---
title: "Ingredients of varnish"
subject: "Civil Engineering Materials"
chapter: 9
key: "semester_3/civil_engineering_materials:ingredients-of-varnish"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/ingredients-of-varnish
site: BCT Engineering
---

# Ingredients of varnish

Civil Engineering Materials · Chapter 9: Paint and Varnishes

- Asked in: 2079 Bhadra, 2 marks
- Video: [Varnishes, ingredients](https://www.youtube.com/watch?v=qiF9wvAl3_I) — CiviliAnZ VloG
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/ingredients-of-varnish
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-9

## Question

Define the ingredients of varnish.

## Short answer

Varnish consists of resin (natural or synthetic) dissolved in a solvent like turpentine or spirit. Oil varnishes also contain drying oil and a drier to speed hardening.

## Answer

Varnish is a solution of resin in a solvent, and its main ingredients are:

1. **Resin (gum):** Natural (lac, copal, rosin, amber) or synthetic resin. It forms the hard, shiny film on drying.
2. **Solvent (thinner):** Dissolves the resin and makes the varnish spreadable, and evaporates on drying. Examples: turpentine (oil varnish), methylated or wood spirit (spirit varnish), water (water varnish).
3. **Drying oil (in oil varnish):** Linseed or tung oil, which gives toughness, elasticity and durability.
4. **Drier:** Compounds such as litharge or manganese salts that speed up drying.
5. **Colouring matter (optional):** Dyes or pigments added to make coloured varnish.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the role of resin in varnish?
   A. Speeds up drying
   B. Dissolves the other ingredients
   C. Forms the hard shiny film on drying
   D. Gives colour only
   Answer: C. Resin (gum) forms the hard, shiny film when the varnish dries. (Key point: Resin)

2. Which solvent is used in spirit varnish?
   A. Turpentine
   B. Methylated or wood spirit
   C. Linseed oil
   D. Water
   Answer: B. Spirit varnish uses methylated or wood spirit; turpentine is for oil varnish. (Key point: Solvent)

3. Why are driers such as litharge or manganese salts added?
   A. To thin the varnish
   B. To speed up drying
   C. To add colour
   D. To dissolve resin
   Answer: B. Driers speed up drying. (Key point: Drier)

4. Which ingredient gives toughness and elasticity in oil varnish?
   A. Linseed or tung oil
   B. Dye
   C. Methylated spirit
   D. Lac
   Answer: A. Drying oils like linseed or tung oil give toughness, elasticity and durability. (Key point: Drying oil)