A common material used to make hats is wool felt. Felt is used to make hats such as derby bowlers, cloches, and fedoras. Unlike most fabrics, felt is not woven. Instead, it is made by compressing fibers and applying pressure, heat and moisture. A blend is also created with wool and synthetics fibers, which makes the material more durable. Wool felt can be dyed to provide color, and works well as a liner or padding.
Not only is wool felt used for hats, it has many other purposes as well. This includes boot linings, helmet padding, framing paintings, storytelling boards for children, puppets, and in pianos.
Wool felt has many beneficial properties. Due to the fact that it is not woven, the material will not fray or ravel if it is cut or torn. It is flame retardant, as well as chemical resistant. Wool felt is a great thermal insulator, as well as a sound insulator.
Fact: Historically, many milliners developed erethism, more commonly known as "Mad-Hatter Disease". This is a long-term exposure to mercury (which was used in the 1800's to make hats), causing mercury poisoning. This caused the exposed milliners to experience psychosis and other traumatic symptoms and illnesses.