Things You'll Need
Serger or sewing machine
Wooly nylon is a thick, fuzzy thread that covers completely with fewer stitches. Wooly nylon turns a rolled hem into a decorative edging that looks like piping. It makes a simple zigzag stitch into a band of decorative trim. Knit a quick scarf with wooly nylon to create a contrasting rolled hem by simply serging the edge of a square of fabric. Add a band of contrasting "trim" above the ironed-up hem on a printed napkin to quickly create designer napkins.
Thread the upper looper with wooly nylon.
Thread the lower looper with sewing thread.
Thread the left needle with sewing thread, and leave the right needle empty.
Increase the tension on the lower looper. Start by doubling the usual tension setting. Slightly decrease the tension on the upper looper. Start by decreasing it by half the usual setting.
Set the stitch length to 1.5.
Sew a few stitches without fabric to be sure you have threaded the machine properly.
Sew a few test seams to check the machine's settings. Adjust the settings until the seam is flat and the wooly nylon completely covers the edge of the fabric.
Sew along the edge of the fabric to create a rolled hem.
Fill a bobbin with wooly nylon. Insert it into the machine.
Thread the machine with regular sewing thread. Wooly nylon is too thick to fit through the eye of a sewing needle.
Sew a wide zigzag stitch with a short stitch length, on the wrong side of the fabric, along the line where you wish the "trim" to be. This might be 1 inch from a finished edge or along the top of a hem.
Check your owner's manual for instructions on threading and adjusting your serger. Each model is different. You can remove the right needle on the serger to keep it out of the way. You can sew with the blade on the serger up or down. You might need to lower the differential on the serger when sewing with wooly nylon.