Advice for Spraying Finish Outdoors
I’d like to spray shellac for a finish, but I don’t have an explosion-proof spray booth. Can I do it outside?
Ernie Ruxton, Twin Falls, ID
You can spray shellac or any flammable finish outside, but pick a day with moderate temperature (55° to 75° F) and humidity (under 70%), and find a shaded spot with no direct sunlight. You should avoid strong winds, but some air movement—whether from a light breeze or a box fan—will prevent overspray from landing on the piece.
Even if you do have a suitable environment for spraying, there are a few potential problems to guard against. When sprayed, shellac’s solvent, denatured alcohol, dries so quickly that it can prevent the shellac from “flowing out” correctly. It also can lead to a rough or grainy finish because the shellac partially dries by the time it hits the surface. Avoid both problems by…