What is Shellac?
Shellac, a remarkable natural product treasured by woodworkers and finishers for centuries, is often lauded for its versatility, ease of application, and splendid aesthetic appeal. Derived from the resinous secretions of the lac insect (Laccifer lacca), shellac originates from the forests of India and Thailand. This tiny insect feasts on the sap of specific host trees and secretes a resin known as lac, which is harvested and processed into what we refer to as shellac. This unique process places shellac in a league of its own, setting it apart from synthetic alternatives like polyurethane and varnish. With a rich history dating back to antiquity, shellac has been utilized in a variety of applications, including painting, as a protective coating for fruits and candies, and of course, in woodworking. The allure of shellac lies in its simplicity and natural appeal, in addition to its reparability and reversible nature.
Shellac Varieties: Types, Colors and When to Use Them
Understanding the different types of shellac is vital to use it effectively. Predominantly, shellac comes in two varieties: waxed and dewaxed.
Waxed shellac, also known as natural or button shellac, contains a small amount of wax naturally present in the raw lac. This type is quite durable and imparts a warm, rich finish to the wood. Waxed shellac is a traditional choice for projects where the authentic, antique-like glow is desired, such as refurbishing vintage furniture or enhancing the grain in aged woodwork.
Dewaxed shellac, on the other hand, has had the wax removed during processing, leading to a finish that is a bit more clear and glossy. Dewaxed shellac is often used when a clear, unclouded finish is necessary or when it will be topped with other finishes. Due to its lack of wax, dewaxed shellac adheres better with other finishes and is, therefore, a preferred choice as a sealer under polyurethane
The color of shellac can vary significantly from pale yellow (super blonde) to deep amber (garnet), depending on the level of refinement and the host trees from which the lac is harvested. Lighter shades, like super blonde, are typically used when you wish to retain the wood's natural color, while darker ones, like garnet, can be used to lend a warm, amber hue to the wood, accentuating its grain.
The Art of Making a Two-Pound Cut
Shown here: how I mix my "two-pound cut" shellac
In woodworking, "cut" refers to the ratio of shellac (in pounds) to alcohol (in gallons). Therefore, a two-pound cut means two pounds of shellac flakes have been dissolved in a gallon of alcohol. The process of making a two-pound cut is simple, yet calls for precision. Begin by selecting a clean, airtight container – glass is often the preferred choice due to its non-reactive nature. Measure out two pounds of shellac flakes and pour them into the container. Following this, pour a gallon of denatured alcohol into the same container. Stir the mixture thoroughly, ensuring that the flakes begin to dissolve in the alcohol. Seal the container tightly and let it sit for a day, periodically shaking it to facilitate dissolution.
After 24 hours, your shellac should be entirely dissolved, yielding a two-pound cut. It's crucial to strain the solution through a fine-mesh filter before using it, to remove any undissolved flakes or impurities that could mar the finish. A two-pound cut shellac is my go-to mix. I might dilute it 50% when first coating raw wood, so it gets absorbed evenly in the grain.