- 2078 Bhadra · 2 marks
Defects in paints
Short answer
Blistering is bubbling from trapped moisture or damp substrate. Flaking/peeling results from poor preparation or dampness. Cracking and crazing appear from ageing or a hard coat over a soft one. Chalking is a powdery surface from binder decay under sun. Fading is colour loss from sunlight or chemical action.
Explain any four defects in paints.
Common defects in paint work:
- Blistering: Bubbles in the film caused by moisture or gas trapped under the paint, or by painting on a damp surface.
- Flaking (peeling): Paint comes off in flakes because of poor surface preparation or dampness.
- Cracking and crazing: Fine cracks caused by ageing, unequal drying rates, or a hard coat applied over a soft one.
- Chalking: A powdery surface caused by decay of the binder under sun and weather.
- Fading: Loss of colour due to sunlight or chemical action.
- Sagging (running): Paint flows down in curtains when it is applied too thickly or has been thinned too much.
- Wrinkling: The top surface dries and forms a skin before the paint below it has dried, so the film wrinkles.
- Bloom and grinning: A dull, cloudy film (bloom), or the earlier coat showing through because of poor covering power (grinning).
✓ Answer checked by Claude Opus 5.5 (high effort)
Related questions
- Defects caused by seasoning · Civil Engineering Materials, chapter 7
- Common acoustic defects · Building Technology, chapter 1
- Solidification, shrinkage and casting defects · Manufacturing and Production Processes, chapter 4