MIG is also much easier to learn and faster to weld. For doing other types of welding, like sheet metal, it can be a matter of personal preference. For an auto body repair shop or a novice welder, a MIG is a good, practical all-around welder. Plasma - The fourth state of matter following solid, liquid, and gas. In plasma cutting, a gas such as Nitrogen is sent under pressure through the torch where it begins to swirl and is forced out a small orifice at which point it passes through an electric arc and the gas is ionized.
Regular air contains enough nitrogen that it is used for most shop size plasma cutters.
It results in a very quick, clean cut and imparts little heat into the base metal. Plasma is one step down from a laser. The amount of time a machine can be used at a particular output. Keep in mind, however, that the actual total time a machine can be used continuously is not determined by a timer, but typically by a thermostat within the machine which will shut it off if the machine is too hot and needs to cool down before it does more work. Factors affecting duty cycle include whether or not the machine has an internal fan and ambient temperature of the work area.