On Dec 2, 2018, at 9:04 PM, tbarney2004 <tbarney@...> wrote:

Nitrogen constitutes about 78% of average atmospheric air, the rest being about 21% oxygen, and 1% other gases and water vapor. As Mark said, bottled, it will be dry, ie humidity content of basically 0%. As such, it should be perfectly acceptable for use as propellant for an air brush. The 20lb cylinder should maintain very consistent pressures as well as it is emptied at normal spraying rates.

Tim Barney

On 12/2/2018 9:48 PM, mark_landgraf via Groups.Io wrote:
Andy

Bottles can be refilled for 10 years before they need to be re-certified. Normally you exchange them at the local welding supplier.

The gas in the tank will have no humidity it. That can be beneficial.

Changing the gauge on a regulator can be problematic. It would probably be easier to add another gauge, of a lower pressure range, downstream, closer to the airbrush.

Mark Landgraf
Albany NY
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On Sat, 12/1/18, Andy Carlson <midcentury@...> wrote:

Subject: [RealSTMFC] using bottled nitrogen for air brush painting
To: "STMFC" <main@realstmfc.groups.io>
Date: Saturday, December 1, 2018, 1:05 PM
I was gifted a full 20 pound
bottle of Nitrogen recently. It was last hydro tested
in 2015. It has the dual gauge type of regulator,
though unlike my CO2 regulators, the low pressure gauge is
for 300 psi. At a minimum, I will need to replace that dial
gauge for a lower pressure one.
My question, is Nitrogen useful
for air brushing? I have nothing but good things to say
about bottled CO2, and I am asking if Nitrogen will work as
well.
Thanks,-Andy CarlsonOjai CA