I was using an unnamed HVLP sprayer to finish up a bookcase, and noticed a lot of debris was in the finish. There was one place where I had good light and, looking closely, could actually see debris being deposited WITH the finish! It turns out the air filter under the HVL P was not only very dirty, but was pulling in dirt from the floor. Even after cleaning the filter and sweeping the floor under the unit, it was still depositing junk with the finish.
The filter set up was obviously very cheaply designed. There was no sealing around it and the filter was thin and very porous.
I can see me buying a better HVLP system in the future, and one of the things I will check for is the air intake and filtration.