The detachment of the paint film from the surface is known as ..........
Understanding Paint Film Failures
A dried layer of paint is called a paint film. For a paint job to be successful, this film must remain intact and firmly attached to the surface (substrate). Various environmental factors and application errors can cause the film to fail in different ways. This question asks to identify the specific term for when the film lifts off the surface.
📝 Detailed Analysis of the Options
(a) Chalking
Description: This is the formation of a fine, loose powder on the surface of the paint film.
Cause: It's caused by the degradation of the paint's binder due to exposure to UV radiation (sunlight) and moisture. The binder breaks down, leaving the pigment particles unbound. The film itself is still attached, but its surface is deteriorating.
(b) Cracking
Description: This is the splitting of the paint film. It can manifest as fine lines (crazing) or larger, interconnected cracks (crocodyling or allgatoring).
Cause: Cracking occurs when the paint film becomes brittle and can no longer expand and contract with the substrate. This can be due to aging, applying a hard topcoat over a softer primer, or using too much drier. Cracking is a failure *within* the film, but it is often a precursor to flaking, as moisture can get under the cracked film.
(c) Flaking
Description: This is the correct answer. Flaking is the physical lifting and detachment of pieces of the paint film from the underlying surface. It is a complete loss of adhesion.
Cause: Flaking is the ultimate result of poor adhesion. This can be caused by painting on a dirty, wet, or greasy surface; moisture getting behind the paint film (often through cracks); or applying a new coat of paint over a previous one that was not sound (e.g., was chalking or flaking itself).
(d) Wrinkling
Description: This is when the paint surface develops a rough, puckered, or wrinkled texture.
Cause: Wrinkling occurs when the top surface of the paint film dries much faster than the layer underneath. This is common when paint is applied too thickly, or when painting is done in very hot weather or direct sunlight. The top skin forms and then shrinks, pulling the still-wet paint underneath into wrinkles.
📊 Common Paint Defects
| Defect | Description | Primary Cause |
|---|---|---|
| Flaking | Film lifts and detaches from the surface | Loss of Adhesion |
| Cracking | Film splits, but remains attached (initially) | Brittleness, Stress |
| Chalking | Powdery residue forms on the surface | Binder Degradation (UV) |
| Wrinkling | Surface becomes rough and puckered | Uneven Drying |