Zippered welt pocket in a side seam

I've returned to an earlier project, the Marfy shorts.  Thank-you to Belinda, Jenny, Christine and Mem for helping me out with my Marfy pattern puzzle.  The consensus is that the lower half of the patch pockets have a vertical zippered opening.  Whilst I was thinking how to do this, I pulled out some King Gee shorts.  I have learnt a few construction techniques by studying King Gee clothing.  One of the pairs of shorts had a zippered welt opening in a side seam.  This would be on the opposite side of the pocket than the Marfy pattern indicated, but I decided to try this technique out anyway.

I took some photos of my practice run.

The brown fabric is the main fabric.  I have interfaced the edge, to a width of about 5 cm.  The floral fabric will become the welt.  This welt fabric should be interfaced.

Mark the welt position on the main fabric.  The box is a width of 2.5 cm (1.5 cm seam allowance plux 1 cm welt width) and the length of the zipper opening.  I have marked a basting line 1 cm (welt width) away from the box.  I have also marked the cutting lines, 1 cm inside the box.

 Place the main fabric and the welt fabric right sides together, lining up the edge.

 Baste along the basting line ouside of the box.

 Press the welt fabric up along this basting line.

 Stitch along the long side of the box, stopping and starting exactly at the ends of the box.

 Trim the excess fabric away along the cutting lines in the box.  Cut diagonal lines into the corners of the box.

 Turn the welt to the inside.

 Fold back the ends of the main fabric and stitch a short vertical line to secure the ends of the welt.  Repeat for the other end of the welt.

 Fold the welt over the main fabric so that the seam allowances are exposed.

 Place the zipper face down on these seam allowances.

 Change your machine foot to a zipper foot and baste the zip in position, making sure that you do not catch the welt or the main fabric panel in the stitching.

Sandwich the zip between the seam allowances and the pocket lining.  (The pocket lining should be twice the depth of the pocket plus seam allowances. )  Stitch.  After sewing most of the zip, you may need to stop the machine with the needle down, lift the foot, pull up the zipper tab, lower the foot and continue sewing.

 Press back the pocket lining.

 This is what is looks like from the right side.

 Fold the pocket lining in half, forming the pocket.  I handbasted the other side of the zipper in place along the seam line, so that I could see and sew the seam line without catching the welt.

 Place another main panel on top and sew the side seams of the garment.  All done.

I haven't sewn the ends of the pocket bag in this example.  On the shorts I will sew the pocket bag by topstitching through the main panel.

Now for the real thing.  Wish me luck!