When atomized coating particle size is small like a fine mist, the coating will likely level out and dry to a smooth finish. The two spray gun adjustments are your fluid flow rate, and atomizing air pressure to obtain the ideal atomized mist.
The technique to evaluate your atomized pattern is to spray on glass or pre-finished panels. This practice is helpful in adjusting your gun settings for a smooth dry film. The adhesion on glass will likely be poor but that’s not what you are evaluating. Other times we use panels with several previous coats, and we keep sanding them down to a surface as smooth as glass with 320 and 600 grit sandpaper prior to the next test spray-out.
Normally, you cannot expect a smooth HVLP sprayed finish from a coating with a solids’ content of more than 55%, or a coating at +500 centipoises. However, the same high solids and/or high viscosity coating could yield a smooth finish from: conventional, reduced pressure, or air-assist airless spray gun technology.
VIDEO – SPRAY GUN APPLICATION PRESENTED BY SATA