Zippers have a reputation for being extremely difficult to sew, because if the zipper is misaligned, it will not work. Felt is a popular material for crafts and some clothing, but is also held with a negative regard by some sewing enthusiasts due to its tendency to jam sewing machines. Thus, sewing a zipper onto felt should cause double trouble, right? Wrong! With a little bit of patience and a hand-sewn technique, crafters can put any worries about these materials at ease.
Placing the Zipper
Close the zipper all the way and have the zipper face up. Sewing the zipper while closed will help ensure that the felt is sewn on straight.
Place a piece of felt on either side of the fabric strip of the zipper. The felt should overlap on top of the fabric of the zipper. The edges of the felt pieces should line up with the first teeth of the zipper (near the zipper's pull tab) and run down the sides of the teeth. Most other fabrics would be seamed first and then placed by the zipper, but felt is thick so seaming is optional.
Pin the felt to the zipper on each side with small straight pins. These will keep the fabric in place while you sew.
Sewing the Zipper
Sew along both sides of the felt, removing the straight pins as you go. Use a thread color that compliments the fabric and a needle that is appropriate for felt fabric. A needle that is too large will create unsightly, gaping holes in the felt.
Trim the zipper to the length of the fabric. At the desired spot on the zipper (along the edge of the felt), sew a "barrier" from one end of the zipper's fabric, over the teeth, and down through the other side of the zipper's fabric edge several times. This will create a thick wall of stitches across the teeth of the zipper so that the zipper pull does not slide off.
Run the needle back under the top of "barrier" thread and then out through the bottom. Do this several times until a woven pattern is created and tie it off with a knot. This is called a "bar tack" and it will prevent the zipper from running off of the teeth.
Cut off the remaining zipper with scissors so that it lines up with the length of the felt. Be sure to trim it off past the bar tack stitch so that the zipper remains intact after cutting off the extra length.
Open and close the zipper to ensure that it works properly.
It is much easier to sew felt by hand rather than with a sewing machine. Felt has a tendency to jam up a bobbin. If you'd like to be brave and put felt into a sewing machine, use a larger piece of felt (for easy feeding) and try putting a piece of tissue paper over it. The paper will help the needle in the machine grip the felt and sew without jamming.