I have a game table that I want to refinish without taking it down to bare wood, but I don’t know whether it has been previously finished with Poly or Lacquer. How can I tell? Does it make any difference in refinishing? If it doesn’t, which would produce the best surface?
Several ways to decide which is currently on the surface. If the table is in it's original finish, probably lacquer as polyurethanes are difficult for a manufacturer to produce quickly.
Another is if you have allowed an iced glass of something to sit and it has left a white ring. That would be lacquer finish.
Yet another, slightly more difficult is to get a small amount of lacquer thinner and rub an area. If the finish softens quickly that would be a lacquer finish.
If you were familiar with sanding each, that would be a way to tell. Problem is, the two act similar when sanded and one needs experience to know which.
Applying a Polyurethane finish over a lacquer finish is not suggested. Poly's are quite finicky and snobbish. They will not hold with any but their own kind. Some manufacturers still produce a "quick dry" oil type varnish which will act as a bonding coat but these are difficult to find.
If the surface is lacquer, check with a local paint dealer to see if he can get you in contact with someone whom will spray the table for you.