Avfetting

Avfetting is a preparatory cleaning process used to remove surface oils, fats, waxes, and other contaminants from a substrate before coating, bonding, or conservation work. The term is of Swedish origin and is often used in Scandinavian industries; functionally, it is equivalent to the English term degreasing or defatting. Avfetting is applied across a range of contexts, including metalworking, woodworking, painting, and the conservation of artworks and historical artifacts.

Processes used in avfetting include chemical, alkaline, and mechanical methods. Chemical degreasing relies on organic solvents such as mineral spirits, acetone, or isopropanol to dissolve oils. Alkaline degreasing uses detergents in hot water or alkaline baths to saponify fats. Mechanical methods involve scrubbing, brushing, or gentle abrasion. In some industrial settings, vapor or ultrasonic degreasing is employed to enhance cleanliness while protecting sensitive surfaces.

Applications of avfetting span several industries. It is commonly used to prepare metal surfaces for plating or painting, to condition wood or composite materials for coatings, and to clean artworks or artifacts during conservation. In painting and wood finishing, avfetting improves adhesion of primers and finishes and reduces the risk of coating defects such as blistering or delamination.

Safety and environmental considerations are important in avfetting. Solvent-based methods require adequate ventilation and proper handling of flammable liquids, while waste must be disposed of in accordance with local regulations. The choice of method depends on substrate sensitivity, the required level of cleanliness, and environmental or regulatory constraints.

See also: degreasing; surface preparation; conservation science.