What Makes Good Serger Thread

Let's discuss the differences between Spun Poly and Corespun (poly-wrapped poly core) threads. Off the cuff, “Sewing Thread” sounds as vague as saying “kind of” when describing something. There’s a whole lot more to sewing thread, such as different thicknesses (commonly called thread weight), colors, fiber composition, put-up, etc.

Spun polyester and poly-wrapped Poly core (also known as corespun or PP) are the two most common fiber compositions for sewing and serger threads. In this article, we’ll reveal the differences between them as well as the benefits of each fiber composition.

Poly-wrapped poly core threads are made from a combination of two types of polyester yarn, filament polyester and spun polyester. Filament polyester is a long, thin strand of polyester which has undergone an extrusion process and is smooth, strong, and uniform in size. Spun polyester is created from short pieces of polyester called staples, which is twisted and spun together to create a long strand of thread.

To create a poly-wrapped poly core thread, filament polyester is wrapped in a thin layer of spun polyester. The melding of both fiber types creates a spectacular thread for sewing, serging, and quilting. The traits of a poly-wrapped poly core thread are high strength, excellent abrasion resistance, reduced puckering, matte finish, and excellent color appearance. These characteristics combine to create a fantastic thread for craft sewing, general sewing, clothing construction, and quilting.

Whether you are sewing on a home sewing machine or serger, a poly-wrapped poly core thread will provide a smooth stitch with flat seams. Other benefits of sewing with a poly-wrapped Poly core thread are:

• Much stronger than spun polyester threads the same size. A Tex 30 corespun thread is roughly 40% stronger than a Tex 30 spun polyester thread.
• Due to greater strength than spun polyester, a thinner thread may be used to achieve the same quality seam result.
• Seam quality is higher with fewer breaks or restitched seams.

View our corespun polyester threads

For Quilting: OMNI and OMNI-V

For Sewing: Sew Complete

For Serging: Sergin' General

With poly-wrapped poly core threads receiving a lot of praise and attention, this doesn’t mean that spun polyester threads are obsolete. Spun polyester threads have a purpose and are quite popular for mass production of clothing and bedding. Although spun polyester threads don’t share as many high-quality traits as poly-wrapped poly core threads do, there are plenty of applications where spun polyester is a viable choice. Its relative low cost makes it attractive for hobby sewing where a large amount of thread is going to be used.

It is not uncommon for both spun polyester and poly-wrapped poly core threads to be used in the construction of a garment. Denim jeans commonly use spun polyester for overedge seams and poly-wrapped poly core threads for topstitching and seams which experience the most stress.