I made a pair of shorts to take on holiday with me (check them out here!) - and they have cute single welt pockets on the back. The pattern's instructions for these pockets were pretty easy to understand - but the result left me cold. I went searching through my books and online sources - and after a few different attempts using calico scraps, I came up with a result I was happy with.
This 101 is a bit long winded purely because I found from all of the examples I could get my hands on they glossed over parts I wished they'd had more information on! Here's how I did it:
1. Apply your interfacing strip to the wrong side of your fabric, approximately centered over the location where your welt pocket will be.
2. Grab your welt, and draw the height and width of the welt pocket you want to end up with on both the interfacing and the welt on the 'wrong' side of the fabric. Mine in this case is 12cm long and 1.7cm wide. On the welt piece I've drawn the rectangle in approximately the upper third of the welt - I'll show you why further on.
3. Pin the welt to the fabric, with the rights sides facing:
4. Sew along the upper and lower welt pocket lines in your shortest stitch - making sure your seam starts and stops exactly at the corner of the rectangle:
5. Take a sharp, pointy pair of scissors and cut a slit in the middle between the two seam lines just sewn:
Cutting through both layers of fabric (the garment and the welt piece), stop about 1.5-2cm short of each end to cut a fairly sizeable 'Y'. Get as close to the corner and stitch line as you dare - the closer you get the better the end result:
6. Grab your iron and press the welt upwards on the lower seam:
and then down on the upper seam:
7. Push the welt pocket through the cut you made in step 5:
8. Turn over so the 'wrong' side is facing up, and press the welt top and sides (not the bottom) so that the seam line is just on the inside fold:
Then underneath the unpressed welt bottom seam - press open the seam here (it reduces bulk for the steps a bit further on):
9. Taking the larger portion of the welt that is underneath the lower seam - fold this up so that the fold meets the top of the welt pocket and press flat:
Drawing the welt's rectangular outline in the top third of the welt piece allows us to make the welt out of a single piece of fabric, rather than making a window (similar to than in a bound button hole) and then using another fabric piece to make the welt. It will now look approximately like this from the front:
10. With the right side facing you like in the photo above, fold over the side to expose the welt pocket piece and the little interfaced triangle. Sew down and across the triangle - staying close to the original line you drew:
Then repeat on the other side.
11. Nearly there! Now we've finished the welt, it's time to attach the pocket. This also helps to 'stabilise' the welt to minimise any sag. With the right side of the pocket facing down, line up the edge with the bottom of the welt. I've placed mine a bit higher so you can see the welt underneath:
Pin in place, making sure you include the bottom half of the pressed-open seam underneath. Then sew across all of this:
12. Iron the pocket bag back down:
13. I've cut my pocket bag long enough allowing me to fold it up so the other end aligns with the waist-band seam of the garment. This also helps to stabilise the welt and pocket bag.
14. Pin the pocket bag to the welt fabric, but not the garment fabric. Sew first to the top of the welt, making sure you include the trapezium-shaped interfaced fabric:
Then sew down the sides of the pocket bag:
When you sew on the waistband (or lining) the top of the pocket bag will be included in this seam, supporting both the pocket and the welt.
And we're done!