Unfold your two shorts pieces. If you want to add any appliques to the shorts, now is the time to do it while they’re the easiest to sew on. If there’s an interesting graphic on the upcycled T-shirt that you’d like to use, cut it out and sew it directly onto the shorts. The edges won’t ravel, so you don’t have to turn them under or finish the raw edges in any way.
Re-fold the shorts pieces with right sides together, and pin each piece from the bottom finished hem up to that sticky-outy butt point–these will be the legs of your shorts. Sew both the legs up using any stitch suitable for jersey knit.
Leave one shorts leg inside-out, and stuff the right-side-out shorts leg inside the inside-out one, smoothing everything down until the two legs are perfectly aligned, one inside the other.
You’ll see a U-shaped curve that represents the crotch curve from your template. Pin the shorts together along this curve, and sew. Sew again along the bottom of the U using the same stitch–crotch seams get a ton of hard wear, and they’re much easier to sew strongly the first time than to mend later.
Straighten out the shorts, removing one shorts leg from inside the other, and you should easily be able to see the shorts’ waist now. Fold the top edge of the waist down about 1″ to the wrong side of the shorts and sew it to form the waistband, leaving a couple of inches unsewn to insert the elastic.
Take your child’s waist measurement, and measure out a length of 3/4″ or 1/2″ elastic to exactly that length. Pin a safety pin to one end of the elastic, and use that end to thread the elastic through the waistband. When the elastic is completely inserted, overlap the ends, sew them together very strongly, re-insert them into the waistband, and finish sewing closed that last opening in the waistband.
And that’s how to sew two pairs of kids’ shorts from one upcycled T-shirt! Did you miss part one? Check it out right here!