- Telephone:
- 020 8905 0667
- Mon-Fri 9:00AM-6:00PM
- Sat 9:00AM-5:00PM
Shellac is an encrustation surrounding an insect known as Laciffer Lacca, which is a parasite living on certain trees in India and other Eastern countries. The insect is about a 50th of an inch long and has a life cycle of about six months.
The shellac is gathered by cutting the infected twigs from the trees. In this form it is known as Stick Lac. The shellac is scraped off the twigs and washed with water to remove the particles of twigs and other impurities and when dry, is known as Seed Lac. This is put into canvas tubes and heated over a fire. One end of the tube is fixed and the other is rotated to squeeze the molten shellac through the hessian as it melts. The initial shellac that comes through is clean and small amounts are dropped on to a cold stone, where it sets in the form of a thin disc up to about 3" in diameter. This is known as Button Lac from which Button Polish is made. The next amount of shellac that oozes through may contain impurities which would easily be detected visually if the shellac was in the form of a button and it is, therefore, stretched into a thin sheet and crushed, when cold, into flakes, from which French Polish is made. Modern processing plants now exist for producing machine made shellacs, similar to the hand made varieties.
White and Transparent Shellac is made by dissolving the Seed Lac in a hot caustic solution of water and then bleaching the solution with chlorine. After bleaching the caustic is neutralised with an acid, which causes the shellac to precipitate out of solution. In this form it is known as Bleached Shellac. Bleaching shellac alters its chemical properties, so that unless it is dissolved in alcohol within 3-4 days after bleaching, it will become insoluble.
Shellac contains a very small amount of wax from the insect. The wax is insoluble in alcohol and causes the cloudiness which can often be seen settling towards the bottom of the container. Transparent Shellac is made by removing the wax from the bleached shellac by washing it with a petroleum solvent, which dissolves the wax but not the shellac.
