Choose a Binding
I used a polyester knit seam binding because that is what I had around. Having a knit binding is important because you need to stretch the binding around the thick sweater edge. I'm sure you could do it with a woven, but you'd need to make sure it's pretty wide to take the sweater thickness into account. Make sure you have enough binding before you start sewing. Don't trim it until you have sewn it on.