I have to admit that I bugged out after first reading shellac's list of ingredients. You see, shellac isn't your average furniture finish. It's not made in a lab with a toxic concoction of unpronounceable chemicals and it's not harmful to inhale. Shellac is actually as natural as it gets — it's made from the reproductive secretions of an Asian insect!
As foul as it may sound, shellac production is quite fascinating and, dare I say, beautiful. It all begins when the female lac bug exudes a sticky resin onto a tree limb, forming a protective cocoon for its offspring. After the swarms of baby buggies hatch, the residue is harvested in the form of "sticklac," a mixture of resin, twigs and bug bits. The sticklac is sifted and the colorful resin that remains (ranging from light blonde to dark amber) is flattened, dried and broken into flakes. Shellac is widely available pre-mixed in a denatured alcohol but is also sold in this flaky form. The flakes are GRRREAT because you can mix them when you need them. Added to which, due to a process called esterification, those dusty pre-mixed cans at the hardware store may have already expired — mixed shellac has a six-month shelf life before it's drying time greatly increases. Think of this expiration date as nature's seal of approval.
Shellac is best "padded on" (read: wiped on) with an absorbent cheese cloth wrapped in a lint-free rag. Since shellac tends to get gummy, it's helpful to sprinkle some mineral spirits (paint thinner) on the surface of your workpiece as a lubricant. Unlike most other finishes, shellac dries quickly allowing the application of several coats in a matter of hours. The famous, and famously hard to achieve, "French Polish" method commonly used by instrument makers involves applying multiple thin coats to achieve a super-glossy, reflective finish. (See first picture)
That said, shellac isn't perfect for every job. Since it dissolves in alcohol, you'd better avoid applying it on a dining or coffee table where a glass of cognac (or a can of PBR) might spill. Booze resistance aside, shellac is one fine finish — it brings out the best in wood grain, is simple to refinish if damaged, and, if you're deranged like me, you'll find its sweet insectival smell strangely appealing.
Now for a bit of history: In ancient times, before synthetic alternatives were invented, shellac was valued as a textile dye. According to the Zinsser Co., a leading manufacturer of pre-mixed shellac, the bug resin was used by the Ancient Indians to decorate leather and silk as well as their own skin. As trade routes between the East and West expanded in the 15th and 16th centuries, shellac's popularity escalated. European painters eventually began applying it as a protective coat on their baroque masterpieces. Factories dedicated to processing and bleaching the dried flakes popped up throughout the continent. Woodworkers soon caught the bug too — until the invention of lacquer and polyurethane in the 20th century, shellac was the world's most popular furniture finish.
Today, shellac still sells well, albeit to a different clientele. Pharmaceutical companies are the industry's biggest buyers, using the edible finish to coat time-release tablets. If you haven't consumed shellac in pill form, you're sure to have had it on a sweet treat. Candy makers also use shellac as a glossy glaze on such snacks as Skittles and Reese's Pieces. So remember kids, when you taste the rainbow, you're really tasting bug secretion!
Johnny is currently blogging his experience as a student and amateur woodworker. You can keep track of his projects on his blog, Woodlearner.