What is French polish made of?

Welcome,


Have you ever wondered what French polish is made of? 
Well, I have some very interesting reading for you today.


Origins of lac:


Lac, the resin, is excreted by the insect Laciffer Lacoa, from, which shellac is produced.  The insect is a parasite living in certain trees in India and other Eastern countries, and India is the biggest exporter of the world’s lac requirements.  The insect is orange-red and about 1.25mm (1/20in) long, and has a life cycle of about six months.  It covers the twigs and leaves of certain trees with a protective resin.
The Male dies after the fertilization of the Female, and upon death both Male and Female insects are trapped in the resin.  The lac, when gathered (stick lac), contains the dead insects and impurities from the bark of the tree. 

Manufacture of shellac:
The lac is gathered by cutting the infected twigs from the trees and then scraping the lac off the twigs.  Once the lac has been removed from the twigs it is washed with water to remove the particles of twigs and other impurities; and on drying it 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 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 onto cold stone, where it sets in the form of a thin disc up to 75mm (3in) 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.  It is from these flakes that which French polish is made.
White and transparent shellac are 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 neutralized with an acid, which causes the shellac to precipitate out of the 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 three or four 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 that can often be seen settling towards the bottom of the container.  Transparent shellac is made by, removing the wax from bleached shellac and washing it with petroleum solvent, which dissolves the wax but not the shellac.