First off, i'm doing handbrushing, coz i don't have an airbrush. I experienced this with enamel paint, specifically with the touch-up car paints. i already thinned my enamels using solvents (50/50). the first coat was a thin coat, i waited overnight for it to dry, but when i was adding the second coat, the first thin coat smudged and came off with the brush. i know that it came off because of the solvent but how can you prevent the first coat from bleeding? i tried a soft brushstroke approach, but it seems it can't be prevented.