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Ali Hamza
Ali Hamza
Mechanical
20 Jan 2019

How Varnishing is done??

Varnishes:

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.

Application: 

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.

Varnishing:

Varnish is applied as under:

Preparation of surface: The wood work is made smooth by  rubbing it with sand paper and the surface is cleaned. Knotting: It is the process of covering the knots in the wood  work, using any of the following methods. 

Size Knotting: A coat of red lead ground in water mixed with glue is applied. After it dries, another coat of red lead ground in  oil and thinned by boiled turpentine oil is applied. 

Patent Knotting: Two coats of varnish prepared by dissolving shellac in methylated sprit are used. 

Stopping: The surface of the wood work is then rubbed again and cleaned. Before rubbing, the surface is applied with size of  hot, weak glue. 

Varnish Coat: Varnish is then applied in two coats. The second coat is applied after the first has dried.