Piping

Definition and Overview

Piping is a finishing and decorative trim used by wrapping a cord-like core with matching or separate fabric tape and inserting it between two pieces of fabric to be sewn together. A rounded raised edge appears from the seam, clearly defining the outline of a panel seam or edge.

As a material, piping may refer to a product in which the core and covering fabric are preassembled. On the other hand, in sewing specifications, it may also be made for each product using fabric tape and a core cord.

Materials and Structure

The fabric covering the surface may be cotton, polyester, nylon, or similar materials, while the core may use cord made from bundled twisted threads or braided cord. Depending on whether the surface fabric is woven or knitted, and whether the core has a twisted or braided structure, the gloss, stiffness, stretch, and resistance to friction differ.

For straight sections that do not stretch easily, tape cut along the grain can be used, but for curved areas such as necklines and armholes, bias-cut tape is easier to conform to the shape. The combination of the surface fabric thickness and the core thickness also affects how the seam allowance sits.

How to Read Thickness and Width

Piping is generally described by the diameter of the core or the thickness visible on the finished product. However, the basis of the indication may be either the core itself or the visible finished dimension, depending on the product and specification, so confirmation is necessary.

During sewing, not only the visible thickness but also the width of the edge portion used for stitching in is important. If the seam allowance is insufficient, the seam may be too close to the core, causing unevenness on the surface or skipped stitching.

• For curved sections, the thicker the core, the harder it is to follow the shape neatly.
• If the face fabric is thin, check whether the color or unevenness of the core shows through.
• Before mass production, making a sewing sample with the same seam allowance as the actual fabric makes it easier to confirm the finished appearance.

Main Applications

It is used for jacket and shirt panel seams, pocket openings, collar edges, and the edges of cushions and bags. Changing the color scheme creates a design accent, while using a matching color gives the outline a three-dimensional effect.

Its main purpose is to decorate seams, but it also serves to protect edges. However, when the purpose is reinforcement for areas under strong load, the piping alone should not be relied on; the sewing specification and the strength of the base fabric should also be considered.

Selection and Handling Precautions

Select the core thickness, surface material, and stretch according to the thickness of the outer fabric, the application, and the sharpness of the curve. When using it on knit or stretch fabrics, the seam may pucker because the piping itself does not stretch, so confirm the sewing method and the difference in stretch beforehand.

Shrinkage, color fading, and deformation of the core due to washing or dry cleaning vary by material. In particular, check for color transfer in light and dark color combinations, and for fraying at the cut edges or during sewing in woven covering fabrics; if necessary, perform edge finishing or testing.

Piping is not a material that wraps an edge as a flat tape like bias tape; its defining feature is the rounded bulge created by the core. Also, round cord often refers to the cord alone, and its purpose and structure differ from piping, which has a covering fabric and is inserted into a seam.

Frequently Asked Questions

What is the difference between piping and bias tape?

Piping is a specification in which a core cord is wrapped in fabric to create a rounded three-dimensional effect from the seam. Bias tape is generally a flat tape used to wrap a fabric edge or cover a seam allowance. They are similar in that they conform easily to curves, but the finished shape and purpose are different.

What should be noted when inserting piping into curved sections?

In tight curves, thicker piping is more likely to cause puckering or pulling on the inside. It is important to choose a bias-cut covering fabric and sew evenly along the edge of the core while making the necessary notches on the seam allowance side. Check the appearance with basting before final stitching.

Does piping shrink when washed?

The degree of shrinkage varies depending on the fabric covering the surface, the core material, processing, and washing conditions. If the shrinkage difference between the piping and the outer fabric is large, it may lead to waviness or pulling at the seam. If the product will be washed, it is important to conduct a washing test under the same conditions in advance.