schilfering

Schilfering is the tendency of a surface to shed small, thin flakes from a coating, laminate, or surface layer. In Dutch technical usage, the term covers phenomena in which outer layers detach from a substrate, producing visible flakes or fissures. The effect can occur on metal, wood, glass, ceramics, polymers, and composites, and is particularly noted in protective or decorative coatings such as paints, varnishes, enamel, or laminated films.

Causes include poor adhesion between the coating and substrate, mechanical damage, moisture ingress, thermal cycling, UV radiation, chemical attack, and mismatches in thermal expansion or stiffness between layers. Environmental stresses can accumulate, leading to cohesive fracture within the coating or interfacial delamination at the coating-substrate boundary. The exact mechanism—whether predominantly adhesive failure, cohesive failure within the coating, or a combination—depends on material properties and service conditions.

Typical manifestations are lifting of edges, blistering followed by flake detachment, and the appearance of fissures radiating from defects. In conservation and restoration, schilfering is a common concern for painted surfaces and gilding, requiring careful surface preparation and compatible consolidation strategies.

Mitigation relies on proper surface preparation, appropriate primer and binder selection, matching mechanical properties of layers, controlling humidity and temperature, and using flexible coatings for substrates subject to movement. Standard adhesion tests, such as cross-cut tests and pull-off tests, are used to assess susceptibility to schilfering.

Understanding schilfering is important in construction, industrial coating, and heritage conservation to predict service life and guide maintenance decisions.