The microscopic scales that cover individual filaments of animal hair are responsible for the fibers' unique ability to mat or felt together. Felting occurs when the fiber is moist and physically agitated and is enhanced by a change in the neutral pH to either acidic or alkaline conditions and the application of heat. With warm water and soap these scales swell open, causing the filaments to snag and interlock with one another when agitated. This knotting causes shrinkage, resulting in dense, strong felted fiber. Matting happens naturally overtime, as evident in the hair of pets or in the hair of humans that has not been brushed. Based on archeological findings from the Central Asian Steppes intentional felting of animal hair by humans has been a means of creating unwoven fabric for clothing, shelter, and artistic expression since at least 600 BC, with further evidence suggesting even earlier knowledge of the process.
Although most animal fiber felts (aside from qiviut or muskox), select animals and specific breeds felt more quickly than others as well as varying in coarseness; finer wool fibers are generally used for wearable items due to their softness against our skin, while courser fibers are used for more utilitarian purposes as they are more durable and pill less. Additional fibers that alone would not mat such as silk, cellulose fibers and even synthetics can be blended in small proportions to these animal fibers to create felt, as the animal fibers will intertwine and mat around them. Primarily using wool from Merino sheep, I begin with either washed locks of fleece that I naturally dye and then card and felt or carded wool that I felt into fabric and then apply the color through a submersion dye bath.
I felt two-dimensionally by first stacking thin sheets of fleece to a desired thickness, then dampening and compressing the wool with soapy water. This wool sheet is then rolled up in a bamboo mat or in a sheet of bubble wrap and rolled so the ridges or bubbles gently agitate the fibers into knotting. When the fibers have felted or intertwined to create a stable piece of fabric, the felt can then be fulled or thickened and strengthened by more roughly agitating the fabric on a coarsely ridged surface such as a washing board or rubber door mat to encourage further tightening of the knotted fibers. To felt three-dimensionally, I either agitate the fleece free form in my hands to create solid wool objects or wrap layers of fleece around flat or form resists, which are then removed after the fleece has been agitated into felt, leaving a felted vessel that can be further sculpted by fulling specific areas. The fulling technique can also be applied to spun yarns consisting of specific animal fibers that have been knitted, crocheted or woven in order to shrink and thicken the original structure.
The clarity of line, intricacy of pattern and realism of felted designs as well as the variety of surface textures depends on the innovations of the felt maker. When working with fleece the staple or length of the individual hair filaments can limit the definition, shape and size of surface designs. By creating sheets of partially felted fleece, one can cut out shapes of varying color, edge quality, shape and size and felt them onto a background of fleece, thus enhancing artistic control. In order to achieve this advanced technique the initial felting process must be stopped when the hairs are intertwined enough so that the cut shape will hold together, but while there are still enough loose fibers so that the shape will felt to the loose fibers of the background. Surface textures can be created in the felting process by varying the density of fleece, incorporating yarns and non-felting fibers, embedding solid wool forms or other objects and fusing the wool through pre-structured mediums such as fabric. Commonly referred to as nuno or laminate felting, fusing initially coerces the hair filaments through the spaces in the substrate after which continued agitation felts the two materials together creating an new textile. Due to the differential shrinkage of the wool fibers and the material fused through, the fleece will continue to shrink, crinkling the fabric into textural variations. Additionally, machine and hand stitching, beading and needle felting can alter the surface texture of the felt.
There are various techniques employed to create felt, some ancient and others that utilize advances in technology. Traditionally, felt was made while wet, rolled up in either a reed mat or animal skin and with human labor, though animal power had also been utilized to assist in the agitation process. Contemporary felt makers now have access to electric felting/fulling machines that agitate the fleece into felt, commercially produced needle felted pre-felts for design, and household needle felting machines and tools that allow for dry felting of fiber both two and three-dimensionally without the addition of water. A felting needle has barbs cut into its metal shaft allowing the needle to snag and intertwine filaments (even synthetic fiber) when forced through layers of loose fiber. Artisans may work wet or dry or combine the processes until they achieve their desired effect. I consider myself a wet felter as I always finish with wet felting, though I occasionally use needle felting for tacking or stabalizing dry prepared 3-D forms prior to wet felting and for the addition of fine details.
Though the process of felting does not necessitate exceedingly expensive materials or equipment and just about anyone can add soapy water to fleece and agitate it into a felted mass, control of the outcome and well crafted, quality felt is achieved through years of experience and learning. Aside from choosing the best type of fiber for the application, one needs to consider the lay out of fibers for consistent felt, the weight of wool in relation to the area of its distribution to determine shrinkage and shaping through the fulling process, the amount of soap to use to assist in and not deter the process, the temperature of water and rate of agitation at varying steps inthe fusing and felting process, when to cut felt to allow for well seamed edges, how to incorporate cut fabric edged and selvedges for refined finishing when fusing fleece through fabrics and when a felt is stable and finished to avoide surface pilling and destabilizing of the felt through wear and use. In additionto craftsmanship of the material process, one also needs to consider the manipulation of the material through the elements of art and principles of design in order to communicate ones aesthetics and concepts visually.