Shellac And Wax Finish

Antique restoration was a large portion of my woodworking business during the mid 1970’s and early 1980’s, and shellac is an almost indispensable material for this type of work.

The shellac resin actually comes from an insect. These bugs known as “Laccifera Lacca” secrete a resin called “lac” to form a protective coating to envelope the eggs they lay. The “Lacca” bug is found on certain trees throughout India and Thailand and the amber colored resin that they secrete is scraped off the trees and refined to produce shellac.

Shellac is sold as a dry product in the form of flakes, being used more for pharmaceutical and food coatings (due to its organic, non-toxic properties) than as a finish for wood. There is a wide variety of types and colors on the market with different properties. The solvent for shellac is alcohol and once the flakes are dissolved, the mixture has a shelf life, so taking this into consideration I usually purchase shellac as dry flakes and mix up fresh solutions every 6 months or so. There are some pre-mixed shellac products on the market which work fine, just make sure that you check the date on the container and test it on a sample board first to make sure it dries well. “Lac” in its raw form has a certain amount of wax in it that occurs naturally. This wax reduces the finish’s resistance to water so I prefer “dewaxed” shellac. Aging also decreases shellac’s resistance to water which is another good reason to purchase it in dry form and mix up fresh solutions as needed. “Cut” is a term used to describe the amount in pounds of dry shellac flakes that are dissolved in 1 gallon of alcohol. For example, a 2 lb cut has two pounds of shellac flakes mixed with one gallon of alcohol. You can vary the concentration based upon your needs. If I want to seal a surface with some “wash” coats, I’ll spray a one pound cut which would be one pound of shellac flakes mixed with one gallon of alcohol. It is a good idea to invest in a scale (there are food scales available for less than ten dollars) for accurate measuring. A two pound cut works well for padding or brushing, so to mix a small quantity measure 2 ounces of dry shellac flakes and dissolve that in 8 ounces (1/2 pint) of alcohol. It will take a day or two for the shellac to dissolve, after which I pour it through a paint filter into another glass jar, label and date it. To pad it, I make a cloth bob by cutting an inch and a half square of upholsterer’s cotton batting and wrapping it with a piece of fine, lint free cloth.

I like to prepare the surface by scraping and sanding to 320 grit. After removing the dust I’ll wet the pad and wipe on multiple thin coats. I like to pad it on in parallel rows, whereas some finishers prefer a circular motion. Shellac has excellent adhesion properties and dries rapidly. Between coats, I’ll sand lightly with 320 grit. I’ll let the finish dry overnight repeating the process if necessary. Once I’m satisfied with the film thickness (I’m going for a thin uniform coating) I’ll allow it to dry overnight and then lightly sand it with 800 grit paper to level any dust. To finish it off, I’ll rub the surface with 0000 steel wool and then wax it. The result is a very smooth surface with a warm satin glow.