Repurpose Gym Shorts Into A Backpack-Style Drawstring Bag

When your son goes out of his way and asks you to make him something, you stop everything and do it. Not because he's got you wrapped around his little finger, but because there aren't many opportunities to sew for a teenage boy. (I wanted to screen print a shirt for 8th grade promotion that said "I put the RAD in GRAD" which apparently is lame. At least he can be honest, and I can laugh at myself.). Anyway he asked me to make him a backpack. Um, a backpack? I said.  He meant a drawstring bag like I made for his gym clothes, but with straps that he could wear like a backpack, to use for the class trip to Six Flags Great America. I told him so long as the bag is used for good an not for evil, like transporting explosives (he is a good kid, but some kids brought fireworks -- actually M80s -- to his birthday party so now we are on alert).

I used a too-small pair of Nike basketball shorts (he was excited that I said I could get the Nike swoosh logo on the bag).  I carefully cut the drawstring out of the elastic waistband and repurposed that too.   

I cut off the waistband and cut out the inseam and cut new side seams to get a rectangle. Then I sewed the bottom and sides.

Before I made the drawstring casing, I put two buttonholes in front for the drawstring, and two buttonholes in the back to thread the "straps" through. (These pictures just show the back).

I got a cord stop so that the bag would stay closed.  They're easy to use - just pinch the button so the holes line up and thread both ends through.  Tie the loose ends in a knot so the stopper doesn't come off.

I already had some D-rings to anchor the straps at the bottom. I used part of the hem from the scraps to make a loop through the ring and sew into the bottom seam.

I got some cord at JoAnn for the straps - 3 yards of it which I thought would be way too much but was just about right.  The way I threaded them was to go through the buttonhole at the back of the bag, through a D-ring and back through the buttonhole, then through the other D-ring and tie or sew the loose ends together.  Just check it for size/fit before you do anything permanent.

You can even fiddle with the straps and wear it like a crossbody bag.  If you know a better way to thread the straps, please enlighten me!  It's the only way that made sense to me.

It's not fancy but I'm hoping it will get some use at the water park this summer or for P.E. in high school next year...  I feel like using the hardware -- the cord stop and the D-rings -- makes it feel like a "real" close-to-storebought bag and less of a homemade item.