Wet felting is one of several methods which can produce felt from wool and other animal fibres. Warm soapy water is applied to layers of animal hairs placed at 90 degree angles to one another. Repeated agitation and compression causes the fibres to hook together into a single piece of fabric. Wrapping the properly arranged fibre in a sturdy, textured material, such as a bamboo mat or bubble wrap, will speed up the felting process. After the wet felting process is complete, the felted material may be finished by fulling.
Only certain types of fibre can be felted successfully. Most types of fleece, such as those taken from the alpaca or the Merino sheep, can be put through the wet felting process. One may also use mohair (goat), angora (rabbit), or even dog hair. These types of fibre are covered in tiny scales, similar to the scales found on a strand of human hair. Wetting and soaping the fleece causes the scales to open, while agitating them causes them to latch onto each other, creating felt. Plant fibres and synthetic fibres will not felt.
There are two famous artists who use wet felting as their media for their artwork pieces that are well known these days: one of them is Nicola Brown, who uses this style of art in order to create decorative landscapes for children novels and the other one is Claudia Jean Nelson, which uses this style of art for a different reason; her reason is to create all kinds of different imaginative dresses (for exposition) and other decorative ornaments (such as bags, teddy bears, wall decorations and book cover decorations).
Needle felting is a popular fibre arts craft that creates felt without the use of water. Special needles that are used in industrial felting machines are used by the artist as a sculpting tool. While erroneously referred to as "barbed" needles, they in fact have notches along the shaft of the needle that grab the top layer of fibres and tangle them with the inner layers of fibres as the needle enters the wool. Since these notches face down towards the tip of the needle, they do not pull the fibres out as the needle exits the wool. Once tangled and compressed using the needle, the felt can be strong and used for creating jewellery or sculpture. Finer details can be achieved with this method using a hand-held tool with either a single needle or a small group of needles (2-5), so it is popular technique for producing 2D and 3D felted work.
From the mid-17th to the mid-20th centuries, a process called "carroting" was used in the manufacture of good quality felt for making men's hats. Beaver, rabbit or hare skins were treated with a dilute solution of the mercury compound mercuric nitrate. The skins were dried in an oven where the thin fur at the sides turned orange, the colour of carrots. Pelts were stretched over a bar in a cutting machine, and the skin was sliced off in thin shreds, with the fleece coming away entirely. The fur was blown onto a cone-shaped colander and then treated with hot water to consolidate it. The cone then peeled off and passed through wet rollers to cause the fur to felt. These 'hoods' were then dyed and blocked to make hats. The toxic solutions in the dye and the vapours it produced resulted in widespread cases of mercury poisoning among hatters, possibly giving rise to the expression "mad as a hatter".