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Bugging Out About Shellac

Bugging Out About Shellac
March 21, 2013 Peter Hemerlein

One of the highest forms of finish on fine antique furniture is a French polish done in stages of shellac.  Shellac was used commonly to finish furniture up until the mid 20th century when varnish and lacquer became popular due to their relative ease of use.  The application of shellac is a very labor intensive and time-consuming process where other finishes are more of a “coat and go.”  The effort of properly shellacking an antique or other piece of furniture is definitely worth it, since the result is an absolutely beautiful, rich finish.

Where shellac comes from.

In countries like India, Thailand, Vietnam, China, and even Mexico there are small insects known as Lac bugs which feed on tree sap.  The female insects constantly secrete a substance from their bodies that creates tunnels up and down the trees that they are feeding on.  These tunnels are the raw ingredients to shellac.

The lac bug responsible for making shellac.

The Lac bug. This cute little female insect creates the raw materials for shellac.

The bark of the trees is scraped and the tunnels are processed.  The processing is a simple heating of the lac (term for the tunnels the bugs leave behind) until it liquifies and straining it to remove bark and insect parts and then dried into flakes, bricks, or buttons and sold.

Shellac flakes.

Here are shellac flakes ready for use.

The lac gathered from the lac bugs can come in a variety of shades, from very dark to very light, depending on the type of tree and sap the bugs have been eating.  Pigment can also be added for additional color.

How shellac is used.

The solid form of flakes, buttons, or bricks is dissolved in alcohol and applied using a brush, pad, or even with a sprayer today.  As the mixture is applied the alcohol evaporates leaving only the layer of finish behind.  The beauty behind this is that with subsequent coats, the alcohol actually melts the shellac already on your furniture so when it evaporates you are left with one, thicker coat instead of several thin coats.  This can be done multiple times to build up a thick coat of shellac that is rich and beautiful.

Shellac has several advantages and disadvantages over other finishes such as varnish and lacquer.

  • Shellac can be applied over any other finish.
  • It is easy to repair as re-shellacking the piece actually melts the existing shellac into the new shellac recreating a seamless finish.
  • A shellac finish does scratch more easily than lacquer or varnish.
  • Certain cleaners and polishes will damage or remove shellac finishes.
  • Shellac is not as waterproof as most other finishes.

Besides its application with furniture, shellac is found in several other products that we use or consume everyday. Surprisingly, shellac is edible and is used as a coating on some produce, pharmaceuticals, even candy (think about that the next time you pop some Skittles). Many stains and primers also use it for its odor-blocking properties.