Hi all.
Ive recently bought a compressor and Ive been reading the threads and experimenting with different pressures and thinning ratios.
My question is,,when people refer to spraying at say 15 psi,,is that the set pressure before you open the airbrush or while its actually spraying?

Hey Nig,
May want to check out the "Dora 9" thread in the aircraft forum. Crockett said he sets his pressure at 18 to 20lbs. and never touches it. That is with a double action AB such as yours. Sounded a bit high to me but judging from the results of his plane you may want to give it a try.

Hermon

The pressure you use depends on a couple factors...

How thick/thin your paint is and how fine you want to paint. The finer the line you want to paint, the lower the pressure and the thinner the paint. If you want to do a base coat, you can get away with thicker paint if you turn up the pressure.

I set my pressure to approximately 18-20 psi for most of my work.. with the gun spraying (just air while i set the pressure) When I am not spraying the pressure actually will read closer to 25 .. this was a pain in the butt with a single action AB. With the dual action AB I 'spray' just air for a couple of seconds before I pull the trigger back to spray any paint, allowing the pressure to drop to the 18-20 region that I set.

But hey I am new to an AB and everything I learned I picked up here ...

Nigel, I would think that is the working pressure they are refering to.. IF you watch the pressure gauge, it will actually climb a few pounds when you release the trigger of your airbrush.. Once you get the compressor up and running do a test run before adding paint to the cup or bottle.. Set your pressure where you want it, add your paint and have at it...

Dave

One thing to remember is that with a double action AB, the pressure set on the regulator is the MAX pressure you can use. But because you control the amount of air and the amount of paint seperatly with a Dbl action brush you can use from 0 to the regulator setting by just changing how far you push down.

HTH.

Thanks guys.
Thats answered my question.

To look at the same thing from a different angle

The difference in pressure between "not spraying" and "spraying" comes from the resistance of the tube through which the air has to flow between the compressor tank and the airbrush. You should try to keep this as small as possible because with a big difference you are obliged to start with a much higher "in rest" pressure to end up with a working pressure of lets say 15psi.

This means that each time that you open the airbrush yuo will start of with a much to high pressure which can lead to a drop of paint leaving the airbrush when opening it. In most cases not the desired effect.

Make the tube as short as reasonable, as big an internal diameter as possible and avoid bends and cracks.

just my 0.0002 cents