OK, I purchace a devilbiss starting line spray gun kit, and played around with it a little last night. I don't really understand how to set the pressure.
The gauge at the gun, I read somewhere, should be at 30 psi, which I assume by experimentation, it is 30 psi when the air is flowing. There is a **** on the handle of the gun, that does not affect the gauge reading, but definatly affects the pressure at the tip. If it is turned in (low airflow, with 30psi at the gauge, air flowing), the paint will spray with a good pattern, but large droplets. When turned out (high airflow, with 30psi at the gauge, air flowing), the paint will have more of a mist, but still a good pattern.

Finally the questions! How should I determine the correct setting for the **** at the base of the gun? Am I going about this all wrong, and is there a good online writeup for us beginers to get the settings right?

Thanks for any help!

 

http://www.autorefinishdevilbiss.com/service_bulletins/SB-2-610-A%20(Sta.pdf

Try this link. It looks like Devilbiss calls it an air valve. But, it still has a fan and a flow **** setting. So, in general, try to make sure you air pressure setting is close. Then, back the top **** all the way OUT. That will be the widest fan setting. Then turn the next lower **** all the way IN. Thats the FLOW ****. While you have the gun with paint in the cup, and its pointed at some poster board, pull the trigger easily and with the other hand unscrew the FLOW ****. Keep coming back until there is flow from the nozzle/air cap. As soon as the paint begins to run, you are close. Ease it back in slightly and see how the flow is relative to the side to side travel of the gun. If you close down the fan so it is not so wide, more paint will be coming out of the spray so you will have to ease in the flow as in lessen the amount. It does take experimentation but those settings will get you close. Hope it helps.

 

OOPS, forgot. The spray pattern and flow is based upon holding the gun about 8 inches from the test paper or the target. Generally, any more than that and the paint will shoot dry and any less there will be tons of sag from too close and too much paint.

 

Your sag issue is from the amount of material you're putting down and not so much the air pressure. The trick is to get that happy medium based on your painting speed and style. The devilbiss link dffay gave will give you more insite to how the settings should be but temp, humidity and speed are all factors as well. Play with it a bit and get used to the feel and how it sprays, it'll make you a better painter in the long run.

 

This is a big help. Can't wait to get out and try it again!!
I just couldn't a good link, but the devilbiss link is a good one!
Thanks!!!

 

Heres how I start. I adjust the top ****, the fan all the way out till its widest setting, but turn in till not distorted. The fluid ****, hold you hand on the trigger and turn the bottom **** out till you feel the trigger no longer moving. Then turn it in till you feel the trigger moving in again, and then give another turn or two. Air pressure start at what the y reccommend but you will have to fine tune from there. If you are getting orange peel and large droplets, or going on too heavy and running, you will want to either turn your fluid **** in some or bump up the airpressure a bit, orange peel and large droplets also might mean paint needs to be reduced a touch more and the gun is having trouble atomizing it properly. If its going on too dry and rough, move closer, slow down, or increase fluid or lower air pressure a little. I think I'd leave the **** on the gun completely open, and set my airpressure at my gun regulator with the trigger pulled (the cheapy guages aren't real accurate, with experience kinda know by the sound and knowing your gun. Try use the pressure **** on the gun for fine adjustment.
Keep practicing and spraying, you will make adjustments to your speed, distance, and gun while spraying without really thinking about what you've done. The goal is a good wet coat, as little orange peel as possible, but not to the point of running. Generally use a slower speed activator or reducer you reasonably use in the temps you are shooting. A slower speed will help laying down also, and stay open longer for solvent to exscape. Just leave good flash time between coats, expecially if spraying a dark base that may contain lots of carbon black and hold solvent longer, leave a good amount of time between base and clear.