How to Stiffen Wool Felted Hats By: Eric Watson Updated On: October 23, 2017 More Articles How to Waterproof a Felt Hat How to Sew Knit Fabrics on a Sewing Machine How to Wear Skinny Jeans How to Wear a Wig for Crossdressers How to Shrink Leather Boots About the Author Eric Watson is a professional hatter with a custom hat shop in Cave Creek, Arizona.