Assemble Bag Body
1. Join bag panels along top edges with a 1/2" seam allowance, machine-stitching with a regular-length stitch (10–12 stitches per inch) for 1/2" at the beginning and end of the seam and machine-basting in between (Diagram 7).
2. Place joined bag panels right side down on a terry cloth towel (to protect dimensional trims) and press seam open.
3. From bag panels’ wrong side, center and align zipper facedown on pressed seam allowance. Using a zipper or cording foot, sew zipper to joined bag panels through all thicknesses. Remove basting stitches. From right side, open zipper.
4. Join bag panels along side edges with 1/4" seam; sew bottom edge with 1/2" seam to make bag body. Press seams open.
5. To shape flat bottom for bag, at one corner match bottom seam line to side seam line, creating a flattened triangle (Diagram 8). Measuring 2-1/4" from point of triangle, draw a 4-1/2"-long line across triangle. Sew on drawn line. Trim excess fabric, leaving 1/4" seam allowance. Repeat with remaining corner.
6. Following manufacturer’s instructions, press 4-1/2"x7" piece of fusible web onto 4-1/2"x7" piece of heavy interfacing. Peel off paper backing. Align interfacing, fusible side down, with flat bag bottom; fuse. Allow to cool. Turn bag body right side out and press.
7. Turn one end of handle under 1/2" and thread an additional 1" through a D-ring. Stitch folded edge to handle. Repeat with the other handle end and D-ring on opposite side of bag.