Question Bank of Paint

1. What is paint?

Paint is a liquid surface coating which protect the surface from the weathering action of atmospheric agencies and provide a decorative finish.

2. What are the ingredients or the compositions of paint.

Paint consists of :

• Base
• Vehicle
• Pigments 
• Solvents 
• Driers 
• Adulterants.

3. Write short note of ingredients of paint? 

Base:

• It is the principal constituent of the paint, usually a metallic oxide.
• It makes the paint film opaque and possesses binding properties.

Eg: White lead, Red lead, Zink white, Alumunium powder, Iron Oxide

Vehicle:

• It is also known as binder.
• Vehicle is an oil to which holds the constituents of paint in suspension and helps to spread it over the surface to be painted. 
• It imparts durability, Toughness, water proof ness to the paint film, resistance to weathering, glossy finish to the painted surface and forms the body of the paint.

 Eg: Linseed oil, Nut oil, poppy oil, Tung oil etc.

Pigments: 

• Pigments are finely ground mineral, organic substances of metal powders.
• They are used to hide surface imperfections and to impart the desired colour.
• They protect the paint film by reflecting the destructive ultra-violet light.
• Natural and artificial pigments are available

Natural pigments: 

1. Natural white chalk, 
2. Mastics, 
3. Grey graphite 

Artificial mineral pigments:

1. Titanium dioxide, 
2. Zink white, 
3. Lead white,
4. Chrome oxide, 
5. Red
6. lead

Solvents: 

• They are also known as thinners.
• These are the oils used to dilute the paints and increase the spreading power.

Eg. Spirit,  Neptha, Turpentine oil etc.

Driers: 

• Driers are used for hardening of paints.
• These are chemicals added to paint for specific purposes , as catalysts for the oxidation, Polymerization and condensation of the vehicle in the paint.

Eg. Litharge, Lead acetate, Red lead, Manganese dioxide and cobalt, zinc Sulphate and Lead chromate.

Adulterants: 

• These are substances used to bring down the overall cost , reduce the weight and increase the durability. 
• They are also called inert fillers. 
• The best adulterant is Barium silicate.

Eg. Barium sulphate, calcium carbonate, Magnesium silicate and silica.

4. Why turpentine is used as solvents in paint extensively?

• Because of high solvent power, excellent flattening properties and ideal rate of evaporation.

5. Name the different types of paint.

1. Oil paint
2. Enamel paint
3. Latex paint
4. Alumunium paint
5. Acrylic polyurethane coating
6. Distemper
7. Varnish
8. French polish
9. Water wash and Colour wash
10. Miscellaneous paints

6. Types of paints, and explain.

Oil Paint: 

• Contains pigments usually suspended in linseed oil, a drier, and mineral spirits or other type of thinner.

Enamel Paint: 

• Consists of base like Zink oxide, ground in varnish with pigments for colour.

Latex Paint: 

• Consists of dispersion of fine particles of synthetic resin and pigment in water.

Epoxy: 

• Epoxy finishes are extremely hard, durable and excellent. 
• They can be used for protecting material such as steel, Alumunium and fiber glass.

7. Explain Varnish and its uses.

• Varnish is a homogeneous solution of resin in oil, alcohol or turpentine. 
• The oil dries with time and the other solvents evaporate leaving behind a solid transparent resin film over the surface.

Uses of Varnish:

1. Brighten the appearance of the grain in wood
2. Render brilliancy to the painted surface.
3. Protect applied surface from atmospheric action.

8. What is  White wash ?

• Fresh lime slaked with water is mixed thoroughly with water in a tub and then screened through a fine clean cloth. Thereafter, glue, dissolved in water, is added to it. 
• The surface is cleaned and the white wash is applied with jute brushes.

9. What is Colour wash ?

• A white wash when mixed with colouring pigment is called colour wash.

10. List out the characteristics of an ideal paint ?

1. Uniform spread as thin film
2. High coverage
3. Sufficient elasticity 
4. Impervious to air and water
5. Good workability and durability
6. Economy

11. List the sequence of painting process.

1. Surface preparation
2. Priming coat
3. Correction of defects or stopping 
4. Application of finish coats

12. Describe the sequence or procedure of painting on newly plastered surface?

Surface preparation:

• Before applying the paint, the surface is to be made free from dust, dirt, loose matter, grease etc. 
• It is rubbed with an emery paper or washed with detergents, to provide a mechanical key between surface and paint for satisfactory adhesion.

Priming coat:

• The Primer is applied with brush or spray on the prepared surface. 
• It should be thinned with water in the recommended manner and proportion before application.

Correction of defects: 

• After drying it is rubbed with an emery paper. 
• Dents and cracks filling nail holes, sealing knots and treating efflorescence if any, are corrected and then filled with putty using a knife applicator and rubbed down to smooth or rough surface.

Application of finish coats:

• Two or three finish coats are applied. 
• Each coat is allowed to dry before the application of next coat.

13. Defects on painted surface.

1. Chalking
2. Efflorescence
3. Glossy surface
4. Wrinkling
5. Fading
6. Fungus growth
7. Blooming
8. Peeling
9. Sagging

14. What is knotting?

• Knotting is done so that resin cannot exude from the knots. 
• Resin from the wood knots causes defects in painting such as cracking, peeling and brown discoloration. 
• Various methods of knotting are putty knotting, lime knotting, white lead knotting and shellac knotting.

15. Methods of knotting in wood painting work.

1. Putty knotting
2. Lime knotting
3. White lead knotting 
4. Shellac knotting

16. What is stopping in wood painting process ?

• After the priming coat, putty is applied to fill the pores of the surface. When putty is dried, then it is rubbed smooth. The process of rubbing sown the wooden surface is called stopping.

17. What are the tools used for painting?

• Brushes
• Rollers
• Painting compressor and gun 
• Sander
• Surface grinder
• Wire brushes
• Air blower
• Water jet surface cleaner

18. Paint is a liquid coating used to protect the surface from weather conditions.

19. Principal constituent of paint is Base.

20. Vehicle are also known as binders in paint.

21 From 0.1 to 5 microns are finely ground mineral, organic substance of metal powders their size ranges.

22. Pigments composition are used to hide surface imperfections and impart the colour of paint.

23. Solvents or thinner composition of paint are used to dilute the paints and increase the spreading power.

24. Solvents is the composition of paint are also known as thinners.

25. Adulterants substances are used to bring down the overall cost of paint and also known as inert fillers.

26. Oil paints contains pigments usually suspended in linseed oil, a drier, and mineral spirits or other types of thinner.

27. Traffic signs are generally painted with Fluorescent Paint.

28.  Driers are used for hardening of paints.

29. Varnish provide a protected coating and gloss to the surface and intensify the wood grains.

30. Epoxy Paint is extremely hard, durable, excellent and give tile-like finish.

31. French polish is prepared by dissolving the resin in methylated spirit at room temperature.

32. Distemper paint made with base as white chalk and thinner as water.

33. The best adulterant for paint is Barium Silicate

34. The excess use of Drier is affects the elasticity of paint leading to flaking failure.

35. Fading is the loss of colour in painted surface due to the effect of sun light.

36. A white wash when mixed with colouring pigments is called Colour wash.

37. Blow lamp device is used for removing by burning the old paint in old iron painting work.

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