Nitrogen to spray with
Just trying to keep the facts right. Nitrogen is lighter than air and Oxygen. The molecular weight of N2 is 28 air is 29.2 and O2 is around 30. My numbers most like are a little off since I'm using my memory! But the bottom line is they are all very similar. The earths atmosphere is made up of about 80% N2. So adding a tank of N2 to it will have be a very low health risk unless you are working in an air tight compartment. The main advantage of using 100% N2 is O2 can be very reactive with many substances. Get rid of the O2 and you have little chance of corrosion etc.