A felting tool is an implement used either for wet felting, or the process of transforming woolen fiber into a dense, felted fabric, or needle felting, a dry felting technique that achieves similar ends. For wet felting, the tools used are usually abrasive implements that create friction with wet fibers, such as a washboard or a modern washing machine. Needle felting uses a special felting tool in the form of a barbed needle, to create the same friction without the need for water. The craft also uses a piece of foam or other spongy material and may also require the use of a hand carder, a hand-held tool used to clean and prepare fiber for felting.
Wool-like animal fibers are the only types of fibers that can be felted using the wet felting process, because there are microscopic scales coating each strand of these fibers. When exposed to water, particularly very hot or very cold water, and gentle soap, the scales open up. If the fiber is agitated, the opened scales will latch onto each other and create a single piece of condensed fabric called felt. Felting can be done completely by hand or using a simple felting tool like a wooden spoon, but felting this way is very time-consuming and also requires strength and stamina. It is more common to employ a felting tool that helps create friction, such as a washboard.
The craft of needle felting is usually used to embellish objects, such as bags, or to create detailed three-dimensional objects like felted toys. It is similar to wet felting in that it uses the same principal of applying friction to wool-like fibers to create felt. Unlike wet felting, however, needle felting does not require the use of water. Also, wet felting can only be performed on raw fiber that has not yet been spun, whereas needle felting sometimes uses already spun yarn.
To create enough friction to cause the scales on a strand of wool to hook together, needle felting employs a felting tool, a needle with many barbed points. When needle felting a flat piece, such as an applique, onto an already knitted or crocheted object, the object is laid flat with the applique on top of it. A piece of foam or a special brush-like needle felting mat is placed on top of the applique. The needle is then poked repeatedly through the foam in a vertical motion, which forces the barbs on its points through the layers of fiber, hooking them around each other to create felt. When needle felting a three-dimensional toy, the barbed needle is used like a sculptor's chisel to mold and shape the fiber.