Spray gun

They work great for small jobs but not small diameter spray pattern.
6" or so. Similar to a rattle can.
Try some experiments but I suspect it will blast too much paint up close.
 
It works pretty well, after a bit of adjustment (I had to re-solder the nozzle tube because it was too low and wouldn't draw any paint). It seems to shoot a heavy coat, though. I haven't used it too much, preferring my regular DeVilbiss gun.