Oil based enamels are kind of a finicky group. Never is the viscosity in a new can of paint the same and there is a lot of judgment in getting the right flow. Make sure you get true 100% mineral spirits to thin with, it's clear and flows like water. It took my son, Caleb a while to figure out how to mix his paint. We paint over flocking almost exclusively, the flocking glue is oil based enamel, often rustoleum. I like to keep the airbrush paint compatible with the flocking glue. I thin and filter my airbrush oil based enamel and it's kind of a lot of just eyeballing how thick or thin it is. Kind of as a rule of thumb is how it pours through the filter, if it's too thick, it won't flow through very well. As a general rule if the paint flows through the filter it will flow through the #5. Before I started making decoys I painted with Lifetone Lacquer, it comes in all the colors and is airbrush ready. It's shiny, so it wasn't a good choice for decoys and isn't durable over flocking, more for painting decorative or as in my case painting fish mounts and fish carvings where the glossiness wouldn't matter. I painted with a lot of hydro mist in the 80's when I lived in Kansas and Illinois with all that humidity and it worked fine. When I moved to Idaho where summer humidity is commonly below 20% I couldn't hardly get the water based hydromist to get to the end of the needle before it clogged up. Lacquer based paints are almost self cleaning and until decoys came along it was good for all of my product lines.
The rule of thumb for painting over flocking is to get the viscosity to the point that it will flow through the 1.05, as thick as you can still get it to paint. The stronger the paint the better the coverage and durability. Today it's in the 50's this morning and will top out in the upper 70's, paint is going to flow and plugging will be minimal. Another side note, airbrushing white over flocking requires drying time and for white white like a wigeon cap or wood duck chin straps, they must be hand painted. I have a whole bunch of eclipsed pintails that I'll be enhancing with airbrush white today after sitting a day.
