Correct Answer: C. Powdered chalk and raw linseed oil
Solution:
Traditional painter's putty is a simple mixture used for filling small cracks, holes, and joints. It is made by mixing a fine powder, the base, with a drying oil. The standard composition is powdered chalk (whiting) mixed with raw linseed oil to form a stiff paste.
Correct Answer: B. Waterproof cement paint
Solution:
Snowcrete is a brand name for a type of white Portland cement. It is often used as the base for creating white or brightly colored concrete and mortars. When used in paint formulations, it forms the basis of a durable, waterproof cement paint, suitable for exterior masonry surfaces.
Correct Answer: D. White
Solution:
Zinc oxide is a widely used pigment in paints, known as zinc white. It provides a clean, bright white color and also offers benefits like mildew resistance and corrosion inhibition.
Correct Answer: C. Coloured cement
Solution:
Snowcem is a well-known brand of exterior waterproof cement paint. It is essentially a specially formulated coloured cement mixture that is mixed with water before application to provide a durable and decorative finish on masonry surfaces.
Correct Answer: C. Oil varnish
Solution:
Oil varnish, which uses a drying oil like linseed or tung oil as its vehicle, is the most durable and stable type of varnish. It cures through oxidation to form a tough, flexible, and weather-resistant film, making it suitable for both interior and exterior use. Spirit varnishes, by contrast, are harder but more brittle.
Correct Answer: D. All of the above
Solution:
All the statements correctly describe the properties of natural resins used in coatings:
A. They are hydrophobic and not soluble in water.
B. They are typically soluble in organic solvents like spirit (alcohol).
C. They are the primary film-forming ingredient used in varnishes.
Therefore, all of the above are correct.
Correct Answer: C. Both (a) and (b)
Solution:
Thinners are used to reduce the viscosity of oil-based paints to make them easier to apply. Both turpentine (a traditional solvent derived from pine trees) and naphtha (a petroleum distillate, also known as mineral spirits) are common and effective thinners for oil paints.
Correct Answer: B. Colour
Solution:
The primary function of a pigment in paint is to provide colour and opacity (hiding power). While the choice of pigment can influence durability, its main role is visual. The binder is primarily responsible for durability and the overall finish (smoothness/gloss).
Correct Answer: C. White lead
Solution:
Historically, white lead (basic lead carbonate) was the most common base for oil paints, especially for exterior timber. It was valued for its opacity, durability, and flexibility, which helped prevent the paint from cracking as the wood expanded and contracted.
Correct Answer: C. Aluminium oxide
Solution:
Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant finish. For aluminium, this process thickens the naturally occurring protective layer of aluminium oxide, making it much harder and more resistant to weathering.
Correct Answer: C. Solvent
Solution:
Methylated spirit (alcohol), naphtha (mineral spirits), and turpentine are all volatile organic liquids used to dissolve the binder and adjust the viscosity of paint. Their function is to act as a solvent or thinner, which evaporates after the paint is applied.
Correct Answer: C. Thinner
Solution:
A volatile substance is one that evaporates easily. A diluent is a substance used to reduce the concentration or viscosity of a liquid. In paint, the volatile diluent is called a thinner (or solvent). It makes the paint easier to apply and then evaporates, leaving the solid paint film behind.
Correct Answer: B. Blistering
Solution:
Blistering occurs when moisture or solvent gets trapped beneath a paint film. When the surface is heated (e.g., by sunlight), this trapped liquid vaporizes, creating pressure that pushes the paint film away from the surface, forming bubbles or blisters.
Correct Answer: C. Base
Solution:
The base is the primary solid component of the paint that forms the body of the paint film. Metallic oxides like white lead, zinc oxide, and titanium dioxide are commonly used as bases. They provide opacity and durability to the paint.
Correct Answer: C. Stopping
Solution:
In painting terminology, stopping is the specific process of filling imperfections such as nail holes, cracks, and dents with a filler like putty to create a smooth, uniform surface before applying the primer and paint coats. Knotting refers to sealing knots, and caulking is for sealing larger gaps or joints.