Yesterday, I left a comment on Tanit-Isis's blog about bound pockets with buttons.
I realised later how hard it is to explain such a fairly simple addition without showing it.
So, I'm showing it here. In fact, I'm surprised about how many unbuttoned bound back pockets there are out there, both in RTW and in sewing patterns. I've made those twice myself and I always get annoyed by the pockets pulling up whenever I sit down and staying up.
There are two ways to add a button closure to a bound pocket:
with a buttonhole, usually used with a single welt
and with a little loop, used exclusively with a double welt.
Mine is wrong, the loop should come out from between the welts. When starting on the pocket, I put my loop between the trouser piece and the strip of fabric which was to become the welt, instead of on top of it. I didn't notice until I had cut the pocket and decided to leave it like this.
If you've made bound pockets before, neither of these is very hard to do but unfortunately, both require planning ahead.
As mentioned above, the loop should be inserted right at the beginning of pocket construction, when sewing the welt-strips.
The buttonhole should be added a little later. This is my test for the first single welt pocket I ever made. It shows the stage at which the buttonhole has to be made.
The welt is in place, the pocket has been cut and the actual pocket pieces have been attached to the top and bottom of the pocket opening. They are not yet attached to each other at the sides. Now, you can make a buttonhole in the outside fabric and the pocket piece attached to the bottom of the pocket. Then, you attach the button to the other piece and finish sewing the pocket.
I guess it would be possible to make a hidden buttonhole by only making it in the pocket piece. However that is the piece which is always made from lining fabric so it would kind of defeat the original purpose of the button (which is keeping the pocket neatly in place. the lining fabric would just be pulled up by the back of the pocket). And most buttonhole feet would not be able to cope with the stacked seam nearby (when make the visible buttonhole, you're placing the foot on top of it, making it invisible, you would have to fold the pocket bits in a way which makes the seam allowances at the bottom of the pocket stand up).
I hope this is useful. Let me know if anything needs clarifying.