Shellac has been used for over 3000years and is considered to be one of if not the best finish for high end acoustic guitars.
French polish on Tasmanian blackwood
Shellac’s acoustic properties and natural beauty are undeniable. Shellac has the ability to bring timber to life with a glass-like transparency and a finish so deep you can get lost in it.
It’s not just the looks and acoustic transparency shellac offers, for the luthier, or French polisher, it is a non-toxic substance. Shellac is harvested from trees found in India and south-east Asia. The substance collected from the trees is produced by the Lac beetle. Feeding on tree sap, the beetle produces a substance known as lac to encase its eggs. When this substance is first harvested, it’s known as stick lac because of the sticks, bugs and other organic matter that it contains. The stick lac is processed by heating and removing contaminants to create the end product in several different forms such as seed lac, shellac flakes, button lac and flac shellac.
From left to right, button lac, flak shellac and shellac flakes
The shellac is then dissolved in alcohol and sometimes de-waxed depending on its intended use. Shellac is available in various colours and can be mixed to enhance natural colours in different timbers.
Shellac is applied by hand with a method known as French polishing. Over many hours, days and even weeks, slowly building the finish with hundreds of microscopic thin coats to produce a finish, which I think is one of the most beautiful available. Although shellac is not as durable as lacquer it is easy to repair and re-finish if required.
I find the process of applying a French polish finish is like a practice in mindfulness. A Zen state if you will, witnessing the timber come to life more with each microscopic coat. No distractions, working in the peace of the early morning or the quiet of an evening is a wonderful experience for me.
French polishing a beautiful Sitka spruce top with Tasmanian blackwood back and sides
Although the traditional shellac finish is not as durable as a lacquered finish, I do also use a hardened shellac product which is shellac with a cross linking hardener. The hardened shellac has all the benefits of a shellac finish with the added bonus of durability close to that of polyurethane. Once fully cured, the hardened shellac finish is water and alcohol resistant.
Australian red cedar with Wenge binding and French polish finish