The way most tabletops are restored when working onsite is by applying more finish. Almost any finish can be used, but there are the following caveats.
• Working onsite makes spraying difficult. It can be done, however, using a turbine HVLP and hanging plastic sheeting to protect everything in the room. Although challenging, spraying has the advantage of producing an almost perfectly flat surface.
• The lacquer thinner in lacquer finishes has the potential of blistering any finish, even old lacquer. Begin by spraying light “mist” coats. Lacquer thinner also has a strong odor, and this has to be taken into account when working in an owner’s home.
• Water-based finish can be sprayed without the risk of blistering and without the strong odors. Many refinishers use this finish, coating over desks at night and on weekends in offices.
• Varnish or polyurethane can be used, but there is a long drying time and strong odor that has to be considered, and the finish should be leveled and rubbed out afterward. To avoid the leveling step, the finish could be thinned at least 25 percent and wiped on, or a gel varnish could be used. Both still dry slowly and collect dust.
• Shellac can be applied successfully over any finish, and the French polishing method of applying shellac is perfectly suited to this type situation. This is the finish and the technique (as shown below) I commonly use when working onsite. PW