QUESTION: I inherited a couple of end tables and a coffee table that had some scratches on the tops. I refinished them with a couple of coats of varnish, and they looked very good. But after a while the varnish is flaking. What went wrong, and can I fix it?

<B>ANSWER: </B> What went wrong is that you did not prepare the old finish properly. It must be sanded lightly but thoroughly to roughen the finish and reduce gloss, if any. This will give the old finish a bit of a "tooth" to hold the new finish. That is what you have to do. Make sure each of the new coats is thin - not thinned varnish but a thin layer. It is important to use the proper varnish. It is safest to use an oil-based polyurethane varnish on an old finish; the new water-based polyurethanes may not be compatible with old oil-based finishes. And, if the old finish is shellac, new shellac must be used because both water- and oil-based polyurethanes are incompatible with shellac.

Handyman on Call Peter Hotton is available 1 to 6 p.m. Tuesdays to answer questions on house repair. Call in your questions to 617-929-2930. Hotton also chats online about house matters from 2 to 3 p.m. Thursdays. To participate, go to boston.com. Hotton's e-mail is photton@globe.com.By The Boston Globe