I've used flannel many times for binding, since I make a lot of flannel quilts. I've always done my flannel binding a little wider than I make regular cotton binding; 2 1/2"-2 3/4" i starch my flannel well Before cutting. I fold it in half, press then attach as normal, machine stitched to front with a 3/8" seam ( just a bit wider than 1/4" ) fold to back and hand stitch. So far even ones 15 + years old have held up. I do purchase really good quality double sided flannels.