Lay out the pattern pieces on your fabric. I chose a print for the body of the briefs and a solid for the fly facing, fly stay and leg bands, so you only see the brief body in this picture. You can pay a good amount for pattern weights or go to the local hardware store like we did and get several 3" washers and use them. The last pattern weights I saw for sale were nothing but washers covered in fabric anyway!
I traced around the pattern since I am using weights. Notice on the pattern that I transferred the marking for the fly stay. This will be an important marking to have.
Fold back the pattern along the fly stay line and mark the fabric on both sides - you can do the back side after cutting out the brief body piece by turning the pattern piece upside down and folding it so the line shows.
Here you can see the line traced onto the fabric. You can use a washable marking device; I used a regular fine point marker since this will be covered and it really doesn't matter if it washes out or not.
Cut out the fly stay, fly facing and leg band, making sure you have the stretch and grain of the fabric going in the right direction.
Here are my three solid color pattern pieces cut out from a coordinating fabric.
A picture of the pattern pieces all cut out.
Leaving a small amount extra on each end, pin the fly facing to the brief body. If you are using a printed fabric or one with an obvious right and wrong side, you want these pieces right sides together. With my fabric, it doesn't matter because ribbing is the same on both sides. Sew to the body with a medium width zigzag stitch or narrow serger stitch. I prefer the regular machine since there is so much regular stitching on these briefs. With my standard Kenmore, the width is 2.5 and the length is 2; with my Janome QC4800 the length and width are both 2.5.
Here are both the fly facings sewn to the brief body.
With the seam facing away from the brief body, fold the rest of the facing over it and then under the seam. Pin in place. You will have leftover fabric overlapping onto the brief body.
Using the same medium zigzag stitch, sew on the top side of the brief close to the seam line. This will leave you with a narrow band of fly facing covering the seam.
Turn the brief over and trim the excess fabric from the fly facing, being careful not to cut through the brief body piece.
Lay the brief body on a table so that the fly pieces overlap and the dart at the top of the briefs matches up. Pin along the fly stay lines from the top of the brief body to the bottom of the fly facing, leaving room for the machine to baste the center piece.
Using a long straight stitch, baste the center pieces together. This will make the next several steps much easier than if it is left un-basted.
Using an iron on the appropriate setting, fold the fly stay in half lengthwise and press it into place. If using fabric with a print, fold the fabric right sides together.
Open up the fabric and, one side at a time, fold the center in to the middle and press it into place, wrong sides together. Don't iron it back and forth or you will stretch the knit out of shape.
A picture of the two pieces of fly stay pressed as directed with folded sides up. It is, in effect, a piece of self-fabric bias tape.
Slide a piece of cardboard between the front and back of the brief body to keep the pieces from being pinned together during the next step.
Carefully pin the fly stay, folds down, along the fly stay line you traced onto the fabric, having the line in the center of the fly stay. Make sure both pieces of brief body fabric are under the fly stay. The bottom edges of the facing will be right at the outer edge of the fly stay.
(Note: at this point you may need to switch to a larger needle to avoid skipped stitches, if you haven't already done so.)
Using your medium width zigzag stitch, sew a seam down both sides of the fly stay, making sure not to catch in the back of the briefs while sewing. Check to make sure that at least one of the seam lines catches in the edges of the fly facing and up to the top of the edge of the fabric above it.
Lay the briefs on your work space with the waist toward you. Folding up the top piece of the overlapping fabric, pin the bottom piece to the back of the brief wrong sides together, matching notches.
Turn the brief over so the back is facing up, placing the part you pinned toward you and the other part of the free flap away from you. Roll the top edge of the brief down toward the pinned edges of the brief.
...Continued in next post...