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Paints are mixture of pigments and binders generally available in liquid state. Different types of paints and their applications in construction is discussed.
Paints form a solid film when applied on a surface. This film protects the surface from many dangers like corrosion, weathering, chemical attacks etc. Timber or metal structures can extend their life by coating them with paints.
Not only protection paints also provides aesthetic appearances to the surfaces. So, paints play a major role in construction works and projects.
- Classification of Paints and their Applications
Classification of Paints and their Applications
All paints are not suitable for all conditions. For different conditions, different types of paints may be useful.
The different types of paints and their applications in construction are explained below.
Different Types of Paints
Following are the different types of paints:
- Aluminum paints
- Asbestos paints
- Anti-corrosive paints
- Bituminous paints
- Cement based paints
- Synthetic rubber paints
- Silicate paints
- Graphite paints
- Plastic paints
- Casein paints
- Cellulose paints
- Enamel paints
- Emulsion paints
- Bronze paints
- Colloidal paints
- Oil paints
Aluminum paints are made by mixing finely ground aluminum with spirit or oil varnishes. Spirit varnish makes the drying period shorter and oil varnish imparts slow drying facility. So, varnish cane be used according to the requirement.
This type of paint is used for painting wood works, metallic surface etc. The layer of paint is hardened by evaporation of spirit or oil.
Aluminum paint has many advantages such as, it is waterproof, resistance against electricity, corrosion, weathering, it can be visible in dark and provides good appearance.
Asbestos paint is a special purpose paint which is made of fibrous asbestos. It is used for covering leakage in metal roofs, for patch works, for protecting surfaces from acid gases and steam.
Rusting of pouts, flashings, gutters etc. can also be prevented using asbestos paint coating.
Anti-corrosive paints are used to resist corrosion. So, this type of paint is widely used for metal surfaces like pipe, external structures which may allowed to corrosive nature etc.
Linseed oil is generally used as vehicle and along with it a strong drier is used to make anti corrosive paint. It is very cheap and lasts longer.
Bituminous paints are obtained by dissolving tar or asphalt in petroleum or white spirit. They provide black appearance to the surface.
Bituminous paints are used for metal structures in under water conditions, iron pipes carrying water. Bituminous paints have good alkali resistant property.
Cement Based Paints
Cement based paints contains cement as the base material. These paints contain cement, accelerator, pigment and other additives. They are available in powder form. By mixing water to this powder and stirred to the required consistency the paint is obtained.
Cement based paint is water proof and can be applied in internal or external surfaces.
Synthetic Rubber Paints
Synthetic rubber paints are made by dissolving synthetic resins in the suitable solvents. By adding suitable pigments to this mixer, the color can vary.
This type of paint is widely used on cement concrete surfaces like concrete walls etc.
This paint is less affected by rain, sunlight etc. It has good resistant properties against acids, alkalis and moisture conditions. It dries very quickly and maintains uniform color throughout the surface.
Silicate paint is a mixture of silica and resinous substances. Silica gives good adhesion to the paint which will form hard surface after drying. This surface can resist extreme heat with great resistance.
Silicate paints never reacts chemically with the metals. So, this type of paint can be used in hot conditions and for metal structures.
Graphite paint is made of graphite which is in black color. It is used for painting underground structures like mines etc. Iron structures are coated with graphite paints.
Plastic paints contain plastic as the base. Plastic paints dry very quickly, provides better appearance and have high covering power. They are used for coating walls, slabs, decks etc.
Casein is a protein which is available in milk curd, is taken and is mixed with white pigments to get casein paints. It is available in powder form or paste form. Colored pigments can be used to get required color.
Casein paints are used for coating walls, ceilings, wood works etc. But for exterior usage, this paint should be mixed with driers.
Cellulose paints are special type of oil paints. They are made of celluloid sheets, nitrogen-cotton, amyl acetate and photographic films.
In case of normal oil paints, layer is hardened by oxidation but in this case layer is hardened by the evaporation of solvent.
It provides smooth finish and is not affected by smoke, water, acids etc. it is very costly and only used for painting aircrafts, motor cars etc..
The main constituents of enamel paints are metallic oxide, petroleum spirit, oil and resinous matter. Enamel paint dries very slowly but after drying it forms very hard, impervious and smooth layer. This layer cannot be affected by acids, alkalis, gas fumes, water etc.
Different colored enamel paints are available in the market. So, they are widely used for painting doors, windows, stairs, decks etc.
Emulsion paints have good alkali resistant properties. This property can be achieved by using vehicles like polyvinyl lactate, styrene, alkyd resin etc. it dries very quickly and it can be washed with water because of its film forming constituent is emulsified in water instead of solvent.
So, this type of paint can be used for all masonry works especially for stucco plaster brick works which contains free alkali.
Bronze paints are reflective paints which are widely used on radiators. It can be used either for internal or for external metal structures.
General vehicle used in the bronze paints is nitro-cellulose lacquer. Pigments used are aluminum bronze or copper bronze.
Colloidal paints do not contain any type of inert materials. It takes long period to settle due to its colloidal properties. When it is applied on the surface, it settles and penetrates through the body of surface.
Oil paints are nothing but normal paints which usually contains a base and vehicle. General base constituents used for making oil paints are white lead, zinc white, lithopone, red lead and titanium oxide. General vehicles used in oil paints are linseed oil, tug oil etc.
Along with base and vehicle, driers and color pigments are also used. The driers used may be litharge, red lead, zinc sulphate and manganese sulphate etc.
Oil paints are very economic and they can be applied in easy manner. They are generally applied in three coats of varying composition.
So, this type of paints can be applied for walls, doors, windows, metal structures etc. But the main disadvantage with oil paints is that they do not suitable for humid weather conditions.