I first shared this idea last year when I made a couple pair for my older two boys. But my youngest recently decided to potty train (insert happy dance here) and is now in underwear full time. So it was time to make a few for him.
After making quite a few of these, I’ve come up with some better ways of doing things than when I originally shared a year ago. I decided to do an updated tutorial, showing those changes. I’ve also updated the pattern with a longer rise. My shared pattern fits a size 3/4 . To fit my skinny 2 year old, I just took my own pattern in a little. When I make them for my older son, I just increased the size to fit him. Or, if you’d prefer, you can always use the upcycling idea of t-shirt to briefs with your favorite multi-size commercial pattern, like Fishsticks Designs’ Undercover Bottoms (and matching tank!).
-You want a stretch, knit, or ball point needle. A regular needle is too sharp and will tear your fabric.
-If you have a walking foot, I highly recommend using it. It makes a huge difference. If you don’t have a walking foot, you can still get the job done, the walking foot just makes it so much nicer.
-If you have it, use a stretch stitch. Mine looks like this
CUTTING THE PIECES:
You’ll need a t-shirt with a fun graphic or print, some 1-inch braided elastic, and your pattern. You can download my pattern here.
A good rule, I’ve found, for how big of a shirt you’ll need is at least a size larger than the size brief you’re making; i.e.: for child size 3/4 briefs, use at least a child size 5 shirt.
Begin by cutting your shirt up one side, like so
When you lay out your pieces on the shirts, line things up so that you cut out the graphics you want to keep, and leave out, or keep to the seam allowance, those you don’t
You also want to salvage the hems of the shirt.
Cut just below the outer-most stitch lines, keeping it in long strips. This will later become your binding.
If the shirt has a ribbed knit somewhere, I prefer to use that as it adds a nice contrast.
Set the cut hems aside, you’ll need them in a few steps.
PREPPING YOUR PIECES:
The first thing I do is mark each of the leg pieces so that I know which side is the back. I just put a little “B” in pencil on the wrong side of the fabric at the back edge
Now grab the edge pieces you cut off. See how they form little premade bias tape? Handy, no?
Open the binding
And sandwich the raw edges of the bottom of both legs and the curved cutout of both center front pieces, if making a fly.
So you should have both legs bound along their bottom edges and both front center pieces bound at the fly
Stitch the binding in place
And then I like to do a second row of stitches for fun
If you want, you can still make the look of a fly even if you opted for the no-fly version, really easily. Just take some of the binding you cut. Keep it folded in half. With the folded edge towards the inside of the curve, pin the binding down from about 1/2 inch of the top of the front center, forming a cute little fake fly
And double stitch in place. See, faux fly. Not functional, but personally, I would rather my children not know the real purpose of the weird little pocket in their underpants until they’ve perfected their technique and aim a little more. My two year old has not yet reached this milestone. Fake fly for him.
If you’re doing a fly, lay your fly pieces on top of each other, both with right sides facing up. If you’re not doing a fly, you just have the one piece. From here on out, you’ll be treating the stacked fly pieces as one piece. If you want, you can do a basting stitch at the bottom and top of the staked fly pieces, to keep them in place while sewing. I don’t find this necessary, but then I’m pretty good. And lazy. Okay, just lazy.
With your front center laying right side up, lay the back center piece, right side down, on top of it. Match the lower, short side of the back center with the lower, short side of the front center
Stitch in place
Open and press seam
When making these, I like to do a double top stitch down either side of all the seams. It adds durability, keeps the seam allowance in place, and looks nice
Take your leg pieces
And fold them right sides together, matching raw edges of the short sides
Sew the length of the short side
Open and press the seam
Top stitch on either side
PUTTING IT ALL TOGETHER:
With the center piece laid flat, right side up, lay one leg, turned right side out, so that the top of the back center is flush with the top of the back leg. Refer to the markings you made when cutting the leg pieces to make sure you have the back part of the leg lined up with the back of the center piece.
And work your way around, bringing the rest of the leg up to be flush with the crotch area, then the center front, until the entire leg is pinned to one side of the center piece, right sides together
Sew, press open seam, double top stitch
Turn the leg right side out
Attach second leg exactly the same way on the other side of the center piece.
Measure the waist of the briefs and cut a piece of elastic of the same measurement.
Overlap the elastic at the ends about one inch
Using a zig-zag stitch, secure the raw edges of the elastic, forming a circle
Place the elastic around the outside of the right side of the briefs at the waist, about 1/2 inch down. Both the elastic and the briefs should be right side out. Pinning would probably be a good idea.
Now you’re going to stitch the elastic in place. Using the same stretch stitch as before, pull the elastic and the briefs taught with one hand, while feeding through the machine with the other
Double stitch to secure
And you’re done!
And hurray for all three of mine wearing underwear!