Hi Folks.

I have a few spray guns, I paint guitars mainly but occasionally my car stuf

I have two full size HVLP's and two touchup HVLP's, no problems with these.

I have two full size LVLP guns, and they work great, recently I decided to purchase same brand but a touch up gun 1.2 LVLP. ($400 starr)

Some issues Im havings, have stripped it apart cleaned re-assembled and still the same

As I am spraying, maybe two seconds into the spray I can feel the air pressure pulse and it almost feels like that air pressure is back feeding into the cup, then it sprays good and 2 seconds later a pulse again, putting railway tracks onto the surface.

The material I am painting is nitro, in a HVLP 1.0 nozzle touch up gun, it sprays just fine, but in the LVLP 1.2 bad, between the pulses it comes out nice.

The cup lid is not blocked, I have scrupously cleaned it, what am I possibly missing, is there possibly a missing seal or soemthing not tight enough or a scratch in some area. Does a LVLP gun require a thinner mix, I have not noticed the issue with my full size LVLP guns, but this is my first touch up LVLP.

Steve

Make sure the tip is tight. Some don't seal well just snugged up, you have to tighten them down.