One solution for spraying your project when you don’t have a spray booth or adequate exhaust in you shop is to spray outside. There are some conditions, however, for getting good results.
First, you need to pick a day with temperatures in the high sixties to low eighties. Colder will cause the finish to take much longer to dry and this will create more time for debris and bugs to land on and stick to the finish. Hotter will cause the finish to dry too fast, which may lead to dry spray—the finish drying before it lands on the object. Dry spray results in a sandy look and feel.
Of course, you could slow the drying if you are spraying lacquer by adding a lacquer retarder to the finish.
Second, pick a day with a light breeze. You don’t want wind, but unless there is some breeze, the “bounce-back” finish will settle back onto your work, also causing a sandy look and feel.
Third, spray in the shade but not under a tree. Sunlight will cause the finish to dry too fast, and trees shed leaves and other debris.
Fourth, if you are spraying lacquer, shellac or water-based finish, pick a day that is not too humid. High humidity causes lacquer and shellac to blush (turn milky white) and slows the drying of water-based finish considerably.
This may seem like a lot to take into consideration, but there are always days that meet these conditions throughout most of the year.