Difficulty: Easy
Correct Answer: Resin, drying oil, and turpentine (or mineral spirits)
Explanation:
Introduction:Varnishes are classified broadly into oil varnishes and spirit varnishes based on the vehicle and curing mechanism. This item asks for the standard composition of an oil varnish as used for wood finishing and certain protective coats in buildings and furniture manufacture.
Given Data / Assumptions:
Concept / Approach:
Oil varnishes use a drying oil (e.g., linseed or tung) with resins (natural or modified) dissolved in a volatile solvent such as turpentine or mineral spirits. After application, solvent evaporates and the oil-resin system cures by oxidation and polymerization to form a durable film.
Step-by-Step Solution:
1) Identify key functional roles: resin = film former; drying oil = cures by oxidation; turpentine/mineral spirits = solvent.2) Exclude spirit varnish composition (resin + alcohol) as it is not an oil varnish.3) Exclude wax as it is not a standard primary component of oil varnish.Verification / Alternative check:
Coatings references list classic oil varnish compositions as resin + drying oil + hydrocarbon/terpene solvent, confirming option C as the correct combination.
Why Other Options Are Wrong:
Synthetic resin and spirit: That describes spirit varnish, not oil varnish.
Oil, wax, and resin / Spirit, oil, and wax: Wax is not essential and changes film properties; these are not standard oil varnish recipes.
Common Pitfalls:
Mixing up spirit varnish with oil varnish; assuming wax is a universal component; ignoring the role of the solvent.
Final Answer:
Resin, drying oil, and turpentine (or mineral spirits)
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