(As with all leather, remember to use a teflon presser foot and leather needles.)
1. Stretch spandex around a frame. Stretch only in 1 direction and pull as tightly as possible. Nail securely to frame. Check that frame fits between sewing machine’s presser foot and bobbin case.
2. Lay leather in frame and stitch. Distance between stitches determines the size of piping. I used ½" and my pipes are about ¼".
3. The bulk if the frame will make it impossible for stitches to run the full length and width if the fabric. Remove the fabric from the frame and pull it until it lies flat to do additional seams. I was able to sew about 2/3 of the fabric with a gap in the center from where my frame hit the inner wall of my machine.
4. Cut to pattern shape and sew into garment. I recommend basting around the edges before cutting.