MAPP gas
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225924491
2008-07-16T01:15:29Z
192.88.165.35
[[Image:Compressed gas cylinders.mapp and oxygen.triddle.jpg|250|thumb|A set of MAPP and [[oxygen]] cylinders used for [[oxy-fuel welding and cutting]].]]
'''MAPP gas''' is [[liquefied petroleum gas]] (LPG) mixed with [[methylacetylene]]-[[allene|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 in combination with oxygen for [[welding]] due to its high [[combustion]] [[temperature]] of 2927 °C (5300 °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 brazing/welding gas to be transported at the same given [[weight]]. Also, MAPP is advantageously used in [[underwater welding]], which requires high gas [[pressure]]s (under such pressures acetylene [[chemical reaction|polymerizes]] explosively, 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 [[propane]] fuel due to its higher combustion temperature. A typical MAPP gas brazing operation would involve metals such as aluminum, copper, et al [[Brazing|braze]] (sometimes colloquially and inaccurately called silver solder) steel parts together.
[[Plumbers]] use both MAPP gas and [[propane]] for pipe soldering and brazing, but MAPP gas's higher combustion temperature makes such jobs quicker. MAPP gas is also popular among glass [[lampworking|lampworkers]], for instance [[Glass beadmaking|glass bead makers]].
The biggest disadvantage of MAPP gas is cost; it is between two and four times as expensive as propane (depending on quantity, supplier, and bottle size). While nine kilogram propane cylinders are common, the largest MAPP cylinder available in Australia is three kilograms. Additionally, MAPP gas torches often cost more than propane torches, around 3 times as much.
MAPP is colorless in both liquid and gas form. The gas has a pronounced [[garlic]] or fishy odor at concentrations above 100 [[Parts per million|ppm]] and is [[toxic]] if inhaled at high concentrations.
==External links==
* [http://www.bernzomatic.com/bernzomatic/consumer/jhtml/gasTypeComparisons.jhtml Data on properties of MAPP and similar gasses]
[[Category:Brazing]]
[[pl:Gaz MAPP]]