Danny
There was a previous set of posts about HVLP guns that you would probably find interesting. It was centered on the Harbor Freight HVLP guns, but they are all pretty much alike.
Here's a copy of some information I provided in an earlier post, but you can search on "HVLP" to get them all:
I purchased both sizes of the HVLP guns from Harbor Freight and have used both of them to prime and paint the interior of my RV8 using epoxy primer and PPG Concept paints. No problems with the plastic cups with either the paints or clean up thinnner.
HVLP is, to me, better than the normal high pressure spray guns, once you figure them out. You will use less paint since there is less over spray, but there are differences in how you use them.
Following are some lessons I learned in using HVLP:
-Make sure you have the pressure going in to the gun set high enough. These guns use 43 PSI going in. This allows the correct pressure at the nozzle, which is about 10 PSI. (You can experiment with different input pressures, but the pressure required for your gun should be stamped or printed on the handle and you can go from there.)
-There are three basic settings on the gun as follows:
-Trigger/needle...hold the trigger completely open (Squeezed in, like a gun) and adjust the needle so that you just begin to feel the trigger move.
-Adjust the fan knob (The knob by the cup inlet) to full open.
-Adjust the cheater valve (Material control) at the bottom of the handle to full open. (Note: If the material is not full open, the gun will "spit" paint and you'll get orange peel.)
The above would be the basic settings for the HVLP gun. If you need to make the fan smaller, you would need to turn down the material some as well to compensate.
Other tips would be to make sure you at least use a disposable filter at the inlet to keep water from the air hose out of the gun.
If you will be turning the gun upside down or tilted, put an old sock over the cup to catch drips from the air hole.
When actually painting, if you are used to a high pressure system, you will need to change technique a little bit. The following should help:
-Hold the gun a little closer to the surface being painted. Remember, with the lower pressure being used, the paint will not spray as far as under higher pressure.
-Move the gun along faster than you would, but not much, since you are closer to the surface. Also, the HVLP will put out more material than you may be used to.
The hardest part for me in painting is patience. Make sure all of your surfaces are properly prepared. Put on a light initial coat (Don't worry about coverage) and let it set up for at least 15 minutes or a little more. (During this time, I pour the unused paint back in the mixed batch and put some reducer in the paint gun. This keeps the paint in the gun from setting up and clogging things up while you wait for the current coat to dry. Put some reducer in the cup, spray some reducer through the gun, then disconnect the air and let the spray gun sit till you are ready to paint some more. A very small amount of reducer is all that is needed for this.) This will allow your subsequent coats to have something to stick to. My second coat is usually a covering coat and then a third (Heavier) cross coat to flow out and make a smooth surface. This has worked well for me, but don't forget to allow enough time between coats for the paint to set up or you will get runs.
Hope this helps. Good luck.