I piece batting all the time because I buy it on a 44" wide bolt and have to piece together at least 2 pieces to make a quilt. I started out sewing the pieces together, but I saw a post from someone here on the QB about using fusible interfacing to piece them together and have been using that ever since. I really like it a lot better because it's faster to me and I always seemed to have trouble sewing the two pieces together with a zigzag because the right side would always creep forward more than the left side when sewing. When using the fusible interfacing, I just cut off a strip about 1.5" wide and iron it across the seam. I only need it on one side just to hold the pieces together until I quilt it.