Author: Haroon Khalil
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MISCELLANEOUS SURFACE FINISHES
Apart from the surface finishing materials, the following methods are also used in specific cases: Next Lecture=>
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Types of Distempers
Different forms of distempers are discussed below: 1. White Distempers This type of distemper is prepared by mixing only whitening (i.e., powdered chalk) and glue. 2. Coloured Distempers In this type of distemper, the required colour pigment is added to the whitening before mixing with glue. 3. Oil Bound Distempers A variety of oil paints…
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Constituents of Distempers
Distemper comprises a base, a binder, a thinner and a pigment. Whitening or chalk forms the base, glue forms the binder, water forms the carrier or thinner and a colouring pigment. Distempers are available in a powder form or a paste form. They are to be mixed with hot water before use. This is more…
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Function of Distempers
Distempers are water paints consisting of whitening (i.e., powdered chalk), glue or casein as a binder and suitable colouring pigments. Distempers are used on plastered, cement concrete and on various wallboard surfaces. They are cheap, durable and are pleasing in appearance. They also safeguard the surfaces from adverse weather conditions.
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Types of Varnishes
Based on the solvent used, varnishes may be classified as given below: 1. Oil Varnishes Oil varnishes are prepared from the hardest resin or gums, such as amba, copal, etc., by heating and dissolving them in linseed oil with turpentine. Heat is added to increase the workability. Although it dries slowly, it is the hardest…
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Constituents of Varnish
The three ingredients of a varnish are: resins or resinous substances, solvents and driers. 1. Resins As stated earlier, the commonly used resins are copal, lac or shellac and resin. Copal is available from the earth at places where pine trees existed in the past. It is a hard substance in a variety of forms.…
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Functions of Varnishes
In general, varnish is applied on wooden surfaces of doors, windows, etc. to decorate the surface without hiding the beautiful grains of wood and at the same time to protect the surface from atmospheric effects. Sometimes painted surfaces are also varnished to enhance the appearance of the paint and also to increase the durability of…
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VARNISHES
Varnish is a clear, pale solution of a resinous substance dissolved in either oil, turpentine or alcohol. The resinous substances are amber, common resin, copal, lac or shellac. The solution spread on the surface after drying forms a hard, transparent and glossy film on the varnished surface.