Paint Gun Help

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gerahead

Glutton for Punishment
Joined
Aug 19, 2009
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Maple Grove, MN
I am having some problems lately with my HVLP gun. It is a Devilbiss Starting Line gun using a 1.3 tip and 20-25 psi inlet pressure, spraying PPG Omni primer. I have used this gun numerous times with no issues and all of a sudden, the last 2 or 3 times I have used it, it has caused me some problems. What is happening is that paint is dripping out of the gun tip after I put the paint in the cup without any pressure on the trigger at all. I have had it in a holder while pouring the paint in and it has run out all over the floor. I have had to screw the flow needle pretty much all the way in until I get near the object to be painted. I believe the gun is clean (I haven't done anything differently from when it worked flawlessly). I cannot find anything that would cause the problem. I religiously clean the gun up immediately after use every time I use it. I have no idea where to start. Anyone have any ideas? Thanks in advance. L8r

Jim
 
Jim, it depends on the paint you used in the past,and what you cleaned it with. If you have a gun that has a rubber gasket inside when you take the nozzle off and have sprayed lacquer or cleaned it with lacquer thinner ,then the little black o ring gasket may be corroded or eat up, if you haven't ,then take it apart and clean all the little holes in the head (i use a single strand out of a small wire cable). Also take the back screw off and watch how the spring comes out and pull the entire inside of the gun that goes thru the trigger all the way to the front tip, i had sprayed clear with mine and used fast hardner, thought i cleaned it fast enough ,but the clear had hardened spraying my truck, then about a month later, tried to spray base coat on car and it came out in big drops. Forgot to, if you take the cup off, there is a screen and o ring there also
 
Mine (el cheapo harbor freight) will do that if my needle is too far out of adjustment.
 
dart freak, i have 2 or 3 of harbor freights, and they leaked from the time they were new, i wrap a rag around them and spray the underside,or the trunk inside, when they finally get real bad, i use them to spray POR and then in the trash....lol..makes a man wonder what the Chinese man was drinking or thinking the day he put it together
 
So far mine work pretty good I'm happy with them I bought 3 of them one for primer one for paint and a mini touch up one for hard to reach places and I use it on my kg gunkote/cerakote bc it has a .8 tip. So far so good and for 10 bucks with a coupon I dont mind throwing them away and buying another one.
 
Jim, it depends on the paint you used in the past,and what you cleaned it with. If you have a gun that has a rubber gasket inside when you take the nozzle off and have sprayed lacquer or cleaned it with lacquer thinner ,then the little black o ring gasket may be corroded or eat up, if you haven't ,then take it apart and clean all the little holes in the head (i use a single strand out of a small wire cable). Also take the back screw off and watch how the spring comes out and pull the entire inside of the gun that goes thru the trigger all the way to the front tip, i had sprayed clear with mine and used fast hardner, thought i cleaned it fast enough ,but the clear had hardened spraying my truck, then about a month later, tried to spray base coat on car and it came out in big drops. Forgot to, if you take the cup off, there is a screen and o ring there also

Robert,
Over the course of this project, I have used the same paint. I have cleaned it the same way (using lacquer thinner) taking all of the removable parts out and cleaning them. I have run a brush through every passage I can get one through and used toothpicks and pipe cleaners where I can't. Blown everything out with compressed air and visually checked for crap in all the passages that I can see through. Thanks. L8r

Jim
 
Spraying primer and other "hards" can wear out the needle and fluid tip. The parts are high, for a nice gun like yours...…
FinishLine®

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Jim, thats what i was saying , if you spray lacquer all the time you need a gun without that rubber o ring, lacquer and its thinner dissolve that rubber o rings,i have a friend that makes kitchen cabinets and bathroom vanities, he was the one that taught me if you spray lacquer, you need a gun without those rubber o rings, i told him he was full of crap. he had a gun for urethane and one for lacquer, he took them apart and laid them on the table, and the one he used for lacquer didn't have rubber o rings anywhere in it, they looked like brass, and he said its according to which type paint you use to which gun he used, and he said he uses acetone to clean the urethane gun, and lacquer thinner for the other., my gun that was leaking had a small rubber o ring in the front and one on the paint cup, went to a local hardware and got replacement rings for about a dollar for both and i replace them if i happen to spray lacquer
 
Just so I'm understanding this correctly, lacquer thinner will eat rubber o rings, but acetone won't? I hope I just learned something! I have a new Devilbis Tekna Pro Lite that I don't want to mess up by cleaning it the wrong way. I've used lacquer thinner to clean spray guns as long as I've had one, and never had a problem. I've always had cheapies until I got this Tekna Pro Lite.
 
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