Sewing with knit fabrics has been deemed as a scary process by many. Knits are sometimes unpredictable. If incorrect thread tension is used, the fabric puckers. If the wrong needle is used, tears occur in the fibers.
While these problems are common when working with knit fabrics, there are many ways to avoid them and sew a beautiful garment. Most of these problems occur because not much is known about the stretch in the knits, how the fibers are weaved together, and what type of thread, needle, or tension level should be used. To avoid some of the common pitfalls of working with knit fabrics, you should learn about the stretch in the fabric first. Before starting a project, first take a sample piece of the fabric and try out different stitches, thread tension levels, and sewing pace and see how the fabric reacts. Here are some important things to remember about certain stretch knits and how to work with them.
There are basically four different types of stretch in knits: Firm, Moderate, Two-way, and Super.
The least stretchy of all the fabrics, firm stretch knits have up to about 20% stretch across the grain. By rule of thumb, they are the easiest to work with because there is so little stretch. Most fabrics have a medium to heavy-weight and include double knit, sweatshirt knit, and boiled wool.
Double Knit: Double knits are made of tiny knitted and ribbed fibers that look the same on either side of the fabric. The ribbing and heavy-weight quality makes it a bit thicker, so ribbed knit fabrics perfect for skirts, dresses, jackets, and coats.
Sweatshirt Knit: Also called sweatshirt fleece, sweatshirt knits should not be confused with cotton fleece, which is stretchier. Sweatshirt knit is made of smooth, vertical ribbing on the right side and a soft fluffy surface on the wrong side. It is extremely easy to work with and perfect for cool-weather sportswear, jackets, and, of course, sweatshirts.
Boiled Wool: Mechanically knitted and washed for shrinkage, boiled wool is very soft and often used for scarves, hats, jackets, and other cold weather garments. Boiled wool is most commonly seen in dress fabric as well.
Moderate stretch knit fabrics are the most common knits and it is probably what you picture when you think of knit fabrics. An example of moderate stretch is fabric used to make t-shirts. Moderate stretch fabrics are made with single knit fabric, resulting in a comfortable, light to medium weight fabric that stretches from 25% to 50% across the grain. Moderate stretch includes cotton jersey knit, tricot, double-napped cotton fleece, interlocking knits, velour and stretch velvet.
Single Knit or Cotton Jersey: Lightweight cotton jersey knits are most commonly seen in t-shirts and tops. The ribbed knits appear vertical on the front side and horizontal on the wrong side. These knits are easy to work with and are commonly used for casual wear, such as tops, dresses, skirts, elastic-waist pants, shorts, and pajamas. Some knits are so soft that they are used in infant clothing.
Tricot: These extremely thin knit do not unravel, making them great for underwear and lingerie. Unlike single knits, tricot knit is a warp knit, which means that the ribbing on the front and back are parallel instead of perpendicular.
Double-Napped Cotton Fleece: The double napping of this versatile fabric makes it soft on both sides and thick enough for winter wear. The fabric makes warm pajamas, sportswear, blankets, scarves, hats, gloves, sweatshirts, dresses, jackets, and vests.
Interlocking Knits: These lightweight knits drape beautifully and can be sewn into dresses, tops, pants, shorts, skirts, socks, hats, gloves, and pajas, as well as baby clothes and diapers. While it doesn’t curl along the edges, the finely knitted ribs on both sides can unravel and require extra attention of runs on the cross grain.
Velour and Stretch Velvet: Both knits come in a variety of weights and have a soft brushed nap on the right side. With a moderate stretch, they can be sewn into dressier garments, skirts and dresses.
These stretchy knits are best turned to when you plan to make a swimsuit, leotard, or form-fitting garment. Usually stretch percentage goes from 50 to 75% in a two-way stretch fabric in both lengthwise and crosswise directions.
Sweater Knits: Sweater knits are available in a variety of weights, textures, fibers, and stretch percentage. Sweater knits are great for making winter wear, like pull-overs, cardigans, vests, dresses, ponchos, tunics, undergarments, and even accessories.
Cotton Lycra: One of the most popular types of two-way stretch fabric is Lycra. Lycra is the brand name for the synthetic fiber spandex invented by DuPont in 1958 and refers to fabrics that have synthetic fibers interwoven into fabrics to provided added stretch and flexibility. The more Lycra percentage in a fabric content, the stretchier the fabric will be. This synthetic material revolutionized the sewing and fashion industry because, while stretchier than most fabrics, it also has great recovery, allowing clothes to retain their shape.
Four-Way Super Stretch
Four-way stretch fabrics are one of the more trickier fabrics for sewing because it can stretch 100% in any direction. Swimsuits and sportswear are some of the most common examples of four-way stretch fabrics. Other types included rib knit, swimsuit knit, and action knit.
Rib knit: Made with any type of fiber, rib knits to do not always incorporate or depend on synthetic materials to achieve stretch. The stretch is created by the way the fibers are knitted. The stretch is 100% on the crosswise grain, creating a versatile finishing fabric for necklines, waistbands, cuffs, arholes, and hemlines. The edges of rib knits do not curl so these fabrics are highly favored for use on edges of garments.
Swimsuit: Swimsuit knits are usually made of a nylon-spandex blend, but the stretch will vary depending on the percentage of spandex integrated with the nylon. This fabric has more stretch on the lengthwise grain.
Action knit: These knits are somewhat similar to cotton Lycra, providing more give and stretch. They are typically used as to make sports apparel, such as biker shorts, running pants, sports bras, and workout tops. Action knits are a blend of nylon, cotton, polyester with spandex or latex added for flexibility. Most sports brands like Nike, Adidas, and Reebok have developed their own versions of action knit to be used in their apparel.