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Weft_ Warp _ Weave

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Weft_ Warp _ Weave Powered By Docstoc
					Creative Solutions
by Joi Mahon Dress Forms Design Studio

Weft, Warp & Weave
Understanding the mystery of fabric structure
Part II of III Series on Fiber & Fabric Characteristics

A whole book could be written about fabrics. In fact, many books have been written on specific fibers and fabrics alone. However, getting to technical can be confusing for the average sewer. Let’s narrow down to the nuts and bolts of fabrics and the basic characteristics that affect the home sewer and their fabric selection. In this article we pull back our microscope from the fibers and take a close look at the surface for more clues on what exactly affects fabric performance.
Yarns: Weft & Warp
Fabrics, unless bonded or knits, are woven together using “weft” and “warp” yarns. Remember that “weft” rhymes with “left” meaning they are the yarns that go back and forth, and “warp” are the up and down yarns parallel to the selvedge. These yarns are the structure for any kind of weave or pattern in a fabric. All sewers know the word “grain,” and this is referring to the weft and warp yarns. If a fabric is off grain there are two forms. Skew is when the “weft” yarns are not at a 90° angle to the “warp.” This occurs during processing and is common in printed fabrics before finishing. The second is called Bow and occurs when the “weft” yarns dip or curve in the center of the fabric. This also happens during processing. Off grain weft and warp yarns can directly affect any sewing project. Quilters may not realize that a cotton printed while off grain will not only have an off grain pattern, but this affects the quilt and how it skews when washed. A garment may have the same results. An off grain pattern may look fine at first glance, but when straightening the grain, that design becomes distorted. Consider trying to hem an off grain chiffon gown with a bowed fabric. YIKES! That is every sewers nightmare. While cost does not always reflect quality, there is usually a difference in grain, bow, and thread count between the $2.99 fabric and the $12.99+ version. When making an educated fabric selection take a close look at the yarns and how they are woven.

Weave:
Weaving is done on a loom, and all the weaves done today have been done for thousands of years. While looms have changed, the basics are still the same. Warp yarns are held taut and weft (filling) yarns are inserted to make a cloth. Balance refers to the ratio of warp to weft yarns. A balanced fabric has approximately one warp for every weft or filling yarn. An unbalanced fabric has more of one yarn than another. A typical unbalanced fabric is broadcloth with a count of 144 x 76 and a ratio of 2:1. Balance is important in recognizing and naming fabrics, and in distinguishing the warp and direction of a fabric. Often fabrics take on the name of a weave and this can be confusing to sewers and retail consumers. A bride will ask for a “satin” gown. The bride thinking smooth satiny fabric is actually asking for the satin weave not realizing that she may select silk satin, polyester satin or cotton satin. Another fabric called by the weave is “twill.” Walk into any fabric store and you may run across a section with beautiful “twill suiting” when in reality these nameless fabrics are created with a twill weave. On the other extreme, next time you wear jeans ask someone if they like your “stonewashed twill pants” since denim is a twill weave. You might get a funny look, but denim or jeans is an example of a weave that has taken on a more recognizable name. Sewers frequently ask how to determine the front from the back of a fabric. Understanding these characteristics can help answer those questions.
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Basic Weaves:
The list of weaves is lengthy and educated sewers might find it interesting sometime to look at a book with diagrams of many of the common variations. Whether you know them by name or not, it is important to recognize certain visual characteristics that factor in how the fabric will work for the end use. Here are examples of the top three weaves: • Plain weaves, the most common, are basic over and under patterns and easy to recognize. This weave is best for printed fabrics, accepts finishes well, wrinkles the most, and is the least absorbent. There is no technical front or back of the weave unless printed on. Common fabrics include muslin and quilting cottons. • Twill weave is the second basic weave and is characterized by a diagonal line created by diagonal floats most easily recognized as denim, houndstooth, herringbone, and gabardine. Twill may have a front and back and are rarely printed. There is better wrinkle recovery in twill, and the twill can be right or left handed or at different angles. Twill is typically more expensive due to the higher yarn count. • Satin weave, the third basic weave mentioned earlier, uses tightly woven fibers that use long floats to create a smooth lustrous looking surface. Satin fabric snags easily due to the long floats and tends to unravel more. Common fabrics include satin, sateen and crepe back satin utilizing a crepe yarn. A silk satin is always higher quality than a cotton because of the long silk fiber as cotton has small fibers that will eventually look fuzzy on a cotton satin garment.

Black & white tweed

Fancy Weaves:
Fancy weaves usually create a specific design or characteristic in a fabric due to specialty yarns, extra yarns, creating slack in the tension and other structural factors. Some fancy fabrics include: Dotted Swiss (Swivel-Dot weave), Pique (Pique weave ribs), Jacquard weaves including Damask with satin floats on satin, Brocade with satin floats on plain background, and tapestry with a dominant design on the front, Double Cloth such as velvet which is cut in half, and Seersucker, a warp slack tension weave creating the bubbly effect. Other recognizable fabrics that use ribs in the weave include broadcloth, taffeta, shantung, poplin, and faille. Fabric structure plays an intrical part in how a fabric will perform during sewing and in everyday use. The idea is not to focus so much on the technical, but to understand why/how a weave or grain will affect a project. A tightly woven fabric may need an extra sharp needle to prevent snags, an off-grain quilt may have uneven shrinkage, and an open weave tweed may require interfacing to stabilize the fabric for tailoring. With some basic fiber and fabric knowledge the average sewer can make educated decisions on what fibers and fabrics are best for their next project. Next month we conclude with Part III of this series on Fiber & Fabric Characteristics. We will combine our knowledge of fibers and fabric structure with fabric basics such as count, weight, yarn dyed and printed finishes. &
Joi Mahon is an award winning freelance designer and founder of Dress Forms Design Studio, LLC. Joi works with custom clients offering design, styling and sewing services, as well as offering creative industry services to retailers and manufacturers. Frequently called “The Idea Person,” she is also a founder of J&L Designs, where she owns and licenses a garment patent. Joi is a member of PACC and SEA. For more information, contact Joi at joi@dressformsdesign.com; www.dressformdesign.com; or call the studio at 1-712-239-9921. For more information on Fibers and Fabrics, check out the references and textbook “Textiles” by textile expert Dr. Sara Kadolph who Joi studied under at Iowa State University.

Blue fabric weave

Open weave

White plain weave

Difference Between Warp & Filling:
• Selvedge always runs lengthwise (warp) in fabric. • Most fabric has less elongation (stretch) in the warp. • Warp yarns lay straighter and are more parallel in fabric due to loom tension. • Fancy and specialty yarns are usually in the weft or filling. • Specific fabric characteristics may indicate warp and filling direction. • Warp yarns are smaller and higher in twist to withstand loom tension.
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