Cathy's Woolly Nylon Serging Tips

In junior high, Cathy C. had to take home economics. Half the year was dedicated to cooking, while the other half was dedicated to sewing. That was where she began making her own clothes, and she hasn't stopped since.

By 1987, her mother had purchased an Elna Lock L4 serger. They enrolled in classes together at the dealer, learned the stitch types side by side, and before long, the machine was spending more time at Cathy's house than at her mother's. "So she bought a serger for me. It was a different model, and I could see that my mother's machine, the L4, was better. It didn't take me long to trade up so I could use the same model."

That was over 30 years ago. Since then, Cathy has made everything from formal dresses to a squirrel costume for a parks-and-recreation mascot. She's the costume designer for school plays. She makes her own clothes year after year because nothing in stores fits her the way she wants it to. Every Christmas, she sits at her serger and makes pajamas for her great-nieces and nephews, about 18 pairs.

What Textured Thread Does (and When It Matters)

If you've ever serged a rolled hem or an edge finish and noticed the fabric peeking through between the stitches, you already understand the problem that textured nylon thread addresses.

Most standard serger threads are made from spun polyester, an economically priced, common all-purpose thread. It lies flat against the fabric, and the looper stitches are set with visible gaps between them (look at the bottom or sleeves of a T-shirt to see this stitch pattern). On dark fabric with light thread (or vice versa), these gaps stand out. The edges almost look striped rather than fully covered and finished.

Woolly Nylon differs significantly from spun polyester. It is not spun or twisted; instead, it is a texturized nylon, meaning each strand has a crimped, spongy structure that compresses under the tension of your machine and then springs back once stitched in place. This expansion is essential. Where smooth thread leaves gaps, textured thread fills them, creating a denser, softer edge that conceals the fabric underneath.

The difference goes beyond looks. Since the thread has great stretch and recovery, it moves with the fabric instead of resisting it. This is key for knits, swimwear, activewear, and anything with stretch. A rolled hem on a chiffon dress needs thread that won't pull or pucker the delicate fabric. A serged edge on a baby towel must stay soft after many washes, which is why Woolly Nylon is the best looper thread for both cases.

Cathy first noticed the difference during her initial serger class, the same one she took with her mother. "The samples for decorative edging using Pearl Cotton and Woolly Nylon showed that these threads could create a striking look at the edge of the fabric." That was the moment it clicked: not every project needs textured thread, but the ones that do stand out more with it.

Baby Towels, Formal Dresses, and Knowing the Difference

Cathy makes many hooded baby towels and washcloths and appreciates how Woolly Nylon creates an attractive, secure hem. Terry cloth is thick and absorbent. When you finish the edge with standard thread, the fabric can be seen between the stitches and may pile. With Woolly Nylon in the lower looper, the edge completely wraps the terry, and the finished towel feels soft rather than scratchy against a baby's skin.

"It also makes all the difference when hemming sheer fabrics on formal dresses using a rolled hem setting," she said. On sheer fabrics, a rolled hem with regular thread can look sparse, with looper stitches spaced out and fabric visible through each gap. Textured thread fills those gaps, making the hem appear like a tiny, tightly wrapped cord along the edge. She also uses it to edge cuffs and collars on clothing, wherever she wants the thread to cover the fabric edge rather than just holding it.

Two Machines, Two Jobs

When Cathy's Janome didn't produce the wide over-edge stitch she wanted for the baby towels, she didn't lower her expectations. She did what most of us do when we encounter this situation: she bought another machine, an Elna Lock! "It is my go-to for baby towels. I use the Janome for other projects." The Elna produces the wider stitch she needs for terry cloth. The Janome handles clothing and general serging. No switching setups back and forth.

For the baby towels, her threading is specific: "Pearl Cotton goes in the upper looper, Woolly Nylon in the lower looper, and general serger thread in the left-hand needle using three-thread overlock."

Use your imagination to picture what this looks like. The Pearl Cotton, which is decorative and visible, wraps over the edge. Underneath, the Woolly Nylon presses against the fabric and the baby's skin, soft and fully covering the raw terry cloth. Spun polyester thread in the needle holds the stitch structure together without adding bulk. Three threads, three jobs, all working together to create a secure, soft, and durable edge.

If you haven't had much opportunity to sew on an overlocker or serger, it's important to understand that Woolly Nylon is a looper thread, not a needle thread. You can place it in the upper looper, the lower looper, or both, depending on how much coverage you want and where you want it. The upper looper only provides coverage on the visible side. Both loopers give a fully wrapped appearance on each side, although this slightly increases bulk. Therefore, using both loopers is better suited for decorative edging than for garment seams, where you want items to lie flat.

Color, Up Close

Imagine picking up one of Cathy's baby towels. The top edge features a variegated Pearl Cotton, shifting between soft pastel shades every few inches. Flip the towel over, and the underside of that same edge is a single coordinating color of Woolly Nylon, clean and uniform, with no terry cloth fibers poking through. The contrast between the multicolored top and the solid bottom contributes to her towels' finished, intentional look.

Her approach varies depending on the project. "For hemming, it needs to match. When using Woolly Nylon for edging on items, it depends on the desired look: sometimes matching, but often intentionally using contrasting colors to add variation to the finished design." On a formal dress, the matching thread disappears into the hem. On a decorative jacket collar, a contrasting color turns the edge into a design detail.

She buys four cones at a time, enough to keep both sergers threaded and have backups ready. The more you sew with Woolly Nylon, the easier it becomes and the more projects you discover for using it.

If Your Serger Is Collecting Dust

You're not alone. Many sewists own a serger but feel intimidated by it or unsure how to use it effectively. This is a common experience. Cathy's advice is practical: "The more you use it, the easier it should become. I've purchased all my sewing machines from a dealer, so I've always been offered lessons and ongoing help with issues."

And the machines themselves have become easier to use. "The newer machines are so automated, if you pick a stitch type, the machine sets the tensions automatically," Cathy said. "That's so much easier than the first Elna Lock I used. You had to adjust the knobs for each different stitch type." If you're starting today, the learning curve is shorter than it was in 1987.

A Towel Waiting for a Name

When Joann's closed in Cathy's area, she bought bolts of pastel terry cloth. "I'm grateful to have about 15 baby towels set aside." One of those towels is different from the others. "My second granddaughter will be arriving this May, and a towel for her is ready except for embroidering her name on the hood."

This is the highlight of Cathy's sewing journey: the joy of creating something, whether as simple as a terry cloth towel or as intricate as a formal dress, and most importantly, for the person she's making it for. She loves making gifts and items for others more than anything.

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