Auto Painting Question Need Help!!

[Hookedtrout]

I am reaching the point of spraying some primer on my truck and completely new to painting but determined to do it myself. I did a search here and couldn't come up with anything relative.

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. So I had a second regulator 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 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 140 PSI thus when I open the gun it is spraying at 140 PSI for a few seconds until it levels out at 30 PSI.

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 140 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.

[grump]

Cory, I wouldn't want to run 140 lbs thru your gun too much, it definitely won't do it any good. You have an obstruction some where in your line that's causing the air pressure to bleed off way faster than it can be replaced in the line. Do you have a shut off valve at the compressor? If you don't have one you should put one in and then start from scratch and put your water separator in the line and open the valve and see if you maintain pressure then add your regulator and open the shut off valve again and see if you maintain pressure. One of those should be your problem unless I'm missing something. If you don't have a on and off valve at the compressor put one in. If you ever have a air hose come loose you'll want to be able to shut that air off quick. I hope this helps in some way. Grump

[Hookedtrout]

I do have a valve at the tank so I can shut it off, it maintains the pressure fine if it's set up at full pressure to the regulator at the gun. The only time it bleeds off fast is if I try to set the regulator at the tank to 30 PSI as recommended. Then it bleeds off as soon as I open the gun, i.e. it won't hold the 30 PSI through the air hose. If I turn it up to 140 at the tank it holds 140 to the gun regulator but the regulator at the gun set at 30 PSI with the gun open and spraying jumps to 140 when I shut the gun off? Shouldn't the regulator restrict what gets through to 30 PSI if it's set at 30 PSI while open no matter what? When I first open it there is a bunch of air going through until it comes back down to the 30 PSI that it is set at. In my mind once you set the regulator it shouldn't let one PSI more through no matter what. If I set the tank regulator at 30 PSI I can understand the air hose losing air quick when the gun is open it doesn't have enough pressure coming through to sustain a constant 30 PSI in the hose, maybe my hose is too long or not big enough, it's one of the small diameter light hoses, I have a bigger hose, maybe I should try that for starters, I think it's shorter as well.

Thanks Grump for helping me out, I don't get frustrated I just like to learn and understand and get it right before I put the primer in and make a mess!

[skidoorulz]

Answers to your questions
No
I don't know
Yes
Quite possible
Is your oil and water separator installed in the right direction. Flow direction. Use 3/8 air hose not 1/4. Run an air wrench on 1/4 and then switch to 3/8 and you will see why.

[Hookedtrout]

Answers to your questions<br abp="410">No<br abp="411">I don't know <br abp="412">Yes <br abp="413">Quite possible<br abp="414">Is your oil and water separator installed in the right direction. Flow direction. Use 3/8 air hose not 1/4. Run an air wrench on 1/4 and then switch to 3/8 and you will see why.

Oil and water separator is set up in the right direction, hose could definitely be an issue, I will switch and give that a try thanks for the insight, I'll reply tomorrow and let ya know if this solves it.

[kstones63]

The shorter the air hose, the more even the air pressure. I have several fittings around my garage and use a 15 ft. hose for the paint gun.

Kevin

[slick4x4]

I'm thinking too small a regulator.....

[bruceandersson]

I have a separate regulator and hose off my hard line for painting. Its 1/2" as are all the couplings. Your gun is designed to work on low pressure but high volume of air, so you have to ensure you are getting the high volume. Most airlines and couplings are 3/8" as the volume is not as much of an issue as the pressure. You also could have the air adjustment on the gun open to far. You should run the test with something in the gun to actually spray.

[Hookedtrout]

Thanks for keeping the input coming, I think you guys have given me some great direction, if it weren't for the job that funds all the fun I'd be giving it a try right now. I'll give it a shot tonight and update you all. If it works I'll have more painting questions I'm sure, love this learning something new, if I'm not pushing my limits I'm bored stiff in front of the time wasting tv.

Kevin, thanks for the insight, this is my plan, I don't have several outlets and my shop is too big just kidding no such thing but it would cost me truck money to plumb all the way to the other side. But I do have a shorter, larger diameter hose so that is the plan for now.

Bruce, I did plumb a separate line with the water/oil separator and regulator so I'm set up that way as well. Thanks for the detailed explanation that makes it much more clear. I think my larger air lines are 3/8" but they are larger than the one I was using, I like the small light one as it's easier to drag around but sounds like it won't work for this HVLP, works on my other fence painting gun great but it's not HVLP, no idea what it is but it isn't that. As for the gun, it's set where it came from the factory, I'll put something in it and play with the larger air hose.

Slick4x4, the regulator is the one that came with the spray gun so I assume it should be good to go but I'll keep that in mind if all else fails. Thanks

[Hookedtrout]

Claimed some success in fixing my loose hood on a post over in the truck talk but no such luck on the paint gun air control. I hooked up the larger size, shorter air hose and then tried again to adjust the two regulators and I still get the same results. I have to have the regulator at the tank turned up in 100+ PSI range and then at the gun if I set the regulator to 30 with the gun not spraying it drains right out to nothing and if I set the gun regulator to 30 PSI with it open and spraying it maintains 30 very well but when you shut the gun off it jumps the pressure on the regulator up to 100+ and when you start spraying again it sprays more than 30 PSI for a few seconds.

Not sure if this is normal or odd but it doesn't seem to make much sense to me, I guess I just don't understand regulators like I should, to me if you set a regulator at 30 PSI it should never allow more than 30 PSI through?

If anyone has any other ideas I'm open to suggestions, I ordered a different in line filter seen here. http://goo.gl/soGf6M

[Hookedtrout]

Posted on the Autobody101 site and the advice was given that the regulator at the compressor should be set around 60 PSI and then the regulator at the gun should be wide open or no regulator used just a gauge and then hold the gun open and adjust the compressor regulator to sustain 30 PSI at the gun while open. I haven't tried it yet but will give it a shot tonight, just wanted to share in case it helps someone else out following the information here.

[mitzel]

30psi is with the trigger pulled as suggested in reply
you received from Autobody101. You can adjust
the single regulator at the tank/wall to achieve steady
30psi with trigger pulled, or set the tank/wall at your
normal 60-90psi and use the gun regulator to drop it
to 30psi with trigger pulled. Either way the reading
will spike back upto the full line pressure when you
release the trigger. When you're ready to spray pull
the trigger half way, that'll bleed air without any
material flowing. Should only take ~1second to
stabilize to 30psi, then pull trigger wide open and
you're painting!

[oldtrucks]

Cory.
I have the hlvp set up and I don't have any problems using line pressure at the regulator at the gun. I think you have a faulty pressure regulator at the gun.

[Hookedtrout]

Mike, I think you are on the right track for sure, I'm not sure it's the regulator at the gun or if it's the water/oil separator or what but something is restricting so it forces you to get so high on pressure you can't sustain the 30 PSI. I'm leaning this way because I hooked the DA sander up to this line to see what it would do if I had the regulators wide open, it would only run the DA for a few seconds then it was out of pressure and I had the regulator at the compressor wide open. I have a completely new air dryer system that I'm putting on and I'll start there and see if it makes a difference. If not both regulators are getting replaced with much higher end regulators, these came with the spray gun and the other one which is almost the same thing I bought fairly cheap.

[Hookedtrout]

This is one of the main questions I have had, is it normal so this answer helps me a lot. I didn't know if the fact that the regulator jumped back up to line pressure was normal and having a burst when you start was normal, this sounds like that isn't unusual so I feel better. Thanks!

30psi is with the trigger pulled as suggested in reply
you received from Autobody101. You can adjust
the single regulator at the tank/wall to achieve steady
30psi with trigger pulled, or set the tank/wall at your
normal 60-90psi and use the gun regulator to drop it
to 30psi with trigger pulled. Either way the reading
will spike back upto the full line pressure when you
release the trigger. When you're ready to spray pull
the trigger half way, that'll bleed air without any
material flowing. Should only take ~1second to
stabilize to 30psi, then pull trigger wide open and
you're painting!

[grump]

Cory, when you set the air pressure on your regulator that is what you should get when you pull the trigger on your gun. You should not have to bleed off pressure when you start spraying, Not never not no way.

[slick4x4]

When I paint (defiantly not an expert here)
I run a second smaller air tank after the regulator
It doesn't have to be big ... A 10 gallon air bubble
I have found this setup gives the most steady air supply for me

[Hookedtrout]

Ok a little update, I got the new air dryer installed last night, has a filter then a desiccant dryer. I took out the regulator at that point and the small oil/water separator. I left the regulator at the gun and I set it at 30 PSI open and it does still seem like there is a surge when I first open the gun but not as bad as it was before. If the temps will warm up a bit here I plan to spray some epoxy primer on the truck this weekend so I'll see how that goes and go from there.

[Hookedtrout]

Well, with all the help I finally sprayed for the first time and so far so good. Finished one bed side and put it in epoxy primer.