I use a mid-priced air sprayer.... but I really think an inexpensive airless would do the same job. IT seems to me that once you get a thin even coat on the hull and then tip it out as necessary with a foam brush your in the clear. Brushing the varnish has NEVER worked well for me and I tried everything under hte sun to make it work. The water seperator removes moisture from the airstream before it reaches the air gun. Doug