The Why of Sewing 3: Fabric Anatomy (Fiber Content)
This post is in a series I am starting that is going to talk about concepts in sewing and fiber arts and try and explain some of the whys behind the hows.
The beginner sewist is often (correctly) advised at the beginning of their journey to start with cotton fabric, sometimes specifically woven cotton, but not always. Nevermind that cotton fabric can vary from a tshirt to denim and canvas.
We have learned the difference between a knit and a woven fabric in my previous posts (check the tag #the why of sewing which should bring up the whole series). Let's talk fiber content.
Like fabric structure I basically break fiber down into two groups: natural fibers and synthetic fibers. Below I am going to talk about the fibers you are most likely to encounter as you shop as a home sewist. It is NOT a complete list of fibers, nor could I list the entirety of fabric types made with each fiber.
Natural fibers: these are fibers that come from plants and animals and require minimal processing to be made into fabric.
Wool: This comes from sheep, which are sheared 1-2 times a year. The animal is not hurt in the process and even sheep not raised for fiber production must be sheared for their health. Wool is warm, but breathable. It can be easy to work with in some ways, but it does shrink when washed and so many modern sewists avoid wool. Some folks have sensitivities to wool as well. Wool is most commonly used in suitings and knits.
Image: Shorn sheep in a verdant field (Source: By Roger Kidd, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=13035358)
Silk: Silk is made from the cocoons of silkworms, and generally harvested prior to the hatching of silkworm larvae. Silk is expensive to produce and considered a luxury good. Silk is shiny and lightweight, it can be surprisingly warm. Silk can loose its sheen in the wash and because the fiber is so delicate it can be difficult to sew. There is a lot of misinformation on the production of both silk and wool online. Worm Spit has been educating fiber artists about the process of making silk since 2002.
Image: a vintage style poster showing various stages of the silkworm moth (By Bibliographisches Institut, in Leipzig - Meyers Konversations-Lexikon, 4th Auflage, Band 14, Seite 826a (4th ed., Vol. 14, p.826a), Public Domain, https://commons.wikimedia.org/w/index.php?curid=2317808)
Cotton: Cotton comes from the cotton plant, there are several varieties commonly grown and it is the most common natural fiber used in textile production. The cotton fiber comes from the seed head of the plant. Cotton can be made into light breathable fabrics and warm cosy fabrics. The list of fabrics made from cotton might actually be endless but here are a few you might encounter: jersey knits, denim, quilting cotton, gauze, lawn, voile, sweatshirting, twills, poplin, oxford cloth, canvas...
Image: the cotton boll, or seed pod (source: Public Domain, https://commons.wikimedia.org/w/index.php?curid=689304)
Linen: Linen comes from the flax plant. The fiber comes from the long stem of the flax plant and can be difficult to break down into a usable state. It is also difficult for modern spinning equipment to make into threads, which is why linen tends to be quite expensive in comparison to cotton. Linen is cool to the touch and very strong. It also wrinkles very easily. Coarsely woven linen can be uncomfortable for some to wear. Linen tends to be made into simple plain woven fabric, occasionally knit fabrics, and can vary in weight from handkerchief linen (very fine, almost transparent) to canvas. I recently reblogged THIS POST which had some incredible links regarding linen production.
Image: linen cloth recovered from Qumran Cave 1 near the Dead Sea (Public Domain, https://commons.wikimedia.org/w/index.php?curid=248420)
Synthetic fabrics: these are fibers that have been manufactured through industrial processes.
Polyester/Acrylic/Nylon: These fabrics are plastic. They are made from different types of plastic, but ultimately a liquid petrolum product is extruded into a long filiment and made into cloth. They can be made into woven or knit fabric. The way they are made can have many different properties. Generally polyester is what you find in the home sewing world. Polyester is not breathable and because it is oil based it tends to hold on to smells. It melts when it is too hot and therefore can only be ironed carefully. Polyester also tends to be very strong and can help make very sturdy fabrics. Because polyester is very inexpensive to produce it is frequently combined with other fibers to reduce production cost.
A diagram of "dry spinning" polyester fibers (source: https://encyclopedia.che.engin.umich.edu/fiber-spinning/)
Spandex/Lycra/Elastine: this is the stretchy stuff! Generally found in combination with other materials this is what makes fabric go beyond the mechanical stretch that is produced by the fabric structure. In small amounts mixed with cotton it makes a fantastic tshirt jersey, 100% spandex is great for swim and dancewear. As we discussed in the knit article I posted previously adding stretch to sewing does make it more complicated to work with, but used wisely spandex is your friend. Best not pressed excessively as the fiber has a protein structure that breaks down when it is hot. Also if you have a garment or fabric with a lot of spandex content you might want to consider avoiding the dryer.
Rayon/Viscose/Bamboo/Lyocell/Cupro/Tencel: There are SO MANY names for cellulose fabrics. These are sometimes categorized as semi-synthetic fibers, or even put in with natural fibers. They are all the same thing deep down. Cellulose (generally sourced from trees and plants) is chemically broken down into its most essential parts and then extruded into a filiment. These fibers were originally developed as a silk substitute. Rayons are fine, breathable, and have a drape that clings to the body. They shrink in the wash and can continue to shrink through several washes. They also can be fragile when wet. Rayons are made into both woven fabrics and knits and they tend to be thin and fine fabrics. Rayon fabrics, especially those labeled as bamboo are frequently greenwashed as environmentally friendly, because they are sourced from a renewable resource, but the process of producing cellulose fibers is highly polluting and uses significant amounts of water.
While there are outliers, most textiles you will encounter while shopping for fabric will be made of the above fibers. A deeper dive into these would be fun, but I find at least 3 potential rabbit holes I could go down every single post I make here.
