there isn't a specific time, due to the diffrent reducers and catylist which both have a big roll in flash time along with temperature and humidity and air movement which all have alot to do with flash times, so with out giving all of these details i can only recomend the touch test, which is simply just touching a masked off section and waiting until the clear gets past the point of stringing from the sprayed surface and you finger, but not letting it get beyond tacky. if all else failes i believe PPG's tech sheets are avalible online.
