[Oddjob83]

So I will be getting a Nitrogen tank for our plasma cutter. other than what i recently learned, Nitrogen is better for SS and Air gives better results on Mild Steel, is Nitrogen better for aluminum? and what are the foreseeable problems with having a tank of nitrogen in the shop? is it prone to leaking more like Helium? need a special regulator? or does it use a flow meter? use special fittings that are nitrogen specific?

I am just trying to find out what we may be getting into and what may not be obvious precautions. As far as i can tell, buy tank, add a reg, hook up to plasma cutter, win. but life doesn't always work that way.

[Otto Nobedder]

You can use an Oxygen regulator on that nitrogen tank. It'll flow enough for the gas requirements of a plasma cutter. It should be the same tank-side fitting.

Nitrogen helps reduce oxides in aluminum cuts, especially if you can do a drag cut, where the tip is in contact with the aluminum.

For carbon steel cuts, it helps to keep the tip above the metal, so ambient air is drawn into the cut.

Steve S

[Otto Nobedder]

Also, don't expect much life from each bottle of nitrogen. It's a small version of a compressed air tank, that can hold a lot more air, but it will still be short-lived. When I use nitrogen, I have a 3000 gallon liquid tank to draw from, which is a virtually endless supply.

For mobile work, you should have a compressor for backup. Running out of nitrogen mid-cut is far more irritating than 10 minutes of extra grinding...

Steve S

[Oddjob83]

It is mostly for Stair removal in a factory, just need to cut the stairs out, or gouge the welds. maybe 15 mins of cutting max, if the stairs have to be cut apart to get them out. how much does a full size tank last you when cutting? the 100 lbs 5' tall tanks?

[Otto Nobedder]

If you plan your work carefully, you should get that 15 minutes out of a single bottle, so take two.

The cutter will post-flow to cool the head, and if you're not "right on" the next cut, you're wasting gas.

If you have every step planned out, and keep moving, you may well do this on one bottle. I'm assuming this is rather thin sections, that can be cut rather quickly?

My experience is limited working from compressed N2 bottles, though.

Steve S

[Oddjob83]

3/16 mild steel, with 8" cuts to remove the stairs, 2 sets of stairs to be removed. and then cut them in half to get them out. For this out of shop job i was hoping to use a smaller tank like (i don't know my sizes properly) a 50lb? about 3' tall. I know N2 has a crappy pressure depletion curve, unlike air where you can run it till the needle pins out on 0. N2 would crap out around 1/8 of a tank with a lower compression ratio.

[Otto Nobedder]

Since this is a cut-out, you might be money ahead renting a compressor.

Steve S