SECRETS OF PAINT AND STAIN CHEMISTRY

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SHELLAC

Next time you forget to use dormant spray on your fruit trees, and they become infested with those horrid little scale insects that hide under protective wax scales, go out and scrape them all off. Collect the scrapings, mix well in warm denatured alcohol, strain, let settle, and pour off the top layer and you'll have shellac. It takes about a half million bugs to make a quart of shellac ("lac" is a mathematical term meaning "over 100,000"), so you may want to leave the scale-bug-picking to the South. East Asians who raise the loathsome critters, and who must really need the money.

I'm not kidding here, folks. The lac bug makes honey-colored scales that are collected, dissolved in alcohol (or more recently, in acetone), refined, and used as one of the finest furniture finishes ever. Lac is a naturally flexible resin that is refined into a clear polymer that ranges in color from the nearly clear, highest grade (white shellac) to "button lac" that is almost as dark because it comes from the bug. You can buy it ready to use, but the mixed product has a short shelf life. Better is to buy flakes and denatured alcohol and mix your own as you need it.

Shellac/solvent ratios are called "poundcuts," indicating the number of pounds of shellac flakes that are dissolved in a gallon of solvent. The lower the cut, the lighter the shade and thinner the coat.

The basic premix for sale is a "3-pound cut." If you make your own, start with a "2-pound cut": 1/4-pound well-crushed flakes to a pint of alcohol, mixed in a quart glass jar so you can see it. Stir frequently over several hours till dissolved. You can warm it on a hot plate or in hot water to speed the process, but avoid open flame; alco hol is flammable. Strain through cheesecloth. If you have the time, let sit for a couple of weeks and pour clear varnish off the milky cloud of wax at the bottom. Otherwise, plan to wipe with pure solvent after each coat dries to remove wax. For the first coat at least, thin to a "1-pound cut," doubling the volume with pure alcohol if starting with a "2-pound cut," tripling if using a bought "3-pound cut."

The more thin coats you apply (buffing and/or dew axing between coats), the finer the end finish will be.

For interior use only, shellac can be sprayed, brushed, or wiped on (see "Applying a Varnish Finish," below). Shellac keeps water vapor out of wood—reducing swelling/ shrinking that causes joint-breaking wood movement. Curiously, it will not resist fluid water. Remember when you were a kid—always getting your wrist swatted for the whitish ring your moist Coke bottle left on your Mom's end tables? Called "blush," such a ring will usually disappear by itself as the shellac dries. If it persists, the blush can be removed with a little wax or at worst, an easy refinish.

However, alcohol will dissolve shellac even after it is dry. If you were lacing your Coke with Jim Beam filched from the old man's hooch locker, and spilled some on the shellac, the bare wood would have betrayed you to a woodworking elder, and you'd have gotten more than your wrist swatted. Or, that's what happened to me.

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