Exterior fabric: One old sweater! I love to use recycled woolen sweaters which have been felted (slightly shrunk and the fibres have bonded together). Notes on how to felt a sweater are below. Otherwise use any soft warm fabric for the exterior.
Lining: Cotton, soft linen, flannelette or other soft breathable fabric.
I use recycled wool sweaters to make these hats, but if you are purchasing fabric you will need 3/4 yard (70 cm) of 44” (115 cm) wide fabric of both lining and exterior fabric. This will probably be enough to make more than one hat, depending on the size you are making.
To start with, you need to source a sweater made from natural animal fibres, such as wool, mohair, cashmere, angora, or merino wool. Check that the percentage of natural fibres is at least 80%. If it is less than 80%, it will not felt. It will also not felt if it is “superwash wool”.
Wash your sweater on a HOT wash using a regular laundry powder. You do not want to use a gentle wool cycle or wool detergent as they are designed NOT to felt your wool! You may need to put it through a hot wash twice. If you have a dryer, that will also help felt your sweater, especially if used on the hottest setting.