Is this enamel or lacquer?
Sounds like you are putting too much paint on at once. Too much paint doesn't allow the canned paint to air out, causing bubbles. Try light mist coats with enamel. One light mist coat, let it dry for 15 mins, repeat, repeat, repeat. Testors enamel spray is not the easiest to work with and it takes days to dry. Their one coat lacquer is much easier to use. Takes only one or two medium coats and is dry within a day.
If you were to upgrade to an airbrush, a whole new world awaits you.