How to Restore Wooden Furniture Finish
Reamalgamation of an Old Finish
Reamalgamation is a grand revival technique that can make alligatored, crazed, cracked, and scratched furniture look like new. Basically, reamalgamation is the near-liquefication of a marred finish so that it dries solid and unblemished. It works like magic, it's easy, and it can eliminate the need for a refinishing job. If it doesn't work, you haven't spent too much time and effort trying.
Alligatoring, crazing, and cracking are all basically the same thing. They're all caused either by sunlight or by temperature changes, and they can all be eliminated by reamalgamation. Alligatored finishes have lots of small lines intersecting into a rough pattern; crazed finishes have erratic lines running everywhere; and cracked finishes have larger lines, or just one line, running across the surface. Scratched finishes can be reamalgamated only if the scratches don't go below the finish. If the scratches are in the wood itself, you'll have to refinish the area.
The type of finish on the furniture determines the solvent used for reamalgamation: shellac is reamalgamated with denatured alcohol, lacquer with lacquer thinner, and a lacquer/shellac mixture with a mixture of three parts alcohol and one part lacquer thinner. Varnish usually can't be reamalgamated.
Before you work on the finish, clean the piece of furniture thoroughly with mineral spirits or turpentine to remove all wax and dirt. Don't work on a very humid day if the finish is shellac; the alcohol used to liquefy shellac can draw moisture out of the air and into the finish, resulting in a haze or blushing.
The secret of reamalgamation is to work fast, especially with lacquer. Start with a small area to get the feel of it; once you're satisfied with your results, go on to reamalgamate the entire finish. Apply a moderate amount of solvent with a brand-new, absolutely clean natural-bristle brush. Purchase a store-bought amalgamator or mix your own. Use denatured alcohol on shellac, lacquer thinner on lacquer, a three-to-one mixture of alcohol and lacquer thinner on a lacquer/shellac mixture.
To reamalgamate the finished surface, apply solvent along the grain of the wood in quick, long strokes; work quickly, and don't let the brush get dry. Don't try to brush out all the cracks or scratches at this point; many of them will disappear as the finish dries. If you work on individual marks too much, you may actually be removing the finish instead of liquefying it.
As the solvent dries, the finish will have a high gloss, and then, after 30 minutes or so, will become very dull. If the reamalgamation was successful, the scratches and nicks will have disappeared, and the finish will look solid.
Reamalgamation is not always a one-step process. If the cracks in the finish are deep, it may take two or three applications of solvent to remove them. If repeated reamalgamation doesn't work, the problem is probably in the wood; you'll have to refinish it.
After the reamalgamated surface has dulled, lightly buff the finish with No. 0000 steel wool, working in one direction along the grain. Don't exert much pressure, just lightly polish the finish. Then wipe the surface clean with a clean cloth. If the reamalgamated finish is very thin, clean the surface with a tack cloth and apply a new coat of the same finish, right over the old one. Let the finish dry, buff it lightly with No. 0000 steel wool, and then wax the piece of furniture with a hard paste wax. Buff the waxed wood with a clean cloth.
Salvaging a Discolored Finish
Blushing, a milky discoloration in the finish, is a common problem with shellac-finished furniture and can also be a problem with lacquered wood. Varnish finishes are not affected by blushing. Blushing is caused by moisture -- prolonged high humidity, exposure to water, or just age. If the haze isn't too deep in the finish, you may be able to remove it with No. 0000 steel wool and oil or by reamalgamating the finish. Deep-set blushing, however, can be eliminated only by refinishing.
When blushing is present in an alligatored or cracked finish, try reamalgamation first; this may remove the blush as well as eliminating the cracks. If the finish is not cracked, or if reamalgamation doesn't remove the blush, use steel wool to remove the discoloration.
Before you start, make sure the surface is clean. Remove wax and dirt with mineral spirits or turpentine. Then dip No. 0000 steel wool in mineral oil, linseed oil, or salad oil, and rub it gently along the grain of the wood. Work slowly, and make sure the steel wool is always well oiled. The abrasive is removing the top part of the finish, leaving a clean finish behind. Dry the wood with a soft cloth and polish it with a hard paste wax. If the blushing is only in the top part of the finish -- and it often is -- this steel-wool rubbing will remove it. Otherwise, you'll have to refinish the wood.
What happens if your furniture finish wears down? We'll discuss how to overcoat a worn finish in the next section.