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When using the air brush compressor that is set at 30psi the PSI drops about 10psi on the gauge but remains stable. When I let go of the airbrush trigger it jumps back up to 30psi again. Would you guys consider the 30psi being the setting or 20psi?

Hi mate. If you change the PSI to 30 it will be 30 or close to the whole time you spray. When you hold it down for say 10 seconds. does it lose pressure? or does it stay the same? it should stay the same. I hope this answered your question.

I'm...not exactly sure what question kronicpsycho was answering...but to answer the one you asked ( )

I have the same thing happen with my compressor, I consider the pressure when air is actually being produced the correct one, and adjust psi with the air on, to get it to my desired output.

I might be wrong, tbh until I read your question, I didn't consider any other way, but this seems logical to me.

Am I off mark? the way I understood it was, he sets his pressure to 30 then when he uses it it goes down. Which is normal unless im off mark.. I just woke up

No, he was asking which was the correct pressure, when the air was on, or the higher reading when the air was off.

It might be a symptom of cheaper compressors, but mine also drops by about 5psi when air is being produced, and can't really sustain much above 30 at all.

I go with the reading while the air is on, but yes it does appear to drop once you release the valve that the trigger controls.
This is normal, and to me atleast makes sense.

There is also a drop in pressure when the air travels through the airbrush. It will be different for each one. And is something you can't just go measure.
Suffice to say 30psi at the input valve for the airbrush does not equal 30psi at the nozzle after the air has pushed its way around the airbrush.

The 30psi reading is at the moisture trap attached to the compressors output in most cases. having more or less hose will also make it different again.

Its not a precise number to work from, just a guide line, adjust up/down at your own leisure.

I think they all dip, but compressor goes up to 80psi I think its wonderful. The less psi I set it for the less it dips down. Anyway thanks logically I agree that the correct psi is when pressure is being released I just wanted to make sure I was right.

I am not 100% myself, but with mine I always go with what it dips to, but as you practice you'll actually find a pressure you prefer rather than simply what is recommended, then you'll simply be setting it how you like it rather than how you think others set it. For example I often use a quite low pressure with detail work and I tend to simply try some pressures and see which I like the results of, (I am still learning myself).

Sourced from:http://www.airbrushguru.com/airbrush-dictionary-pressure-drop.html


"Static pressure is the reading before you start the air flowing. Dynamic pressure is the the reading after you start air flowing. Because the dynamic pressure is always lower it's called a pressure drop."

"Pressure drop is more important the bigger your air system is. The more people, stations, and equipment you use off of one system the more important it is to know that you're getting the right amount of air to any one station to do the required job."

This to me says that its the dynamic pressure your interested in - the pressure when air is on.

for what it's worth, the pressure drop isn't unique to compressors. I use a 5 pound CO2 cylinder and get the same behavior on my pressure gauge. like others have posted, I go by what the gauge reads while the air is on. no idea how correct it is, but it's at least consistent

Solar Shock wrote:
I am not 100% myself, but with mine I always go with what it dips to, but as you practice you'll actually find a pressure you prefer rather than simply what is recommended, then you'll simply be setting it how you like it rather than how you think others set it. For example I often use a quite low pressure with detail work and I tend to simply try some pressures and see which I like the results of, (I am still learning myself).

Lower pressure for detail work is vital. To 'pull a hairline' (that is; a line of comparable width to the nozzle) with an airbrush (which they're totally capable of) you need to work at uber low pressure (around 10ish psi) with 'over thinned' paint. And get really really close to the job, so close infact that it becomes a risk that you might stub the needle into the work! It takes really steady hands, especially as most airbrushers would remove the needle guard for this job as it interferes with the airflow when us this close.
With acrylics, this is only really doable with inks, as most acrylics are too thick right off the bat, and loose too much pigment density when you thin them this far.

But the correct working pressure is different for everyone because, the environment is different, different temps, humidity, different paint temp, different paint viscosity, different airbrushes, hose lengths, different compressors, different thinners etc etc... fact is none of us really do this exactly the same as one another, we all pretty much had to play around to find what works best for our own specific situation.
The 30psi guideline, I would say is a bit high, I normally work 20-25psi for basecoats, and 10-15 for details... But again it depends what you want to spray, and on your particular gear. I use Harder & Steenbeck Evolution Silverline 0.2mm for what its worth.

HairySticks wrote:
Lower pressure for detail work is vital. To 'pull a hairline' (that is; a line of comparable width to the nozzle) with an airbrush (which they're totally capable of) you need to work at uber low pressure (around 10ish psi) with 'over thinned' paint. And get really really close to the job, so close infact that it becomes a risk that you might stub the needle into the work! It takes really steady hands, especially as most airbrushers would remove the needle guard for this job as it interferes with the airflow when us this close.
With acrylics, this is only really doable with inks, as most acrylics are too thick right off the bat, and loose too much pigment density when you thin them this far.

You can definitely use normal paint to spray a hairline and if you thin properly, pigment density isn't anything you should worry about. As a matter of fact, writing your name on paper with a hairline spray pattern is awesome practice for learning better control with the airbrush.

When using the air brush compressor that is set at 30psi the PSI drops about 10psi on the gauge but remains stable. When I let go of the airbrush trigger it jumps back up to 30psi again. Would you guys consider the 30psi being the setting or 20psi?

Go with the pressure when you the trigger depressed, it is the most accurate to what you are actually spraying. Just out of curiosity, how long of a hose are you using? Ten pounds of pressure drop seems like an awful lot even for a 1/4" hose.