Paint gun adjusting.

[jtfx6552]

My take, regulating pressure with a restriction a needle valve, or cheater valve, etc is not a good way to do it. There are too many variables that will cause the pressure drop across that orifice you just set, to change.

A regulator with a spring is the way to go because it can accurately regulate the pressure over a wide range of output flow, and input pressure.

Should it be at the gun or at the wall? Not that critical, although at the gun has some minor advantages, but the trade off is the bulkiness of the regulator on the gun.

At the wall, with a gauge at the gun should work fine as long as you don't kink the hose or step on it. The pressure drop between the wall and the gun isn't likely to vary much, although it could vary a very little bit. Even if you have the regulator at the gun, obviously a restrictive enough kink in the hose will also lower the pressure avail at the gun.

 

[Dean Jenkins]

unless of course I forget to turn it on, and even that's not out of the realm of possibilities!

Lol! My compressor seems to have a connection to my cell phone. As soon as I answer a call and start talking, the compressor kicks on and I have to run over and turn it off.
This happened a few weeks ago just as I was getting ready to shoot some primer.
After I ended the call, started shooting the primer.
All good at first and then less and less paint coming out . . . oh no! Compressor is still turned off . . .
Fun times!

 

[AAE]

For what it's worth, I called SATA today and talked to a tech that's been in all aspects of the biz.
He said to adjust at the wall and leave everything open full at the gun, even with a diaphragm regulator. Change needle size if needed.
But, you have to do what works for you.

 

[shine]

i never owned a regulator until the 90's.

thing to remember. your coming from a 1/2 or 3/4 line choking it down to a 3/8 in the hose for 25ft.

 

[AAE]

The way I see it is that these high end gun manufacturers spend a lot of time and resources to engineer these tools. Who am I to question them?

It's like having a race car and driving it around town. It works, but, you're not using it to it full potential.

 

[Whitesnake]

I’ve heard the DV1 fluctuation before on the digital gauge. It was my understanding where they’re getting the reading from in the gun. Kinda like x amount of pressure at the inlet gives you x amount at the cap kinda deal. Kinda fooling people into thinking they are spraying at low pressures though. I hear that often with the basecoat gun. But if you put a gauge at the inlet you’ll see that’s not the case as shown above. Where as my lph with a rti regulator at the bottom showing 20psi…has a legit 20psi going in. And I’m assuming much less coming out.

 

[Chris_Hamilton]

AFAIK, the only way you can measure at the cap is with a special gauge that replaces the nozzle/needle assembly. Maybe that just with Sata's though.

 

[MikeK]

And I’m assuming much less coming out

I have an Iwata Silver air cap Guage and you lose very little if any iir. Been a looong time ago when this hvlp equipment got started and this same discussion was happening. I was concerned with using the Devilbiss Whirlwind filter on the gun and pressure differential on/off the gun. Which was maybe like 2# if that. Another item I got in the Barry Iwata franchise days.
I'll do it again tomorrow. Got me thinking about it now.