We tie our quilts made by our church sewing ministry with double crochet thread, using a square knot or surgeon's knot. We've found that large curved upholstery needles work well. It works well to hand sew the thread in several locations and go back and tie them all. It saves us a little time. We also put a knot every 4 - 6". Joann's has a huge ball of white crochet thread (No. 10?) that we put on a dowel mounted to a base so we can just pull the thread off easily.