The wet film is spread and leveled from walking until it loses effective fluidity. Spreading and leveling are driven by surface tension, including the surface flow caused by the difference in surface tension between the surface layers. This surface flow is not conducive to complete leveling and forms coating defects. Surface tension can cause several coating defects, including shrinkage craters, orange peel, floating color, thick edges, poor adhesion to substrates, bubble marks, pinholes, etc. The various disadvantages are described below.
Shrinkage cavity
orange peel
floating color
Thick edge
Shrinking and showing corners
Poor adhesion to substrate
bubble marks
pinhole
"Broken Curtain" in Curtain Coating
