Fulling is a variation of felting that uses knit or woven fibers rather than loose fibers. For this hat, I knitted 2 strands of worsted weight wool with eyelash and feather yarns. The decorative yarns were used to create interesting surface variation in texture, color change, and reflection of light.
I used 2 strands of wool throughout to give consistent body to the hat and create even fulling (wet felting). I made a graduated change in the wool coloring from taupe to burgundy by switching from 2 strands of taupe, to 1 each of taupe and burgundy, then to 2 strands of burgundy.
The wet fulling process uses hot water, soap, and agitation to cause the scales of the wool fibers to expand, migrate, and bond together. The knit stitches disappear creating a more dense, stronger, and more durable fabric we know as felt. As the fabric becomes more dense (thicker) there is a corresponding decrease in size. To allow for this decrease, I multiply the dimensions of my desired finished size by 140 to make the original knitted hat 40% larger than the finished fulled hat. You can see the difference in size and firmness of shaping in these before and after photos.

before and after fulling
This hat was fulled in my washing machine. I leave the lid open so the hot soapy water isn’t drained until I’m done. I check the size of the hat and stop fulling when it’s the right size. Rather than use the spin cycle which would distort the hat, I pull it from the water, place a rolled up small towel inside it, then roll the whole thing up in a larger towel, and squeeze it to remove the excess water.
The wet hat then needs to be stretched and pulled into shape. I used a wood hat block covered with plastic wrap to help me shape the hat. Before I owned a hat block, I used plastic pots and containers. I set it to dry on a flat topped plastic container that was slightly smaller so it wouldn’t distort the hat as it dried.
After the hat is dry, I gently comb the decorative yarns that stick out from the felted wool to fluff them.