I just purchased a can of primer and a can of flat white. I used the flat white to paint the entire plane, effectively acting as a primer. I'll try the real primer (advertised as "sandable" on the can) at some point. I used it straight from the can. Since I was painting the entire plane, control wasn't an issue. It went on rather well, not too thick, and it didn't run. Given the fact that only basic colors are available, and that decanting sounds like a pain in the neck, I think I'll just use it for primer. But it was much easier than using (and cleaning!) the airbrush. Also, I use acr