Wall finishes - Painting, its necessity, process etc.

Painting -

   Paints are the fluid materials which are used as a coating on a wall or other surface to finish it. When we apply paints as a coating for finishing the wall, the process is called Painting.

Necessity of painting - 

• It protects the surface from weathering effects of the atmosphere.
• It prevents decay of wood and corrosion in metal.
• It gives good appearance to the surface.

Characteristics of good paint -

• It should have good consistency with good covering materials in form of powder.
• It should not be toxic and should not harm the user.
• It should be economical.
• It should remain properly to the surface.
• It should give pleasant appearance to the surface.
• It should be fire and moisture resistance.
• It should be retained on the surface for long time.

Ingredients of an oil paint -

1. Base - It is the solid component of the paint exists in form of powder. It forms the bulk of a paint. Various bases are white lead, red lead, zinc oxides, iron oxide, titanium white, Al powder etc.
2. Vehicle or carrier - It is the liquid component. It holds the all ingredients of a paint in form of liquid suspension. It makes the paint possible to spread easily and uniformly on the surface. Some examples of vehicles are linseed oil, poppy oil, and nut oil.
3. Drier - As its name, it is used to dry the surface. After application of paints on the surface, the drier, present in the paint, extracts oxygen from the atmosphere and transfer it to the vehicle. This accelerates the process of drying and hardening. Drier also reduces the elasticity of paint.
4. Coloring pigment - This component is responsible for the colour of the paint. It is added to the base to acquire desired colour. It may be a natural colour, calcined colour, preticipitate or metal powder.
5. Solvent or thinner - Solvents are added to the paint to make it thin so that it can be easily applied on surface. It helps the paints in penetrating through the porous surface of the back ground.

Process of painting on new wood work - The process of painting on new wood work is done in following stages : -

1. Preparation of surface - The wood work, which is to be painted, is made well seasoned, free from moisture, smooth and clean.
2. Knotting - In this step, we seal the knots to save the paint film from resin of knots. It can by done by any of these methods - Paint knotting, lime knotting and ordinary or size knotting.
3. Priming - After knotting, priming is done i,e. first coat is applied on the whole surface of the wooden article. It acts as a foundation for the subsequent coats.
4. Stopping - In this step, wood surface is rubbed by pumice stone or glass paper and then all cracks and nail holes are filled by putty. When putty dries, the surface is again rubbed.
5. Second coating / under coating - It is done over prime coating. Colour of this coating is approximately same as that of the finished surface.
6. Finish coating - When under coated surface is completely dried, Finishing is done with desirable colour. It is done very carefully to get the good appearance.

Thank you.