(Submitted by Marje Rhine, technical pattern editor for American Quilter magazine)
Want to use up small leftover pieces of batting? I like to join them for use in doll quilts and wallhangings, but needed a quick method for joining the pieces so they would lie flat without a bump, instantly giving away the secret that they had been pieced. I tried butting straight edges of the pieces together then stitching together with a zigzag that catches both pieces. This worked OK but the batting tended to stretch as I sewed (photo left).
I've come up with what I think is a better method. Layer the batting, right-sides together (or same-sides together) along the straight edge (photo right). Using a short and narrow blind hemstitch, sew the pieces together. The straight lines of the blind hemstitch should run just along the raw edges of the batting with the occasionally right-left stitches catching both pieces. Open up the batting and pull slightly. The stitching should hold the length of the seam and almost disappear both visually and to the touch (photo below).