Break through

The penetration of a coating onto the substrate refers to the undesired emergence of features or properties of the substrate through the applied coating. This can have visual, mechanical or functional effects and impair the quality of the coating. Typical causes are insufficient opacity of the coating, chemical interactions between the substrate and the coating material or mechanical stresses.

A common example is the show-through of substrate colors or structures when a coating is applied too thinly. Chemical reactions, such as the migration of substances contained in the substrate (e.g. wood tanning agents or moisture), can also lead to visible changes such as stains or discoloration. In some cases, adhesion problems can also arise if the substrate has not been properly prepared.

Careful substrate preparation, the use of suitable primers and the selection of suitable coating materials are essential to prevent bleed-through. The substrate should be cleaned, degreased and, if necessary, sanded to ensure optimum adhesion and coverage. Particularly for demanding applications, it is crucial to follow the manufacturer's instructions for layer thicknesses and application to ensure an even and opaque coating.