First let me say thanks for letting me join, a friend from the Slick 60's web site recommended I join and see if you can help me with my question. I am new to paint and in the process of getting set up and I am reaching the point of spraying some primer on my truck. I did a search here and couldn't come up with anything relative, hard to explain in a search and get the right topic I guess as it didn't understand my request.

I have a Quincy 5 hp 60 gallon compressor and Devilbis 3 gun spray system with a primer and painting gun as well as some little gun. In setting it up I put a water oil separator in line and then a pressure regulator. The gun manual says 30 PSI at the gun equals 10 PSI at the cap. Well my question starts here. When I set the regulator up at 30 PSI and open the gun it drops to nothing when I open the gun. So I had a second regulator, came with the gun, so I put it on at the gun, then I turned up the regulator at the compressor to 150 PSI and adjusted the regulator at the gun to 30 PSI and got the same results, open the gun and drain all the air pressure to next to nothing. So I opened the gun and adjusted the regulator at the gun to a steady 30 PSI while it is spraying. When I let off the gun it jumps to 100+ PSI at the gun thus when I open the gun it is spraying at a high PSI for a few seconds until it levels out at 30 PSI. 3/8" hose as recommended.

Is this normal?
Am I set up right?
Will it spray so much primer/paint when I first open the gun it will run all over?
Is it ruining the gun to put 100 + PSI through it for the few seconds at the beginning?

If you need more info on the water/oil separator or other info let me know, I don't have a filter inline beyond the water/oil separator either, do I need one?

Thanks a ton for any and all input, set me straight I want to get it right.

Welcome.

Never set your wall regulator that high. You will get a few milliseconds of very high pressure through the gun which can cause the gun to "kick", or worse damage the gun.

Start with the wall regulator at around 50 or 60 PSI, put a gauge at the gun handle (NOT a regulator at the gun handle - just a gauge). If all you have is the little 'regulator' that came with the gun, use that but understand that it is not really a regulator it is more of a valve that will just cut down the volume of air if turned in too much. This is another reason not to have the wall pressure so high if you are using one of those valves -- it'll need to be turned down to almost a pinhole before you cut that high incoming pressure down to 30 PSI. You'll lose all sorts of volume and create very high velocity air delivery inside the gun.

So if you have that little valve/gauge put it on the gun handle but turn it wide open, so it is acting as just a gauge.

Then, with the gun empty just pull the trigger on the gun, keep it pulled...and turn the wall regulator until your gun is seeing consistent 30 PSI. Remember, keep the trigger pulled all the time you are doing this. You want the gun to have consistent 30PSI all the time the trigger is pulled.

Don't worry if the pressure drifts up a little after you release the trigger, that's normal. It should not drift up to the compressor charge (over 100 PSI), however - if it does then your wall regulator is either also just a cheap valve setup or it has a broken diaphragm.

Here's another similar post I made on this topic awhile ago:

viewtopic.php?p=174276#p174276

Thanks for the quick reply Chris, I appreciate your insight and I will give this a shot tonight after work and see if I can't get this set up right. Can you recommend a good gauge to put on at the gun to replace the "regulator" that I have there now or will any gauge work.

Thanks again.

Cory

That gauge that came with the gun is fine, as long as you don't think about it as a "regulator". Just turn the knob on it wide open and you have yourself a decent gauge for measuring the PSI at the gun handle.

Next level on this would be to make up a short hose whip with the correct couplers on each end and a gauge on a "T" fitting. You can use a cheap air gauge they sell in the tool area of Home Depot if you want.

That way you have a quick/easy way of connecting in the gauge, setting the pressure, removing the gauge then "go". Not many people I know like having extra unnecessary hardware hanging off the bottom of their gun while painting...but like I said for now if you just want to use that gauge that came with the gun you are fine.