Paints
Characteristics of an Ideal paint

• Paint is compared on timber, metal, brick and other materials in the form of a liquid which, upon drying, forms a thin film on each painted surface.
• Paint is composed of two main components i.e. pigment also organic binder.
• The pigment is the solid ingredient of the paint and is used in the form of fine powder.
• The organic binder is the liquid part of the paint and it is called a vehicle.
• The vehicle varies with the type of paint.

1. It protects wood from decaying
2. It prevents the corrosion of metal
3. It protects the surface from the harmful effects of atmospheric agencies
4. It gives a decorative and attractive appearance that the surface
5. It makes the surface safe & clean

Characteristics of an ideal paint

1. It should be cheap & economical
2. It should stick well to the surface and should be able to seal the porous substrate.
3. Its consistency should provide easy workability.
4. Each thickness of the paint layer should be adequate during good protection including decoration of the surface.
5. The paint film should dry rapidly.
6. These dried paint films should be ready to withstand the adverse weather effect for a long time without spending shining.
7. It should offer resistance to failure by checking, cracking also flaking separately within thin pieces.
8. It should possess good moisture resistance.
9. Its colour should not fade beyond time.

Constituents about Paint Oil Paint

1. A base
2. An inert filler or extender
3. Colouring pigment
4. A vehicle
5. A solvent or thinner
6. A drier

Base

1. It is generally, metallic oxide and is used in the form of powder.
2. It is a pigment that forms the chief ingredient of paint.
3. The most important purpose of adding a base in paint is to make an opaque(non-transparent) coating to hide the surface to be painted.
4. It provides resistance to abrasion and prevents shrinkage cracks likely to be formed in the film, during drying.
5. White lead, red lead, zinc oxide, iron oxide, and titanium whites are the bases commonly used.

Inert filler or extender

1. It is a cheap pigment added to the paint to reduce its cost.
2. It modifies the weight of the paint and makes it more durable.
3. The commonly used inert fillers or extenders are Barytes (Barium sulfate), lithopone, silica, silicate of magnesia or alumina, whiting, gypsum, charcoal, etc.

Colouring pigments

1. It is a white or coloured pigment, mixed in the paint to get the desired colour of the paint.

Vehicle

1. It is a liquid that acts as a binder for the various pigments, bases, extenders and colouring pigments.
2. The vehicle makes the paint in a state of fluid and helps to spread its ingredients uniformly over the surface to the painted
3. Here forms as elastic, resistant to abrasion including a reasonably impermeable film about drying
4. Refined linseed oil is a commonly used vehicle in oil paints.
5. Tung, perilla, soybean, fish, sunflower, and tobacco seeds are also being used as vehicles in various combinations with linseed oil or without linseed oil

Solvent or thinner

1. That is a liquid that thins the consistency of the paint including evaporation after some paint film has been applied
2. It imparts good properties such as brush ability, smoothness, and flow
3. Turpentine, pure oils, petroleum spirit, and highly solvent Naptha are commonly used as solvent or thinner

Drier

1. It contains metallic compounds and is used in small quantities for accelerating the drying of the paint film.
2. They act as catalysts for the oxidation and polymerization of the vehicle used in the paint.
3. Litharge, lead acetate, manganese dioxide, including cobalt are the driers commonly practised.
4. Not more than 10% (by volume) of the drier should be used in oil paint.
5. If used in excess, they tend to destroy the elasticity of the paint which finally leads to its flaking.

Types of  Paints

The various types of paints

1. Aluminium paints
2. Anti-corrosive paints
3. Asbestos paints
4. Bituminous paints
5. Bronze paints
6. Cellulose paints
7. Casein paints
8. Cement-based paints
9. Enamel paints
10. Oil paints
11. Rubber base paints

Classification of paints

Based on binders

1. Oil paints
2. Paint based on non-oil resins
3. Waterbased paint
4. Miscellaneous paint

Based unused

1. Primer(undercoat & finishing coat)
2. Acid& alkali resistant paints
3. Fire-resistance paints
4. Fungicidalpaints