What is varnish??
"Varnish is a solution of resin in either oil of turpentine or alcohol." It dries after applying leaving a hard, transparent and a glossy film of resin over the varnished surface.
Applications of Varnishes :
Varnish is applied to the surface to increase its brilliance and to protect it from the atmospheric action.
It is applied to the un-painted wooden surface with a view to brighten the ornamental appearance of the grains of wood.
Composition of Varnishes:
The ingredients of varnish are: Resins, Solvents and Driers.
Resins: Commonly used resins are copal (resin from number of trees, used to make varnish) mastic, amber gum and lac. Quality of varnish depends much upon the quality of resin used. Copal is considered to be the best, toughest, hardest and is very durable for external work.
Characteristics of a Good Varnish:
1. It should dry quickly.
2. On drying it should form a hard, tough and durable film.
3. It should have good weathering properties, resist abrasion and wear well.
4. It should be able to retain its colour and shine.
5. It should be uniform and pleasant looking on drying.