Final answer:
Air trapped between topcoat and primer can cause the paint to peel or blister.
Step-by-step explanation:
Air trapped between topcoat and primer can cause what is known as peeling or blistering of the paint. This occurs because the air expands and contracts at a different rate than the surrounding paint layers. As a result, pressure builds up and causes the paint to separate from the surface.
For example, if air is trapped between a layer of primer and a layer of topcoat on a wooden surface, the fluctuating temperature can cause the air to expand and contract. This leads to a buildup of pressure, resulting in the paint blistering or peeling off.
To prevent this issue, it is important to properly prepare the surface before applying paint and ensure that all layers are applied uniformly and without trapping air. This can be accomplished through techniques such as sanding the surface, priming with a thin and even layer, and using smooth and controlled brush strokes during the application of the topcoat.