setup HVLP gun

[DavidF]

I have recently aquired the set of three conversion guns from Vaper and they don't come with any manuals. They have 3 controls; the flow control behind the trigger, the fan control at the top and a third at the bottom where the air comes in that I assume controls the incoming air flow. The gun has a regulator right on the i/p so what do I do with this control? I read somewhere that with HVLP if you have a reg right at the gun then this control is opened fully; is that the case? I have read Flexners book on setting up a gun, but anybody out there got any other info on setting up a gun for spraying WB finish (Target Laquer)?

Thanks.

 

[jeff...]

Dave, I open that valve all the way and control the pressure via an in line regulator / filter combo. I set mine to 30 - 35 lbs which seems to be the best for my setup. You might need to tweak yours though.


Thanks

 

[Gofor]

Dave, the knob at the base of the gun is usually just a restrictor valve (ie needle valve) that cuts the volume of air going into the gun. It should stay full open for most spraying. If you are trying to to a very fine, small spot, you can use it to cut the air flow down momentarily without changing your set pressure. (you'll also have to cut the fluid and adjust the fan pattern for a tight spot) Some people use it instead of a pressure regulator, and it works with practice. The disadvantage is that the pressure builds-up when the trigger is closed, and when you pull it, you get a blast of full pressure which then lowers.
Best to think of it as a "poor man's pressure regulator". It can make the gun functional without using a pressure regulator, but isn't the real McCoy and has some drawbacks. With the set-up you have described, I recommend leaving it full open.

 

[DavidF]

Thanks Jeff and Gofor, just the answer I needed.