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Overview of Torch Cutting

Torch cutting

The tip of your cutting torch is based on the flame characteristics of the fuel gas used, material cutting, and is where all the action takes place.  Your intended use will determine the type of gas you will need as well as the tip used for torch cutting.  Torch cutting tips come in two styles, one piece, and two-piece.

One-piece tips are made from copper alloy and are used with acetylene.  They are machined with either 4 or 6 preheated holes and can handle light, medium, and heavy preheats.  There are different 1-piece torch cutting tips that perform different functions from gouging out metal to cutting sheet metal and other specialty functions.  One-piece tips use methyl acetylene propadiene (MAPP), acetylene, and propylene.  Two-piece tips require cooler and slower burning fuel gases such as natural gas, methane, and propane.

When shopping for tips, finding the right tip for a job can cause major confusion.  The American Welding Society (AWS) issued a Uniform Designation System for Oxy-Fuel Nozzles back in 2000.  In it they asked that all standard tips have the manufactures name stamped on them as well as the identifying fuel symbol, maximum material thickness, and part number for data and reference, however many manufactures still do not follow it due to the extra cost it would entail in the making of the tips.  Make sure, when shopping for tips, you check the oxygen bore size, orifice size, and fuel gas required to run the tip.

There are three forms of gas used in torch cutting, methyl acetylene propadiene (MAPP), liquid hydrocarbon (propane), and acetylene.  When these gases are mixed with oxygen the dangers and risks increase over that torches that use plain air and fuel.  MAPP gas and propane are the lowest temperature burning gases, acetylene is the most commonly used and liquid hydrocarbon takes an entirely different set up then the previous fuel sources, but can be used under water, has a cleaner burn, and uses less oxygen however is more expensive.

When using any oxygen mixed fuel extra precaution needs to be taken.  Oxygen/fuel mixed gases burn much hotter then air/fuel mixes.  One should never use concrete as there base to cut on.  Concrete holds water.  When the cutting torches heat makes contact, the heat will cause the water to expand and the concrete to explode.  Take extra caution and time when cleaning the tips of cutting torches.  Make sure the orifice is always free of any debris and smooth.  Use protective welding gear at all times and welding screens.  Make sure you are using the right size tip for the job and that the tip matches the fuel use.  Always make sure your work area is free of any hazards, things you can trip on, etc and that your hoses are in a position that sparks do not land on them while working.



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