<P> "MAPP gas" is a trademarked name, belonging to The Linde Group, and previously belonging to the Dow Chemical Company, for a fuel gas based on a stabilized mixture of methylacetylene (propyne) and propadiene . The name comes from the original chemical composition, methylacetylene - propadiene propane . "MAPP gas" is also widely used as a generic name for UN 1060 stabilised methylacetylene - propadiene (unstabilised methylacetylene - propadiene is known as MAPD). MAPP gas is widely regarded as a safer and easier - to - use substitute for acetylene . In early 2008, true MAPP gas production ended in North America when production was discontinued at the only remaining plant in North America that still manufactured it . However, many current products labeled "MAPP" are, in fact, MAPP substitutes . These versions are composed almost entirely of propylene with minuscule impurities of propane (<0.5%). </P> <P> Genuine MAPP gas can be used in combination with oxygen for heating, soldering, brazing and even welding due to its high flame temperature of 2925 ° C (5300 ° F) in oxygen . Although acetylene has a higher flame 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 fuel gas to be transported at the same given weight, and it is much safer in use . </P> <P> The MAPP / oxygen flame is not entirely appropriate for welding steel, due to the high concentration of hydrogen in the flame - higher than acetylene, but lower than any of the other petroleum fuel gases . The hydrogen infuses into the molten steel and renders the welds brittle . For small - scale welding with MAPP this is not a serious problem, as the hydrogen escapes readily, and MAPP / oxygen can in practice be used for welding small steel parts . </P>

How hot does a mapp gas torch burn