Paint is a mixture of one or more coloured powders and a liquid. The coloured powder is called a pigment. The liquid is called a vehicle or binder. The vehicle carries the pigment and allows it to spread over the surface. Many vehicles contain a solvent or thinner.
There are basically two types of pigments – prime pigment and inert pigment. Prime pigments give the paint its colour, and inert pigments like calcium carbonate, clay, mica or talc make the paint durable.
Vehicles include oils, varnishes, latex and various types of resins. When a vehicle comes in contact with air, it dries and hardens. This makes the pigment bind with the surface.
There are various types of paints in common use today. The paints often used on walls and roofs are oil-based. Such paints serve to protect wood and metals. Latex paints include wall paints and masonry paints. Many masonry paints are produced with substances like polyvinyl acetate or acrylic emulsions. Lacquers are often used to paint the automobiles. It is made up of a solution of resins in a solvent. The solvent dries up after the laquer is put on. Now we also have fire-retardant paints that protect against any likely damage due to fire. Heat resisting paints are used to cover warm and hot surfaces.
Then there are cement water paints that add colour to cement surfaces, such as a basement floor. In the metallic paints, aluminium or bronze powder is used as an ingredient. Enamel paints contain small amounts of prime pigments. They are often used in bathrooms and kitchens.
Paint is manufactured in the following process in the paint factories. A small amount of the vehicle is put into a large mechanical mixer. Then powdered pigment is slowly added to the vehicle. Thus a heavy paste of these two items is made. Now the paste is put into a grinder to break-up the pigment particles, and scatter them throughout the vehicle. This operation is followed by ‘thinning’ and ‘drying’. Now, the paint is poured until the solution is thin enough for use. Tinting is the next process. A tinter adds a small amount of pigment to give the paint the exact colour and shade desired. The final steps include straining and packaging. The paint is strained through a filter to remove any solid bits, dust or dirt. It is then poured into a filling tank, and finally into metal cans in which it is sold.
