Dry spray no flow?
Thread Starter
Racer
Joined: Aug 2005
Posts: 252
Likes: 2
From: lancaster pa
Dry spray no flow?
Hey guy's,can't figure out what's wrong.Iv'e tried spraying 2 times now with my devilbis starting line gun (hvlp)gravity feed.I keep having a problem trying to get enough product to flow out of the gun.When I spray the paint comes out so dry I have to hold the gun 3or4 inches from the panel and pound the paint on to get it to flow.This has happened with ss urethane and yesterday with laquer.The paint in both instances was thinned according to product specs.I have the flow opened up all the way on the gun.30 psi at the gun when trigger is pulled.I kinda think I'm not getting enough volume of air to atomize paint properly? The compressor is more than adequately sized,plenty of cfm's.I'm filtering and removing water w/ a cheap harbor freight filtering system and using the proper size hoses from comp. to filter then to gun.I have a inline regulator at the gun that has a psi gauge on it.The reason I'm thinking it's a air volume problem is I've successfully sprayed before with this gun and another gun I have on my old compressor setup.Should I try test spraying something hooked directly up to the compressor to troubleshoot the problem?
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
Take the fluid cup off and look closely at the pipe leading into the gun body. There's a plastic screen filter in there which can get plugged even if you run a lot of thinner after painting. If that's not the problem I suspect there may be a blockage elsewhere, like in the needle cavity behind the spray nozzle. If you're at all leery of disassembling the thing, seek a body pro in your area who would take it apart and rebuild it for you. Many paint supply stores offer gun reconditioning services.
Racer
Joined: Nov 2006
Posts: 435
Likes: 7
From: Wake Forest NC
Hey guy's,can't figure out what's wrong.Iv'e tried spraying 2 times now with my devilbis starting line gun (hvlp)gravity feed.I keep having a problem trying to get enough product to flow out of the gun.When I spray the paint comes out so dry I have to hold the gun 3or4 inches from the panel and pound the paint on to get it to flow.This has happened with ss urethane and yesterday with laquer.The paint in both instances was thinned according to product specs.I have the flow opened up all the way on the gun.30 psi at the gun when trigger is pulled.I kinda think I'm not getting enough volume of air to atomize paint properly? The compressor is more than adequately sized,plenty of cfm's.I'm filtering and removing water w/ a cheap harbor freight filtering system and using the proper size hoses from comp. to filter then to gun.I have a inline regulator at the gun that has a psi gauge on it.The reason I'm thinking it's a air volume problem is I've successfully sprayed before with this gun and another gun I have on my old compressor setup.Should I try test spraying something hooked directly up to the compressor to troubleshoot the problem?
Racer
Joined: Dec 2010
Posts: 349
Likes: 0
From: Myrtle Beach SC
What is the tip size?
As markids said, it could be there is an obstruction somewhere in the body or passageway of the gun.
Could be the wrong tip size.
Could be you are not reducing the product properly.
As markids said, it could be there is an obstruction somewhere in the body or passageway of the gun.
Could be the wrong tip size.
Could be you are not reducing the product properly.
Thread Starter
Racer
Joined: Aug 2005
Posts: 252
Likes: 2
From: lancaster pa
Thanx for the replies guy's.The tip size is 1.3.I thinned the laquer 1 part paint to 1 part thinner, medium evap.Temp. was about 80 degrees.I tried reduced pressure roughly 25 psi. it appeared to get a little better but the longer I held the trigger in it seamed like I was running out of air.That's what was making me think I'm not getting enough volume of air,the psi. holds pretty steady.
Melting Slicks
Joined: Jun 2009
Posts: 2,709
Likes: 3
From: Savannah GA
If your air pressure stays even but fluid stops flowing it's not an airflow problem... it's fluid. Does the air coming out the nozzle go away as the flow dries up, or just paint volume reduction? At 80 degrees and low humidity, I would personally use a slow thinner, and possibly more than 1 to 1 reduction. If your gun checks out, invest in a hygrometer cup the next time you want to paint... it will remove all the guesswork about how to reduce your material. Your jobber will know which cup matches your topcoat and what "drain times" should be for that cup ... follow their instructon.
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Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
it sounds to me like you need to spray test panels before you put that on your car, it also sounds like youre not getting the paint thin enough, which you would be able to adjust for your humidity and temp. if you were sprayin test panels, do you understand what I'm saying bout "TEST PANELS"
Thread Starter
Racer
Joined: Aug 2005
Posts: 252
Likes: 2
From: lancaster pa
it sounds to me like you need to spray test panels before you put that on your car, it also sounds like youre not getting the paint thin enough, which you would be able to adjust for your humidity and temp. if you were sprayin test panels, do you understand what I'm saying bout "TEST PANELS"
Thread Starter
Racer
Joined: Aug 2005
Posts: 252
Likes: 2
From: lancaster pa
If your air pressure stays even but fluid stops flowing it's not an airflow problem... it's fluid. Does the air coming out the nozzle go away as the flow dries up, or just paint volume reduction? At 80 degrees and low humidity, I would personally use a slow thinner, and possibly more than 1 to 1 reduction. If your gun checks out, invest in a hygrometer cup the next time you want to paint... it will remove all the guesswork about how to reduce your material. Your jobber will know which cup matches your topcoat and what "drain times" should be for that cup ... follow their instructon.
Thread Starter
Racer
Joined: Aug 2005
Posts: 252
Likes: 2
From: lancaster pa
I just checked my cap,there's nothing on the cap.Does that 23psi on the cap mean max. cap pressure or inlet psi ? My owners manual for my guns(It came with a large and small touchup gun)say's 30 psi inlet pressure provides 10 psi at the cap.
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
something I read on a paint forum when I was researching diy car painting was to run the compressor at 50lbs for any hvlp gun and do the gun air adjustment at the gun, that way supply air stayed constant, which is real critical in a hvlp gun. All I know is that it works, and of course.....................
test panels
...sorry , couldnt resist, my bad.
test panels...sorry , couldnt resist, my bad.
That is how I do it 50-60 min at compressor regulator and adjust regulator entering gun as needed for product being sprayed. Right or wrong it seems to work for me. 
going on now.Thanx guy's