Nitrogen to Paint?

[Doug Krebs]

So I'm taking my normal morning dump and I'm flipping through the harbor freight catalog. Just browsing and see a couple different water traps for compressors.

I know people go through great lengths to get rid of the moisture in compressed air when they paint. Why not just hook up the gun to a nitrogen or CO2 bottle. I'm going to assume one big bottle would probably be enough to paint a car? Maybe it would cost $20 to rent one a month and have it filled?

Not painting anything any time soon, I was just sitting on the crapper and got to thinking

[Graystroke]

I would think it would add more moisture when it is comming out of there at 1800psi and starts to freeze up. U would have to have some special reg. i wouldn't even know where you would start. a good electric fan drier is $500 and will do the job

[Doug Krebs]

I would think it would add more moisture when it is comming out of there at 1800psi and starts to freeze up. U would have to have some special reg. i wouldn't even know where you would start. a good electric fan drier is $500 and will do the job

Yeah but if just wanted to dick around painting something I don't want to spend $500 on a drier. I also don't think my compressor would be up to the task.

I agree with freezing up. It would probably need one of those hi flow regulators. How would it add moisture to the inside of the line?

[AggieTJ2007]

you would have to build some sort of heat exchanger out of coper tube so you don't freeze the paint

[Graystroke]

kinda what he said when you freeze the paint and then it hits the atmosphere it would suck moisture from the air.

[Doug Krebs]

ahh ok, I see what you're saying now.

Just wondering for those of you that have painted, how dry does the air have to be? Do you need a desicant filter?

I was thinking of building one of those "franzinator" deals by the compressor and running a small desicant filter by the gun.

If you've never heard of a "franzinator", it's basically a vertical 2ft long piece of pipe. The compressed air comes directly from pump into the middle of the pipe with a nozzle that directs the air towards the bottom. The air exits at the top and then is plumbed into the tank. There are all sorts of plans on the internet of these things and different theories about them.

I really just want to dick around in the future painting some small things. Maybe one day a car, but probably not with the compressor I have now.

[DRAGOONRANCH]

Since the co2 or nitrogen would be dry in the tank, then I would think that the gas coming out at 50-100 psi would not gather any moisture. The air compressor gets the moisture straight out of the air it brings in correct. The air coming out of the compressor is not cold enough to condense the moisture in the air correct?

[Doug Krebs]

Yeah, but what they are saying is when the cold/freezing paint hits the warmer atmostphere it's either going to form condensation in the air or when it hits the metal.

[DRAGOONRANCH]

I can see how the gas coming out at 1000+ psi would do it, but not at the pressure you would be painting with. I think it's doable, but getting enough flow may be hard.

[Sharpe]

Even if the gas coming out was only 10-20 PSI it is still colder than ****. Ever aired up tires with a CO2 tank? The regulator and air hose get colder than ****. Something tells me if this was a good idea someone would have done it already.

[DRAGOONRANCH]

nope, never really messed with the co2. what psi are you using coming out of the tank

[DRAGOONRANCH]

I am basing my assumptions on this situations on my use of oxygen tanks.

[Sharpe]

My experience with CO2 is limited to setting up a kegerator and helping air up tires on the trail. As long as pressure is being released I dont think it matter what the PSI is, it will still be hella cold. To weld aluminum with a MIG you need straight CO2 for the gas, which means you have to get a different regulator because an argon regulator will freeze up if you use it with CO2. MIGs use 30-40 PSI. It just the nature of the beast.

[Doug Krebs]

I can find info on it for air brushing, but the site said that only required about 1 cfm of air. I believe a normal paint gun needs roughly 10 cfm to operate well.

[Sharpe]

I've been shopping around for one and most need 10-15 CFM.