Category: Surface Finishing Materials
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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.
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Types of Paints
Various types of paints are discussed below: 1. Oil Paint The various constituents of an oil paint are discussed in Section 12.2.4. These paints are self-priming and in general do not need any special primer or undercoat. When it is used for general decoration purposes, it is a common practice to apply at least three…
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Constituents of an Oil Paint
Metals and wooden surfaces are generally painted by oil paints. Sometimes walls are also painted by oil paints. Thus, it is worth discussing the constituents of an oil paint. An oil paint is made up of six main constituents, viz., base, inert filler, colouring pigment, vehicle, thinner and drier. 1. Base The base forms the…
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Functions of Paints
Irrespective of the type of paint, in general, the functions of paints are as follows:
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PAINTS
Paint is mainly composed of two ingredients, viz., a base which is a solid material and a liquid called a vehicle. The vehicle carries the solid matter, distributes it evenly and enables the solid matter to adhere to the surface.