Paint flows backward toward trigger

P

Panorama Mann

Guest
While I was painting, my DeVilbiss DAGR started making a bubbling sound every time the trigger was depressed. I thought it might be a small clog despite using heavily reduced Com-Art paint, but when I put my ear to the cup I realized the bubbling sound was coming from the trigger area. I thought I might have spilled a little paint in there so I twisted up several small pieces of paper towel and soaked up the paint by utilizing the effect of capillary action. Once it was all dried up I started painting again. Within a couple minutes the bubbling sound was back and the trigger area was full of paint again. So I dumped the paint, cleaned the gun and tried again. Same result. Cleaned again. With the trigger, needle and needle chucking guide removed I looked into the rear of the gun toward the front. Everything looked fine but I suspect the needle guide screw somehow became loose. I didn't want to mess with it until I ran the issue past the veterans here in the forum. Any clue about what's happening here?
 
The only thing that holds the paint back from the trigger chamber is the teflon seal in the needle packing nut. Remove it with a long screwdriver, clean it and re-install it. Not too tight. When you feel some tension, stop, insert needle and see how it feels. There should be just the slightest bit of tension grabbing the needle. If too much, release the nut a bit. If too little, tighten it. If it is fully tightened and it is still not dragging, replace the seal.
 
As well paint travelling backward to the trigger area, I think you could have a leak from your air valve which is also allowing air into the trigger cavity, I had a look at schematic diagram of your brush and the valve housing would appear to fixed, i.e. part of the brush body, but in the parts list there is a rubber O-ring whose job it is to keep air out of the trigger cavity so all air is guided to your nozzle, this would be part number 9 in this diagram;

dagrexploded.gif

You should maybe check that this isn't damaged:)
 
Thank you guys! I'm going to try both suggestions. *fingers crossed*
----
Got it all apart and back together earlier. Examined every part with a linen tester. Can't wait to run some paint tonight. I'll let you know how it goes. Thanks again for the help!
 
Last edited by a moderator:
As well paint travelling backward to the trigger area, I think you could have a leak from your air valve which is also allowing air into the trigger cavity, I had a look at schematic diagram of your brush and the valve housing would appear to fixed, i.e. part of the brush body, but in the parts list there is a rubber O-ring whose job it is to keep air out of the trigger cavity so all air is guided to your nozzle, this would be part number 9 in this diagram;

View attachment 35540

You should maybe check that this isn't damaged:)

Checked it out and the O-ring was in good shape, so I tightened it all up a bit when I put it back together. Shouldn't be leaking air now. Thanks much!

The only thing that holds the paint back from the trigger chamber is the teflon seal in the needle packing nut. Remove it with a long screwdriver, clean it and re-install it. Not too tight. When you feel some tension, stop, insert needle and see how it feels. There should be just the slightest bit of tension grabbing the needle. If too much, release the nut a bit. If too little, tighten it. If it is fully tightened and it is still not dragging, replace the seal.

I did this too and the first time I failed to tighten enough because after a few minutes the trigger area was taking a bath. Tightened just a bit more and life is good! Much thanks!
 
Back
Top