Whether you are new to sewing or have been sewing for years but you have yet to tackle knit fabrics, this is the place for you.
To get started you should know what is knit fabric? There are 3 main types of fabric, Woven, Non-woven, and Knit. Woven fabric it when the fibers are woven together like a basket (shown above) these fabrics typically have no stretch except some on the bias (diagonal) grain of the fabric as the weave shifts in a stretch like motion. Non-woven fabrics are when the fibers are synthetically bonded to each other instead of woven or knit together, think neoprene, or plastic like fabrics. Then there are knit fabrics. In which a single fiber is looped together. These fabrics typically have stretch crosswise and some have stretch in up to 4 directions, depending on the fiber content and knit pattern.
There are 2 basic types of knit fabric. Warp knit (like most knit fabrics) and Weft Knit (like a hand knit sweater) while warp knit can be cut and the “raw edge” will not unravel a weft knit will unravel when cut. Most knit fabric has stretch to it which makes it desirable to wear and therefore sew with. The amount of stretch each knit has depends on what it is made out of and how it is knit together.
Let’s discuss the types of Knits:
- Jersey: It can be made from wool, cotton or synthetic fibers. Jersey typically has a “right and wrong” side as the front will be flat and smooth and the back will have slight ribs to it. This fabric will often roll or curl along the raw edge. While some Jersey will have stretch especially if they are made with a synthetic fabric such as spandex or lycra, many jerseys won’t have much stretch at all.
- Double Knit or Interlock: It may also be made from wool, cotton or synthetic fibers, although you will most often find interlock made from cotton. It’s the best fabric to start out with since it is a “sturdy” knit. It is made when essentially 2 single knit (jersey) fabrics are knit together making them one piece. While interlocks are always one solid piece of fabric some fabrics categorized as double knits where they are two sided knits bound together and could be separated. Either way both are great to start out with, they don’t curl at the edge, and they have manageable stretch.
- French Terry: It is flat and smooth on the front with course loops on the back. (like a towel) while french terry is very different from sweatshirt knit, more commonly sweatshirts are made from a french terry than a sweatshirt knit.
- Sweatshirt Knit: Flat and smooth on the front and fuzzy or soft on the back. Knit together in a jersey knit and often they have little to no stretch. It’s important to keep that in mind when using it with a knit pattern since knit patterns often have negative ease and so a bulky and thick fabric with little to no stretch will make it difficult to wear.
- Sweater Knit: Made much like a hand knit sweater a sweater knit mimics a sweater. While most are weft knits and will unravel at the edges, you can find some in a warp knit as well.
- Rib Knits: Have actual ribs in the fabric that are visible on both sides. This is most commonly used for neck bands, due to the great stretch and recovery, but it can also be used to make most anything as it has great stretch to it.
- Ponte or Ponte De Roma: Smooth and flat on the front with subtle ribs on the back. Much like an interlock or double knit they are great for beginners as they are also a sturdy knit and typically have great stretch and soft drape.
When dealing with knits of all variety the most important thing to be aware of is content of the fabric. What fibers came together to make the knit? This will determine the stretch, recovery, weight, drape, shrinkage, and over all feel of the fabric. While knits used to only be made from wool or cotton, there are now many synthetic fibers that make up a knit fabric or are blended with wool or cotton to create the fiber. Let’s break down the different types of fibers and what they do to a fabric:
- Rayon: Is a semi-synthetic fiber, since it is made from natural substance but not in a “natural” way. Rayon mimics silk in fabric which will add to or make a fabric slippery, smooth, and soft. It increases drape, but it has the lowest stretch recovery, which means if it is stretched out it won’t bounce back. Keep that in mind when selecting fabrics. Different types of rayon include, viscose, and modal, so check for those terms to know its under the rayon family.
- Polyester: Typically a synthetic fiber although there are some natural polyesters. Polyester is often used due to it’s high retention of color, and wrinkle resistance. It can easily mimic silk in fabric providing a softness and sheen to the knit.
- Spandex: This highly stretchy synthetic fiber which may also be grouped with lycra or elastane. It’s strong, and stretchy and has great stretch recovery, meaning it can be stretched to the max and bounce right back down to size. Often adding an almost rubber like texture to the knit (like swimwear) the bouncy knits are great.
- Cotton: Made from nature and a great natural fiber. 100% cotton knit is not typically very stretchy as the fibers don’t stretch just the manner in which it is knit together. This is why cotton is often blended with another fiber like lycra or spandex to add to the stretch of the fabric. Cotton is very breathable and soft so it is a fabric of choice for many.
- Wool: Another natural fiber. Wool is also often blended with other fibers for a number of different reasons. Wool alone does not typically have good stretch recovery, it can also shrink quite a bit.
Stretch and Stretch recovery:
One of the most important things to know before you start sewing with knit is understanding the stretch and stretch recovery. The amount of stretch a fabric has is typically measured in percentage. Most knit patterns will tell you what percentage of knit stretch is required. Why is this important? Many knit patterns are designed with negative ease, meaning it’s designed to be made with fabric that will stretch when worn so the pattern is smaller than your actual measurements. However if your fabric does not stretch enough the outcome may be too tight, or too small. To find the stretch percentage all you need is a 10″ strip of the fabric, (make sure the 10″ runs along the stretch grain of the fabric) and a ruler. Place one end of the strip at the edge of the ruler. Then hold it in place with your hand and stretch the other end as far as you can. If it stretches to 12″ then the fabric has 20% stretch, 14″ and it has 40% stretch, 16″ and it has 60% stretch and so on. Loose fitting knit garments don’t usually require a particular amount of stretch, incase you find yourself with a knit with very little stretch, leggings however usually require 50% or greater for the best fit.
Another element to stretching is stretch recovery. Some knits (like rayons) will stretch a ton which is great but they stay stretched out, this means they have horrible stretch recovery. Why is this a problem? If you were making a neckband for example, the whole purpose is to stretch it out while you sew and then the neckband bounces back to shape the neckline and make it hang well. The neckband needs to stretch to fit over a head, but if the fabric has poor recovery, then it would stretch and stay stretched so you would have a wavy neckband. To test the stretch recovery, take your same 10″ you stretched to test and measure it again after it’s stretched. If it is 10″ again it has great stretch recovery, meaning it bounced right back to proper size, if it’s anywhere in between the stretched size and 10″ then it doesn’t have the best recovery.
Before you start sewing there are a few tools you should have.
- Ball point needles– Using the proper needle for knit fabrics will help any machine sew better. Euro-Notions Ball Point Jersey Machine Needles
- Stretch Foot– Many machines have additional sewing feet you can purchase, including a stretch foot which works with a stretch stitch to create a seam that will stretch even when sewn with a normal sewing machine
- Twin needle– If you don’t have a stretch foot, but you want to sew knits with a regular sewing machine use a twin needle for hems and neck binding you will get a professional look with a stretchy stitch just by sewing a straight stitch. Schmetz Twin Assortment Needles Sz1.6/70, 2.0/80 and 3.0/90
- Overlocker/serger– If it’s in the budget, purchasing a serger is a great way to sew with knits as it sews an overlocked seam that will stretch with the knits. Brother 1034D 3 or 4 Thread Serger with Easy Lay In Threading with Differential Feed
- Cover stitch Machine– Another great machine for sewing hems and neck lines is a cover stitch machine. It sews a double row on top and chain stitches on the back that allow your fabric to stretch even after being sewn. Brother 2340CV Cover Stitch
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