air, where it has considerable advantage over competing
liquid petroleum gas (i.e.,
propane-based) fuel due to its higher combustion temperature. A typical MAPP gas brazing operation would involve using it to
silver braze (sometimes colloquially and inaccurately called silver solder) steel parts together.
This gas is popular among glass lampworkers, for instance among glass bead makers.
Its biggest disadvantages are cost, being between two and four times more expensive than LPG (depending on quantity, supplier, and bottle size). While 9 kg LPG cylinder are common, the largest MAPP cylinder in Australia is 3 kg.
MAPP is colorless in both liquid and gas form. The gas has a pronounced
garlic odor at concentrations above 100
ppm and is
toxic if inhaled at high concentrations.
