Fulling

Fulling is a textile finishing process applied to woolen woven fabrics to clean, thicken, and strengthen them by causing the fibers to interlock through moisture, heat, and physical agitation. The result is a denser, felted-like cloth with improved warmth and durability, and a more uniform surface.

Traditionally, fulling involved washing the woven fabric in vats with water and a cleansing agent (historically including soaps and, in some periods, urine for its ammonia content) and then applying mechanical action such as stomping, pounding, or mill-driven agitation. The combination of moisture, heat, alkali, and friction causes wool fibers to felt together at a controlled rate, reducing size and increasing cohesion. After fulling, the fabric is rinsed and treated to set its dimensions.

Fulling is commonly contrasted with felting of loose fibers: fulling finishes woven cloth by shrinking and densifying it, whereas felting generally refers to forming fabric directly from loose wool fibers. In the Scottish and Irish traditions, a related practice called waulking involved pounding and rubbing fulling cloth in a communal process, often with song and rhythm.

In modern textile production, fulling is typically achieved by mechanized methods in a fulling mill using controlled water, heat, and detergents or alkalis, and it may be followed by setting processes such as crabbing or finishing to stabilize the cloth’s dimensions. Some wool fabrics are finished with anti-shrink or sanforization processes to control subsequent shrinkage while preserving the desired texture.