Stretch Stitching

Definition and Overview

Stretch stitching is a method of sewing together stretch materials and fabric with a difference in length between them. During sewing, the elastic is stretched, and when the tension is released after sewing, the fabric gathers due to the elastic’s recovery force, creating dimensional gathers and a close fit to the body.

“Stretch stitching” does not refer to the type of elastic or the fabric weave; it refers to the sewing operation and specification. It is distinguished from elastic threading, where the elastic itself is not stretched while being inserted, and from knit sewing, where only the fabric is stretched while sewing.

Materials and Structure Used

In general, elastic webbing, corded elastic, and shirring elastic are used. Elastic materials include those in which elastic yarn or stretch yarn is used as the core and covered with fibers, as well as those whose outer layer is formed by weaving, knitting, or braiding. Depending on the structure, thickness, feel against the skin, degree of stretch, and tendency of the edges to fray differ.

The materials being sewn to include woven fabrics, knits, nonwovens, and others. However, if strong elastic is attached to a woven fabric with low stretch, shrinkage is more likely to stand out, and if a stitch with little stretch is used on a highly stretchable knit, thread breakage or seam puckering may occur when worn.

How to Specify Width and Stretch

The width of the elastic affects the finished appearance, the required holding force, and how easy it is to take seam allowance. Narrow elastic makes it easier to create fine gathers, while wider elastic can support the area more evenly, but the attached section may feel stiff.

The amount of stretch is controlled by the relationship between the stretched length of the elastic and the length of the fabric to be sewn. In specifications, indicating not only the finished dimensions but also the cut length of the elastic, the sewing section, notches for even distribution, and the finished sewn state can help prevent misunderstandings.

• Even with the same elastic, the stretch length changes depending on the pulling force.
• The amount of stretch may be changed by section, and the entire circumference may not be treated under the same conditions.
• In prototypes, check not only the flat state but also the fit and return behavior when worn.

Main Uses and Sewing Precautions

It is used for areas that require both gathers and fit, such as the waist, cuffs, hems, necklines, and edges of underwear and sportswear. There are specifications in which the elastic is sewn to the seam allowance and turned over, and others in which it is shown on the front side as part of the design.

In sewing, it is important to make notches in both the fabric and the elastic and stretch them evenly by section. Pulling too strongly at once causes uneven gathers and can lead to seam puckering or twisting of the elastic. Also check the feed amount of the fabric by the feed dog and presser foot, and adjust differential feed as needed.

Recovery Properties and Handling

The finished result is greatly affected by the elastic’s tendency to return to its original state after being stretched. Conditions such as remaining stretch, slow recovery, or localized narrowing may be related to the choice of elastic, excessive stretching, or heat and needle damage during sewing.

High temperatures during washing or drying, long-term storage, and contact with sweat or chemicals can reduce the elasticity of the elastic. Before mass production, confirm that the amount of gather, fit, and seam condition are maintained after the intended washing conditions.

Frequently Asked Questions