Three kinds of felt are used in hats – fur felt, wool felt, and mixed felt.

Wool felt is the least costly to make and is used in a durable casual felt hats. Wool felt is made from sheep’s wool held together with steam, extreme pressure and chemical binding agents. Unless the hat is specifically treated for rain, wool felt does not hold crisply blocked shapes well after getting wet. It’s similar to hairspray holding a curl in your hair: if your hair gets wet, the hairspray dissolves and the curl falls out. If the chemical holding the wool fibers together gets wet, the fibers slip apart and the hat loses it’s shape. You can Scotch Guard some wool felt hats, but get your hatter’s opinion before you do so.

Fur felt is the most costly felt to make and is commonly used in fine men’s and ladies dress hats as well as durable outdoor hats like the Australian line of Akubra Hats. It is flexible, durable,tough in the rain, easy to clean and re-block into shape. Though the fur of choice in the past was beaver, today the most commonly used fur is rabbit. Contrary to rumour, rabbit fur felt can be of just as high quality as beaver fur felt, due to advanced techniques and developments in the felting process. Fur felt is held together by extreme pressure and steam. The interlocking barbs on the strands of hair hold everything together. There are no chemicals to fall out during rain. However, fur felt has a tendency to shrink when exposed to rain, so unless the milliner selling you the hat has said otherwise (or you feel comfortable streching it out again), keep contact with rain to a minimum.

Mixed felt hats often have the best of both worlds, being made of both wool and fur. They are priced between wool and fur, have the soft hand of fur, are highly flexible, easy to clean and often made to withstand rain and travelling. The felting process used is the same, as with wool felt hats, but with fewer chemicals needed to hold the fibers together.