This professional wants to take on some antique refinishing projects someone is offering her, but she’s wondering if there are ways to figure out what kind of finish is already on any particular piece. So is there a way to tell whether the maker used shellac or lacquer or something else?
Michael Dresdner: Sure. Do a chemical spot test. Take a small piece of cloth (a gun patch works well) and soak it with denatured alcohol. (No, rubbing alcohol won’t work.) Press it onto the finish in some inconspicuous spot. In just a minute or two, it will soften the finish and stick to it if the finish is shellac. To test for lacquer, do the same thing using lacquer thinner. If neither attacks it, the finish is most likely oil-based.