The first step in sewing your Electron Layette Pants is to select your fabric. Paying attention to stretch, you can use a variety of fabrics including jersey, interlock, ponte, and sweatshirting. For a thorough walk-through, read/watch Choosing Fabric for the Electron Layette.
Cutting the Electron Layette pants is quite simple. You need 1 Front, 1 Back, and 2 Waistbands. Cut the fabric on a single layer and, if your fabric is directional, make sure that your pattern pieces are facing the same direction. Make sure that the direction of greatest stretch is perpendicular to the selvedge so that it stretches most around the body of the baby/pants.
Place the Front and Back right sides together and sew the side seam using a 3/8″ seam allowance. Since your fabric has stretch, you will want to make sure that you are using a stitch that stretches. If you have a fancy stretch stitch on your sewing machine you can use it, but a narrow zig-zag works well too.
If you want, finish the side seam allowance. I went ahead and serged all my seam allowances but it isn’t necessary. Most knits won’t ravel.
Fold the hem of the pants up to the inside 5/8″ and sew it in place. Again, make sure you are using a stretch stitch. We hem the pants before sewing the inside crotch seam because it can be pretty difficult to wrangle such a narrow leg opening through your sewing machine for a traditional hem (sewn after both leg seams are sewn).
Sew the inside crotch seam. Snip the seam allowance close to the seam line. This allows the fabric to relax around the curve when you turn the pants right side out.
If desired, finish the inside crotch seam.
Press the seam allowance of the inner crotch seam toward the back. Tack it in place. You can use either a horizontal (pictured left) or vertical (pictured right) tack.
Place the two waistband pieces right sides together and sew the side seams.
Fold the waistband in half, wrong sides together (right side facing out), lengthwise.
Pin the waistband to the top of the pants, right sides together. Match the side seams and match the center front and center back notches. Then add more pins around, if desired.
Sew the waistband to the top of the pants, leaving a 3″ gap.
This is what the waistband look like after having sewn it on, with the gap visible on the left.
Cut your elastic to length. The pattern gives a general guideline for elastic length, though you will find that elastic varies in its elasticity and baby waists come in different sizes and shapes, so you may want to check elastic length on your own baby for optimal fit.
Put a safety pin through one end of the elastic and use it to thread the elastic through the waistband.
Overlap the two ends of the elastic by 1/2″ and sew the elastic together. I like to go back and forth a couple of time over the overlap to make sure that the elastic is sturdily joined.
Finish the waistband by sewing the gap shut. Make sure that you don’t stitch into the elastic.
If desired, finish the seam allowance. If you are serging your seam allowance, make very sure that you don’t cut or stitch into the elastic channel. It can be a little fussy because the presser foot will be lifted up by the bulk of the elastic.
Your pants are finished!