Is Nitrogen Gas for Plasma Cutting Stainless Steel necessary?

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I've read quite a few things on the internet about the need for Nitrogen gas (as opposed to compressed, dry air) when plasma cutting stainless steel and aluminum.  Others say, there's enough nitrogen in compressed air to be just fine, as long as it's dry.  Should I go to the expense of getting a nitrogen tank or not?  Up to date, I have only cut mild steel but would like to do a few projects with stainless in the future.  What are your thoughts?
Reply:I think the answer rests in the machine not the material you want to cut.Back in the day I used a plasma machine that was connected to several cylinders of various gas, and the mix of those gases changed with the type ans thickness of the material  All the machines I have used post 1986 have run on shop compressed atmosphere I would contact your machine manufacture.
Reply:You dont need it, but its very beneficial to the quality of the cut to have Nitrogen.Have we all gone mad?
Reply:Compressed air will work just fine as long as long as you're not dealing in super thick materials.CWI, CWE, CST for Miller, Lincoln, Thermadyne, Hypertherm & ESABMillermatic 350PLincoln Invertec 205 AC/DCVictor combo torchESAB PCM 1125
Reply:If you are using a single gas, gas cooled plasma torch...then compressed air is your best bet on stainless. The 20% oygen content (the rest is mostly nitrogen) affects the viscosity of molten metal....producing less dross on stainless. There will be an oxidized (brown/black) edge on stainless when cut with either air , or with nitrogen when cut with a single gas torch. The only advantage for cutting stainless with nitrogen in a single gas torch would be if you submerged the stainless an inch or so under water....the water does not allow oxygen in the surrounding (ambient) air from reacting with the melted edge....and will eliminate the bownish oxidation.With a dual gas plasma torch you can use nitrogen as the plasma gas and either nitrogen or c02 as the shield gas which will improve edge oxidation.With high end high definition class plasma systems (liquid cooled torches) a mixture of 5% hydrogen and 95% nitrogen as the plasma gas and nitrogen as a shield gas is used for a metalurgically pure, weldable edge quality with no oxidation.Thermal Dynamics also has a process with some of their dual gas torches that uses a water mist shield that produces a small amount of hydrogen.....which acts as a reducing gas that virtually eliminates the oxide layer from the edge as well.There are a lot of choices for stainless cutting.....dependent on the type of equipment you have!Jim Colt   Hypertherm