The FLASH time is the length of time you must wait between applying layers of your base coat. You must wait for the solvents in the first layer of your base coat to evaporate, so that you can apply a subsequent layer without risking irregularities in the paintwork. Flash times can be affected by temperature and climate, but are usually anything from 5 - 20 minutes. You should always follow the manufacturer’s recommended flash time for your specific automotive paint.