Monday, March 1, 2010

Textiles review: natural protein fibers

This is part three of my textiles review, in which we go over the natural protein fibers.

Natural protein fibers come from animals. Wools are the hair and fur of animals, and silk is secreted by silkworms. The protein in wools is keratin, and the protein in silk is fibroin. While the word “wool” technically refers to any hair fiber from any animal, it is commonly understood to refer only to sheep hair. Specialty wools (fibers from other animals) are usually referred to by the animal’s name, and they cost more than sheep wool.

All natural protein fibers share certain properties because of their common chemical composition. These properties are:

Resiliency: Protein fibers are resilient. They resist wrinkling, and wrinkles may disappear between uses. Wool is more resilient than silk.

Hygroscopic: Protein fibers are highly absorbent. They shed water slowly, so they retain their insulation properties and remain dry to the touch while wet.

Weaker when wet: Protein fibers have lower tenacity when wet. Silk loses about 15% strength when wet, and wool loses about 40%.

Specific gravity: Protein fibers have a lower specific gravity than cellulosic fibers.

Harmed by alkalis, oxidizing agents, and dry heat: Detergents, bleaches, and sweat damage the fibers. Steam should be use when ironing. Most protein fiber garments require dry-cleaning.

Flame resistant: Protein fibers do not ignite easily and will self-extinguish. They emit a burnt-hair smell and leave behind a black, powdery ash.

Wool
This section is about sheep wool. Specialty wools will be covered later.
Wool is a staple fiber from sheep’s hair. Wool is produced primarily in Australia, New Zealand, China, and Eastern Europe. The U.S. produces less than 1% of the world’s wool.

Wool production
Sheep are sheared once per year, usually in the spring. A newly removed fleece (raw or grease wool) contains 30% to 70% by weight of impurities such as dirt, grease, and sweat. The fleece is cleaned to produce scoured wool. The fleece is graded to evaluate it for fineness and length, then sorted to separate the sections of different qualities. Wool fibers are laid parallel to one another and twisted together to make yarns. Felt is made by pressing wool fibers together without twisting them into yarns.

Physical structure of wool
Length: Long, fine wool fibers, with an average length of 2½ inches, are used for worsted yarns. Short, coarse fibers, with an average length of 1½ inches, are used for woolen yarns.

Longitudinal view: Wool is a naturally crimped fiber. The fiber twists and bends back and forth around its axis giving it spring like qualities. The crimp accounts for wool’s excellent resiliency, flexibility, elongation, and elastic recovery.

Cross-sectional view: Wool fibers have diameters ranging from 10 to 50 micrometers. The fibers are round. The cuticle, the outer layer of the fiber, contains a dense layer of scales. These scales make the fibers water repellent, and allow felting. The cortex is the main part of the fiber. The cells on either side of the cortex react differently to moisture and temperature, giving wool its crimp. The center of the wool fiber is the medulla, a microscopic honeycomb-like structure containing air spaces. These air spaces add to wool’s thermal retention. Most worsted fibers do not contain medullas.

Properties of wool:
Aesthetics: Wool varies in color from white to dark brown. It accepts and holds dyes well. Woolen wool has a matte appearance; worsted wool may be more lustrous. Texture and drape are determined by yarn and fabric structure and by finish.

Durability: Wool fabrics are durable. Wool has a low tenacity (1.5 g/d), but its excellent elongation and elastic recovery allow it to resist damage. Wool’s wet tenacity is 1.0 g/d.

Comfort: Wool is highly hygroscopic – it is highly absorbent and it releases moisture slowly. Wool absorbs small droplets of moisture such as sweat while repelling larger droplets such as rain. Wool is a poor conductor of heat which makes it an excellent insulator. Wool continues to provide insulation while wet. Wool may induce an allergic reaction in some people.

Appearance retention: Wool is a highly resilient and elastic fiber. It resists wrinkling, and recovers its shape. If properly cared for wool has good dimensional stability, but if improperly washed it will shrink, felt, and tear. Wool should be dry-cleaned. Wool does not soil or stain readily, and with proper cleaning techniques stains can be removed.

Care: I can’t say this enough: WOOL IS DRY-CLEAN ONLY! Wool is damaged by alkalis (most detergents) and chlorine bleach. Moths eat wool; store your wool carefully. Wool is slow to ignite and it self-extinguishes, but there is still no good reason for you to set your wool clothes on fire.

Specialty wools

Mohair comes from the Angora goat. It is a smooth, silky, fine fiber without crimp. Most fibers do not have a medulla. Mohair is highly resilient.

Cashmere is from the Cashmere goat. The fibers have very fine scales and no medullas. It is used to make fabrics with a warm, soft, buttery hand, lustrous appearance, and excellent draping characteristics. It is expensive.

Llama and Alpaca wools come from South American cousins of the camel. Alpaca fiber’s soft hand, good luster, and excellent draping characteristics make it good for apparel. Llama fiber is coarser than alpaca fiber. It is often used for coats and suitings.

Camel’s hair is from the two-humped beasties (Bactrian camels). The hair is shed naturally; camels do not need to be shorn. The fiber provides great insulation without weight. It is usually used in coats, scarves, and suits. It is a tan fiber that is usually used undyed.

Angora is from the Angora rabbit. It is a long, fine, fluffy, soft, and slippery fiber. The fiber does not dye well. It is difficult to spin into yarns because it is so sleek, so it is often blended with other wools. Lambs are cute, but the Angora rabbit is the most adorable wool critter.

Silk
Silk is the only natural filament fiber. Silk was first used as a fiber in Chine more than 4,000 years ago. It is excreted by the silkworm to spin its cocoon in an attempt to metamorphose into a moth.

Silk production
Sericulture is the production of cultivated silk. Silk moths lay eggs on specially prepared paper. After the larvae hatch they are fed mulberry leaves. After roughly five weeks the caterpillars begin to spin their cocoons. Cocoons are made from a single strand of silk, approximately one mile long. The strands of silk are coated with a gum, called sericin. After the cocoon is finished, the pupa is killed with heat. The cocoons are unwound to produce fibers, the sericin is removed, and the fibers are wound together to produce yarn.

Wild silk is produced by collecting empty chrysalises from wild silkworms. The adult moth tears through the fiber as it exits the cocoon, so wild silk is a staple fiber. The sericin is not removed from wild silks.

Physical structure of silk
Silk is a smooth, thin fiber. The diameter of silk fiber is approximately 11 micrometers. It is a solid fiber with a triangular cross shape. Slight striations may be present along the length of the fiber. Wild silk tends to be coarser than cultivated silk.

Properties of silk
Aesthetics: Silk is a luxury fiber. It has a soft luster with an occasional sparkle. It wrinkles more easily than wool, but it is more resilient than cotton. Its color, hand, and drape vary. Wild silks have duller luster and more texture than cultivated silks.

Durability: Silk is one of the strongest natural fibers with a dry tenacity of 4.5 g/d. It loses up to 20% strength when wet. Silk has medium elasticity; at 2% elongation it returns to only 90% of its original length. Silk is damaged by sweat, body oils, chlorine bleach, sunlight, mineral acids, metallic salts (deodorants), and carpet beetles. It is resistant to hydrogen peroxide.

Comfort: Silk is a poor conductor of heat, so it can provide insulation. Light weight silk fabrics are comfortable in warm weather. It has good absorbency, and it is hygroscopic. Silk may develop a static charge. Silk has a soft, smooth, silky hand.

Appearance retention: Silk has moderate resistance to wrinkling. With its low elasticity, if it gets stretched it will stay stretched. Silk has moderate abrasion resistance, but with its typical uses it is rarely subjected to harsh abrasions. Staple silk may pill.

Care: Silk should by dry-cleaned. Silk may be pressed at moderate heat (300oF) with a damp press cloth. Silk is flame retardant and self extinguishing, but you should still keep it away from open flames.

Types of silk
Tussah is the most common type of wild silk

Noil silk (waste silk) is a staple fiber made from the broken pieces and cocoon remnants of cultivated silk.

Duppioni silk is made if two silkworms spin their cocoons together. It is not possible to fully separate the fibers. The yarns have a thick-and-thin appearance. It is used to make shantung.

Spider silk is not currently commercially produced, but several researchers are attempting to develop cost effective ways to produce it. The protein in spider silk is spidroin. Spider silk has excellent tenacity and elasticity. Efforts have been made to collect the silk directly from spiders and to genetically enhance silkworms and goats to produce it. A piece of spider silk fabric is currently on display at the American Museum of Natural History in New York.

Sunday, February 28, 2010

Textiles review: natural cellulosic fibers

This is part two of my textiles review in preparation for my upcoming test.

Plants contain cellulosic fibrous bundles in their roots, stems, leaves, and seed casings. These fibers may be easily removed from some plants to be used as textile fibers. Fibers are classified according to the part of the plant from which they are removed. Seed fibers grow in the seedpod of plants, bast fibers are from a plant’s roots or stems, and leaf fibers are obtained from leaves.

Examples of seed fibers are cotton, kapok, coir, and milkweed.

Examples of bast fibers are flax, ramie, hemp, and jute.

Examples of leaf fibers are piña, abaca, sisal, and henequen.

While there are great differences between various natural cellulosic fibers, there are some properties they all share because of their similar chemical make-up. Properties common to natural cellulosic fibers are:

Good absorbency – cellulose can take up a lot of moisture. Natural cellulosic fibers are good for summer wear, towels, diapers, and active sportswear.

Good conductor of heat (poor thermal retention) – Natural cellulosic fibers are bad insulators. Apparel made from these fabrics does not trap heat. It is a cool fabric suitable for use in warm environments.

Able to withstand high temperature – Natural cellulosic fibers can be washed and ironed at high temperatures. They may be boiled or autoclaved for sterilization.

Low resiliency – Fabrics wrinkle badly.

Poor loft – Fibers can form dense, high count yarns and fabrics. They may be used to make wind resistant fabrics.

Good electrical conductor – Fabrics do not build up a static charge.

Heavy fibers – Fiber density is approximately 1.5 g/cc. Natural cellulosic fibers are heavier than natural protein fibers and most manufactured fibers.

Damaged by mineral acids – Try to avoid acid stains. If you can’t avoid them, clean them quickly.

Resistant to alkalis – Fabrics may be washed with regular detergents.

Damaged by mildew, crickets, and silverfish – Store items in dry conditions.

Resistant to moths – Moths will not eat cellulosic fibers, but you still do not want moths living in your closet.

Inflammable – Fibers ignite quickly and continue to burn after being removed from the ignition source. Burnt fibers smell like burnt wood and leave behind a white or light grey powdery ash.

Poor to moderate sunlight resistance – The fibers are suitable for outdoor apparel, but window treatments should be lined to prevent too much exposure to sunlight.

Cotton
Cotton is the most commonly used natural cellulosic fiber. Cotton fibers grow from the seeds in the boll (seedpod). Each boll contains seven or eight seeds, and each seed may have up to 20,000 fibers growing from it.

Cotton production
Ripe bolls are picked by machines. They are sent to a gin where the seeds are separated from the fibers. The fibers, called lint, are packed into bales and sent to spinning mills. Each bale weighs 480 pounds. The spinning mills make yarns.

Physical structure of cotton:
Color: Most cotton fibers are a creamy white or light tan, but some naturally colored cottons are available. Colored cottons produce less per acre than white cotton, but they sell for about twice as much. Brown, red, beige, and green are available. Unlike most dyed fabrics, colored cottons become darker with age and care. Cotton fibers take up dyes well.

Length: Cotton is a staple fiber. The fibers range in length from ½ to 2½ inches depending on the genetic variety of the plant. Long staple cottons, which are greater than 1 5/16 inch are finer and make stronger, higher quality yarns. They cost a lot more too. Sea Island, Egyptian, Pima, and Supima are types of long staple cottons. Upland cottons, the most commonly grown cottons in the U.S., are medium length cottons (7/8 to 1¼ inch). Short-stable cottons (less than ¾ inch) are produced primarily in Asia.

Cross-sectional view: Cotton fibers are 16 to 20 micrometers in diameter. The fiber has a thin primary cell wall surrounding a thicker secondary cell wall. The center of the fiber is the lumen, the central canal through which nutrients travel as the fiber grows. Immature fibers are U shaped, and mature fibers are kidney shaped.

Longitudinal view: Cotton fibers have a ribbon-like twist called convolutions. The convolutions allow the fibers to cling together which makes yarn spinning easy.

Properties of cotton:
Aesthetics: Cotton has a matte appearance and low luster. Cotton can be made slightly lustrous through mercerization, i.e. treating it with NaOH which causes the fibers to swell. The drape and texture is affected by the yarn size, fabric structure, and finish. Cotton wrinkles easily.

Durability: Cotton is a medium-strength fiber, with a dry breaking tenacity of 3.5 to 4.0 grams per denier. It is 30% stronger when wet. Cotton has good abrasion resistance, low elongation (3%), and moderate elasticity.

Comfort: Cotton’s good heat conductivity, good electrical conductivity, high absorbency, and soft hand make it a very comfortable apparel fabric, particularly for use in warm environments.

Appearance retention: Cotton has moderate appearance retention. Its low resiliency allows it to wrinkle easily, but wrinkles may be pressed out. Cotton will shrink unless it is given a durable-press or wrinkle-resistant finish. Cotton has moderate elastic recovery; it recovers 75% from 2% to 5% stretch. Stretched cotton garments stay stretched.

Care: Cotton soils and stains easily. Cotton withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Cotton may be ironed at high temperatures. Cotton should be stored in dry conditions to prevent damage from mildew.

Other seed fibers
Coir is from the fibrous mass between the outer shell and husk of coconuts. It is a stiff fiber. It is usually used to make highly durable indoor and outdoor mats, rugs, and tiles.

Kapok fiber is from the seed of the Java or Indian kapok tree. The fiber is soft, lightweight, and hollow. It breaks down easily and it is difficult to spin into yarns. It is used as fiberfill and as the stuffing for pillows. It used to be used as a stuffing for lifejackets and the mattresses on cruise ships because it is very buoyant.

Milkweed has properties similar to those of kapok.

Flax
Flax is one of the oldest textile fibers, but its use has declined since the invention of power spinning for cotton. Flax fabric is linen, although the word linen is now often used to refer to table, bed, and bath fabrics made from other materials. Flax is a bast fiber.

Production of flax
Flax fibers are from the stems and roots of the flax plant. The plant is cut or pulled out of the ground to keep the fibers as long as possible. The fibers are found just under the bark or outer covering of the plant. They are sealed together by pectins, gums, and waxes. There are four steps to obtain fibers from the plant:

Rippling – the plant is pulled through a machine to remove the seeds.

Retting – bacteria break down the pectin that binds the fibers together.

Scutching – the stalks are passed through rollers to crush and remove the outer covering so the fibers may be removed.

Hackling – the fibers are combed to separate them into individual strands.

Physical structure of flax
Length: Flax is a staple fiber. Flax fibers range in length from 2 to 36 inches. Short fibers are called tow; long fibers are called line.

Cross-sectional view: Flax fibers are 12 to 16 micrometers in diameter. They have a polygonal shape. There is a small central canal similar to cotton’s lumen.

Longitudinal view: Flax fibers are straight. There are crosswise markings, called nodes, along the length of the fiber.

Properties of flax
Aesthetics: Flax has a high luster that can be further increased with finishes. Flax has a stiffer drape and harsher hand than cotton. Flax takes up dyes well.

Durability: Flax is strong for a natural fiber. Its dry tenacity is 3.5 to 5.0 g/d, and its wet tenacity is 6.0 g/d. Flax has very low elongation (7%) and poor elasticity (65% recovery at 2% elongation). Flax has good flat abrasion resistance, but poor flex abrasion resistance. Repeatedly folding a piece of linen in the same place will cause the fibers to break.

Comfort: Flax is a good fabric for summer apparel. Its high absorbency (better than cotton), wicking properties, and poor thermal retention make it very comfortable in warm weather. It will not build up a static charge.

Appearance retention: Flax has poor appearance retention. It wrinkles very easily and does not recover from being stretched.

Care: Flax withstands high heat, it is stronger when wet, and it is resistant to alkalis, so it may be machine washed with hot water and normal detergent. Flax may be ironed at high temperatures, and it will require pressing often. Flax should be stored in dry conditions to prevent damage from mildew.

Other bast fibers
Ramie: Ramie fibers are 4 to 6 inches long. The fibers are whiter and softer than flax. Ramie does not retain dyes well unless it is dry-cleaned. Ramie is strong for a natural fiber, but it lacks resiliency, elasticity, and elongation potential. It is resistant to mildew, insects, and shrinkage. It is used for apparel, window treatments, ropes, paper, and table and bed linens.

Hemp: Hemp is similar to flax. The fibers range in length from 3 to 15 feet. Hemp production is illegal in the U.S. Hemp has a low environmental impact; it does not require pesticides. It produces 250% more fiber than cotton and 600% more fiber than flax on the same amount of land. Hemp plants can be used to extract zinc and mercury pollutants from soil. Hemp is used for ropes, apparel, and paper. Potheads are willing to pay inflated prices for hemp apparel because it is related to the marijuana plant.

Jute: Jute is one of the cheapest textile fibers, and one of the weakest cellulosic fibers. Jute has poor elasticity, elongation, sunlight resistance, mildew resistance, and colorfastness. It is used to produce sugar and coffee bagging, carpet backing, rope, and wall coverings. Burlap is made from jute.


Leaf fibers
Piña fibers are from the leaves of the pineapple plant. It is used to make lightweight, sheer, stiff fabrics for apparel, bags, and table linens. It is also used to make mats.

Abaca is from a member of the banana tree family. The fibers are coarse and very long (up to 15 feet). It is a strong, durable, and flexible fiber used for ropes, floor mats, table linens, apparel, and wicker furniture.

Sisal and henequen are similar plants. The fibers can be used to make strong ropes, but they are damaged to salt water so they are not suitable for maritime ropes. The fibers are used for upholstery, carpets, and wall coverings.

Saturday, February 27, 2010

Textiles review: fiber properties & serviceability concepts

The first test of the semester in my textiles class is rapidly approaching. I have attended every lecture and lab, done all my homework, taken meticulous notes, and kept up with all the readings, and still I am worried. There is a lot I need to know. The professor gave us a study guide for the test, but she could have conveyed the same information by simply saying, “Memorize chapters one through seven.” I decided to summarize the important concepts in a blog entry. I expect doing so will help me retain this information, and perhaps some of you will find it useful and interesting too.

Chapter 1 – Introduction to textiles

Fiber – any substance with a high length to width ratio and suitable characteristics for being processed into a fabric. Fibers are the smallest components of a fabric.

Yarn – an assemblage of fibers twisted or laid together to make a continuous strand.

Fabric – a flexible planar substance constructed from solutions, fibers, yarns, or fabrics, in any combination.

Gray (grey, greige) goods – an unfinished fabric.

Finish – any process used to add color and enhance performance of gray goods.

Textile (textbook definition) – this term originally meant woven fabrics, but it is now used to refer to fibers and anything made out of fibers.

Textile (lecture definition) – fiber + yarn + structure + finish = textile. Gray goods are unfinished. Felt is made without yarn.

Chapter 2 – Serviceability concepts
Serviceability is a measure of a textile product’s ability to meet the specific needs of a customer. There are eight serviceability concepts used to describe a textile’s performance. These concepts do not describe a textile as good or bad, rather they allow a customer to understand how a textile will perform in specific situations. A textile that may be great in one environment may be terrible in another. For example, wool has excellent thermal retention, so a wool sweater that is comfortable in winter is uncomfortable in summer.

The eight serviceability concepts are aesthetics, durability, comfort, safety, appearance retention, care, environmental impact, and cost. The terms in italics after the definitions are fiber properties that relate to each concept. The properties will be defined in the next section.

Aesthetics – attractiveness/appearance of a textile. How it looks. Luster, drape, texture, hand, dyeability

Durability – the manner in which a textile withstands use. The length of time a product remains usable for the purpose for which it was intended. Abrasion resistance, flexibility, tenacity, elongation, sunlight resistance, moth resistance, mildew resistance

Comfort – the way a textile affects heat, air, and moisture transfer. How it feels to the body. Absorbency, heat conductivity, density, electrical conductivity, wicking

Safety – a textile’s ability to protect a body from harm. Tenacity, absorbency, heat conductivity, heat sensitivity, flammability

Appearance retention – how the product maintains its original appearance. Resiliency, dimensional stability, shrinkage resistance, elasticity, loft, sunlight resistance, pilling

Care – the treatment required to maintain a textile product’s original appearance and cleanliness. Moth resistance, heat resistance, mildew resistance, chemical reactivity, shrinkage resistance

Environmental impact – effects of production, use, care, and disposal of a textile product.

Cost – amount paid to acquire, use, maintain, and dispose of a textile product.

Chapter 3 – fibers and fiber properties
Fibers may be classed as natural or manufactured. Natural fibers grow in nature in recognizable fiber form. They come directly from plants (cellulosic fibers) or animals (protein fibers). Manufactured fibers are formed into fibers from chemical compounds. They do not exist in fiber form without human intervention. Manufactured fibers may be regenerated or synthetic. Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Regenerated fibers are made from cellulose (plant) or protein (plant or animal). Synthetic fibers are made from polymers that do not occur naturally. Most synthetic fibers are made from petrochemicals.

The properties of a fiber, yarn properties, fabric construction, and finish contribute to the properties of a fabric. The physical structure, chemical composition, and molecular arrangement of a fiber determine its serviceability properties.

Length is the measurement of the length of a fiber used to make yarns. Staple fibers are short fibers measured in inches or centimeters. Staple fibers range in length from less than one inch to approximately 18 inches. Except for silk, all natural fibers are available only as staple fibers. Filament fibers are long, continuous fibers measured in miles or kilometers. Silk and manufactured fibers may be either staple or filament.

A fiber’s diameter is measured in micrometers. Natural fibers are subject to growth irregularities that affect their diameter. The diameter of manufactured fibers is controlled during production.

Denier is the weight in grams of 9,000 meters of a fiber or yarn.

Fibers may be solid or hollow. Their surfaces may be smooth or textured. The cross sectional shape and surface contour of natural fibers is a result of how the fibers grow. The shape and surface contour of manufactured fibers is controlled during production.

Crimp is twists, curls, or coils along the length of a fiber. Crimp affects hand, cohesiveness, resiliency, stretch, bulk, heat retention, abrasion resistance, and absorbency. Crimp exists naturally in wool, and it can be added to manufactured fibers.

Properties:

Abrasion resistance is a fiber’s ability to resist damage from rubbing.

Absorbency (or moisture regain) is a fiber’s ability to take up moisture.

Chemical reactivity describes how a fiber responds to specific chemicals such as acids, alkalis, oxidizing agents, and solvents.

Density (or specific gravity) is the measure of the mass of a fiber per cubic centimeter. Specific gravity is the ratio of a fiber’s density to that of water (which has a density of 1g/cc at 4oC). Fibers with a specific gravity less than 1 float, while those whose specific gravity is greater than 1 sink.

Dimensional stability describes a fiber’s ability to retain a size and shape.

Drape describes how a fiber hangs over a three dimensional form.

Dyeability is a fiber’s ability to take up and retain dyes.

Elasticity is the ability of a fiber to return immediately to its original length.

Electrical conductivity is the ability of a fiber to transfer electrical current. Fibers with high electrical conductivity do not develop a static charge.

Elongation measures how much a fiber may be stretched without breaking.

Flammability is a fiber’s ability to burn. It describes how the fiber reacts to ignition sources, and at what temperature the fiber will ignite (if it is inflammable).

Hand describes how a fiber feels. Is it smooth, harsh, silky, dry, clammy, etc.?

Heat conductivity (or thermal retention) is the ability of a fiber to retain or transfer heat. It describes the insulation properties of a fiber. Fibers with low heat conductivity (high thermal retention) are good insulators.

Heat sensitivity describes how a fiber reacts to high heat. Does it shrink, soften, melt, discolor, or ignite if exposed to high heat, and at what temperature will it do so?

Loft is the ability of a fiber to spring back to its original thickness after being compressed.

Luster is the amount of light reflected from the surface of a fiber.

Mildew resistance describes a fiber’s ability to resist the growth of mildew, mold, and fungus.

Moth resistance is a fiber’s resistance to insect damage. It describes which insects (if any) will eat the fiber.

Pilling is the formation of balls of fiber (pills) on the surface of a fabric.

Resiliency is a fiber’s ability to return to its original shape after bending, twisting, and crushing. Fibers with high resiliency resist wrinkling.

Shrinkage resistance is a fiber’s ability to retain its original size through use and care.

Sunlight resistance is a fiber’s ability to withstand damage and discoloration from sunlight.

Tenacity is a fiber’s strength measured in grams per denier. The breaking tenacity of a fiber is the force required to break the fiber. Moisture affects a fiber’s tenacity, so the breaking tenacity is measured both dry and wet.

Texture is the nature of a fiber or fabric surface. It describes the way a fiber or fabric appears.

Thursday, February 25, 2010

Fitting a skirt

My apparel design class began work on our skirts last week. We are not doing this to learn how to make skirts, although that is a nice skill to have. We are making skirts in order to learn how to adjust a pattern to fit a real person. Anyone who has worked with a commercial pattern knows that pattern sizes and ready-to-wear sizes have little in common, and that without some alteration the finished garment will not fit perfectly. But how do we make these alterations?

I am going to school to become a designer; my goal is to design garments instead of using someone else’s designs. I will take a pattern drafting class next semester, but I must first learn how to construct garments and how to ensure that they fit properly.

The first step was for everyone in class to be accurately measured. The purpose of that day’s class was for us to learn how to take measurements, but it also proved to be a camaraderie building experience. Convenient as it might be to take these measurements in our skivvies, modesty won out and we wore t-shirts and shorts.

Step two was purchasing a pattern. The women in class will make skirts for themselves, and the men will make them for a mannequin. My pattern size was determined by the mannequin’s hip and waist measurements. Fortunately the mannequin’s shape is similar to that of the ideal woman for whom patterns are designed, so I did not have too many alterations to make. Some of the women in class who are curvier than mannequins need to make some large alterations. I may have those issues with the pants and shirt. I chose the simplest skirt pattern I could find. I do not want complicated construction details to distract me from the alteration details which are difficult enough.

We used our body measurements to determine what adjustments to make to the pattern, but before we started altering the patterns we had to learn how to do so. We used half scale paper skirt patterns to see how various adjustments are made.

After a long and often confusing lesson, I now have a basic understanding of how to alter skirt patterns to fit different hip and waist sizes. I do not yet feel comfortable doing it without consulting my textbook at every step, but it is a good start. I make alterations to similar paper patterns at the start of my pants and shirt projects too, but this is just an intro to fit and alterations. I will learn a lot more about it next semester in the pattern development class.

I made a few small changes to my pattern, then used it to make a muslin. I put the muslin on the mannequin and discovered I needed to make a few more alterations. I took in the side seams ¼” at the waist and 1/8” at the hips. I let out and shortened the darts. I put the altered muslin on the mannequin before cutting my fashion fabric. The new side seams were good, but I decided to go back to the original darts.


I pressed the muslin before I used it to evaluate fit, but I did not have a camera with me at the time. Today I had a camera but neither the time nor inclination to press the muslin. My time was better spent attaching the zipper to my fashion fabric. I will write something about that in a day or two.

Wednesday, February 24, 2010

Sociology/fashion design project – a plea for assistance

Apparel design students at UW-Stout are required to take one sociology class. I find the class interesting, although I am not sure if as a designer I will ever use what I learn in the class. My final project is to use the concepts from the semester to construct a sociological argument about a problem at UW-Stout. In order to make this class more relevant to my major, I decided to find a topic that relates to apparel design. I have noticed that as a man I am part of a very small minority in my program, so my paper will be about gender disparities in the apparel/fashion field.

The paper is due on April 29, but we were given the assignment last week so that we will have ample time to collect data. I found graduation numbers for 1988 through 2009 (data were not available for 1989, 1991, 1992, and 1999). In that time UW-Stout awarded 351 bachelor’s degrees to apparel design students. Only 13 of those degree recipients were men.

Are these data typical of fashion design programs at other schools? I would like to hear from students at other schools about the make-up of their design programs. What percentage of the students are men? I am interested in both quantitative and qualitative data. Men, how do you feel about being a student in a predominantly female field? Do you experience any problems because of your gender? What are they, and how do you overcome them? Women, what do you think about men in fashion design?

Any input about this matter will be greatly appreciated. Please post your comments to this blog or email me at coled@my.uwstout.edu. Thank you.

The identity of all respondents will remain confidential.

Wednesday, February 17, 2010

The joy of pockets

My tote bag project included a pocket. I had experience with similar pockets, but for this one I had to miter the corners in a way I had not done before. This type of corner adds a little time to the pocket making process, but it is not too difficult or time consuming. Making pockets is fun. I need a lot more practice before I can make the perfect pocket, but every pocket I make is better than its predecessor. I wish to share with you the joy of pockets. There are many types of pockets out there. This is just one of them, and my method is just one of many for making this particular type. I posted instructions for this type because it is the one with which I am most familiar. By the end of the semester I will know how to make at least three more.

Step 1: Cut out your pattern piece.

The piece will be 1” wider and 1 ¾” taller than the finished pocket. Pockets will usually be cut on the lengthwise grain, but if you are working with stripes, a plaid, or a print you may want your pocket on the crosswise grain or bias for aesthetic purposes. The white line is a fold line that we will get to in step 7. On patterns it may be marked with a line or with notches.

Step 2: Fold in the edges.

Fold in the sides and bottom ½”. Press.
At this point it is possible to skip to step 6, but if you do so the corners of your pockets may bulge out a little. If you are using light weight fabrics it probably will not be a problem, but with heavier fabrics you should use steps 3 through 5.

Step 3: Mitering the corners, part 1

Unfold the edges at the bottom corner, but do not press. Fold in the corners at a 45 degree angle so that the fold lines line up. Press.

Step 4: Mitering the corners, part2

Fold the pocket so that the wrong sides are together. The bottom and side must line up. Stitch along the fold line from step 3.

Step 5: Mitering the corners, part 3

Trim off the seam allowances from step 4. Press the corners.

Step 6: Pocket hem, part 1

Fold in top of pocket ¼”. Press

Step 7: Pocket hem, part 2

Fold the top to the right side of the pocket along the fold line mentioned in step 1. Press only the corners. Stitch along the side fold lines. Cut off part of the seam allowance.

Step 8: Turn

Turn the pocket.

Step 9: Topstitch

Topstitch the top of the pocket 1/8” above the bottom of the hem. Topstitching should be done on the right side of the pocket. The needle thread looks better than the bobbin thread. Backtacks will show, so you may wish to pull the thread to the wrong side and tie it off.

Step 10: Attach pocket

Attach the pocket to your garment by edgestitching 1/8” (or less) from the edge of the pocket. The top of the pocket must be reinforced with additional stitching. I like to stitch two or three stitches along the top and make a triangle (right). Another method is to make a rectangle and continue topstitching along the edge of the pocket 1/8” in from the edgestitching (left). There are many more ways to attach these pockets. The differences are more aesthetic than functional.

This style pocket can be found on shirts. I used denim because I had some scraps available. The back pockets on jeans are a little different. I prefer broadcloth to denim for shirts, but for a demonstration I do not think it matters. If you use a contrasting color thread your topstitching must be perfect. Mine is not. Matching color thread is more forgiving if your stitch lines are not perfectly straight. I like pockets; they hold my stuff.

Monday, February 15, 2010

Tote bag: important lessons from a simple project

On Friday I turned in my tote bag, the first project for my apparel construction class. I do not think anyone at my school harbors dreams of becoming a tote bag designer, but we all begin our apparel design studies by making one. Tote bag construction is a simple process, but in making this bag I learned some valuable lessons that will serve me well throughout my sewing career. Making this bag seemed to serve some additional purposes too: it introduces students to the apparel construction process, and it marks us as apparel design students.
Sewing the bag seems to be a rite of passage for apparel design students at UW-Stout. There are other items we will all make, but the bag is the one I hear mentioned most. I do not know if construction students all have a special tool or if education students all have a special red pen, but every apparel design student has a tote bag. I see students in their fourth year of school use the tote bag they made as freshmen to carry the supplies for their senior projects. Had I know that I am destined to develop such an intimate relationship with my bag I probably would have used a different print.

We were not given enough time in class to complete the bag. The only way to finish the project was to work on it in the open lab sessions. Students are permitted to work on their projects at home too, but at certain points in the construction process an instructor or lab supervisor must sign off on our work before we can continue. I finished my bag well ahead of schedule as did some of my classmates, while others are struggling to finish it on time. Late assignments are not accepted. I hope everyone in class finishes the bag and that they now understand the importance of good time management for our sewing projects.

Before this semester I would not have thought of a tote bag as a college level project, but I now understand that a simple project is the best way to teach the important skills that form the basis of advanced techniques. We had one lesson just about pressing fabric. Everyone knows how to iron, but there is a lot more to it that most people realize. We learned about pressing equipment (ham, sleeve board, point presser, pounding block, needle board, seam roll, press cloths) and how to press fabrics without damaging or distorting them. I did not know that I should iron in the direction of the fabric grain, nor did I know to press seams flat to set stitches before pressing them open. I have a few yards of corduroy at home. I knew about nap, but I had never heard of a needle board. I am glad I did not try pressing my corduroy before this lesson. I used to think I knew how to iron, but now I worry about what I do not yet know.

My fabric is a 60% cotton, 40% polyester blend. It took a while to find a setting on the irons that would not damage the fabric. I was smart enough to test the iron on scrap pieces first. I found the fabric in the drapery section of Hancock Fabrics. It was on sale for $3.00 per yard, down from $12.00. Nobody wants drapes with a print that is five years old.

The measurements for the bag’s pieces were posted to the class web page. All the pieces were rectangles. It would have been easy to measure the rectangles onto the fabric and cut them, but we were not allowed to do so. We had to make pattern pieces, pin the pieces to the fabric, then cut. Learning how to make a tote bag was nice, but learning about patterns will be more useful. I do not expect to make too many more tote bags, but I will use lots of patterns.

Before we could lay out the pattern pieces we had to ensure that our fabric was on grain. Last semester I could simply measure from the grainline on the pattern piece to the selvage, but that method is no longer good enough. Now I begin by pulling a crosswise yarn and cutting along the line it makes. I then fold the fabric so that the selvages are parallel and see if the crosswise cut I made is perpendicular to the selvage. No one in class had fabric that was perfectly on grain. What can you expect for $3.00 per yard? The way to straighten the fabric is to have two people grab the short corners of the folded fabric and pull in the direction of true bias. Fold, check, pull, and repeat until the fabric lines up right.

The bag’s seams were finished with a serger. I would have preferred to make enclosed seams or to hide the seams with a lining, but my ability to follow directions is a large portion of my grade. Projects I work on now must be made the way their designers intended. Once I begin designing my own items I will be able to make them as I please.

The straps were the most difficult part of the project. Sewing them was easy as was attaching them to the rest of the bag. The problem was turning them right side out. The pattern pieces were 3” wide and 31” long, and we used a ½” seam allowance. Turning each strap took more than 15 minutes. The rest of the project seemed quite easy. I worked slowly because I wanted to do everything as best as I could. I do not yet know how demanding my instructor is. I hope I get a good grade on the bag. I may need it to balance out my grades for the other projects which will be a lot more difficult.

Yesterday I began work on a shirt at home, and in class today I will start work on a skirt, but the next item I finish will be another tote bag. My instructor is allowing me to use the industrial lockstitch machines in the lab so that I will not lose the skills I picked up last semester. I may not use the industrial machines for class projects, but I can use them for my own stuff. I bought some nice fabric for a shirt, but the first thing I will make is a tote bag. Every industrial machine has a unique personality, so I want to become accustomed to the lab machines before I start work on something complicated. A tote bag will let me do this. It will be my fourth tote bag of the semester. I made two at home as practice and one in class. I have no idea what I will do with all these bags. Anyone need one?