Most HVLP guns have an internal filter in the syphon tube; it can cause grief if materials particularly Timeless is left in the gun for any significant period of time. It will plug up the filter and no amount of cleaning with water based solvents, hot or cold, is going to clear it once it gets setup in there, the only recourse is to disassemble the gun and remove the filter. After that make darn sure you mix well and filter everything that goes into the gun. If a gun with filter gets plugged up, it will act like you were trying to coat a canvas with an air brush, no volume no matter how you adjust the gun and the surface may orange peel as what material you are getting out of the gun is nearly dry before it hits the canvas.
I assume that the clogging is due to the Polymers in the mix and the exposure to air in the syphon tube turning it into water resistant plastic that dependent on exactly what type could be resistant to temps as high as 170 – 190 degrees C.
Having rolled Timeless I’ve had issues as well, pulls ink if you work the surface with the roller any at all, if you roll you have to slop in on so the roller doesn’t drag on the surface too much. This is why I now spray, where it works great. You can lay it down heavy quick and thick, two coats and you are done.
One of the deals with spraying at least in my mind is you don’t need a lot of leveling agents, you aren’t leaving roller marks all over the place and should get a very nice smooth surface if your gun is setup correctly.
