Ever wondered how to sew with knits? Or, even how some sewists are so brave to even try? If so, bear with me for a while. I am going to try to convince you that knits are not only easy to work with, they are EASIER. And, they are much more fun!
Here is the truth:
Knits are not harder to work with, they are just different. In order to understand (and even love them), you need to learn a bit about them.
let’s answer the most important questions about knit fabrics.
- 1 What is knit fabric and how is it different?
- 2 How to cut knits?
- 3 How to sew with knits
- 4 What seam allowances to leave?
What is knit fabric and how is it different?
Types of fabric can differ on the way they are produced and the materials, used to produce them. Fabrics, used in clothing can be knitted or woven.
What is knitted fabric and varieties of knitted fabrics
Knit fabrics are manufactured by creating a repeated rolls of loops. Knit fabrics are made from only one set of yarns, all running in the same direction. Some knits have their yarns running along the length of the fabric while others have their yarns running across the width of the fabric. Knit fabrics are held together by looping the yarns around each other. Usually, knit fabrics are stretching even if they do not have elastic thread included, as a result of their structure.
Knitted fabrics include mesh, lycra, cotton jersey, viscose/rayon, interlock knit, etc.
are made from two pieces of yarn that are stretched out over a loom and woven together in both horizontal and vertical directions. Usually, woven fabrics do not stretch because their fibres run at 45-degree angles to one another. It is possible to have a stretching woven fabric if there is elastic included in its structure.
Woven fabrics include linen, denim, twill, satin, chiffon, tweed, canvas, etc. There are thousands of varieties of fabrics on the market, both woven and knitted. You don’t need to know all of them. What is important is to make a difference between woven and knit fabric, because they are designed and used for a different purpose and have distinctive qualities. If you want to learn more about fabric names, there is a full list of both woven and knitted fabrics by their names.
Beginners find it harder to work with knits because they stretch and the edges of the fabric roll. I find this to be an advantage, because details get assembled easier. You can pull and stretch a bit so the details match. It requires some practice, but there is nothing to be overwhelmed about. Knit and woven fabrics have specifics and different basic techniques to work with. My first steps in sewing were with knits and I honestly find knits and jersey fabrics easier to sew than woven ones. They are more responsive to adjustments and tolerate small mistakes better than wovens. And in my opinion, they are way more fun and offer a greater variety of use.
Woven and knit fabrics react, sew and look different. Nothing is more important for the end result than choosing the appropriate fabric according to the project you are starting. Usually, you can rely on the pattern to point out the most appropriate fabric choice. If not, as a general rule wovens require darts, zippers and ease while knits look good without those.
How to cut knits?
The first step when working with knits is cutting. Make sure you have chosen the right knit fabric for your project. For example, I usually choose lycra spandex for leggings and a cotton jersey for a T-shirt.
Steps before you start cutting the fabric:
Preparing the fabric:
1.Relax the fabric.
When sold, fabrics are usually displayed on bolts or cardboard tubes. This changes the usual shape of the fabric, especially if it is a stretchy one. It is very important to unfold the fabric or the quantity of it that is going to be used and leave it to relax for at least twenty-four hours before cutting. This will prevent the fabric to go back to its natural form after your project is done and twist the garment.
2.Preshrink the fabric.
Many fabrics shrink when they get in contact with heat and moisture. This is usually true for natural materials like cotton. That is why in industrial sewing the patterns for cotton T-shirts are sometimes left 1-2 cm longer in order to tolerate shrinking after washing. Very often it is hard to tell what is the fabric made of exactly, so I would suggest preshrinking any fabric before beginning the sewing project.
3. Iron the fabric is also important.
Especially if you washed it to prevent shrinking, the fabric might have some wrinkles. This might take effect in the cutting process. It is important to cut when the fabric is completely relaxed. The wrinkles can add up centimeters/inches to the detail when it get ironed at the end. The fabric shouldn’t hang over the cutting table. This is very important for knits because they stretch when hanging over. The more precise you cut, the better the ready garment will fit.
4.Test your fabric for color fast, if the garment is made of different pieces of main and additional fabric.
I’ve messed up big time in the past because I forgot to make a test for color fasting. You don’t want to finish a garment, wash it and …. ruin it. Although it is a tedious task, it is a must be done when you have contrast fabrics on the same garment.
5.Mark the right side of the fabric.
It is essential to cut all the pieces on the right side of the fabric. Prepare the pattern. Determine the size, alter it where necessary and cut it out. Position the details of the pattern on the fabric. This will help you minimize the fabric waste and avoid unpleasant surprises. Be careful about the straight grain of the fabric. Very often the edges of a knit fabrics don’t match the straight grain. When folding the fabric, finding the grainline (straight grain), is very important. Things might seem ok when cutting and sewing, but once you wash your garment, it twists on the seams and takes unnatural forms. Have in mind that sometimes the details are cut off grain and some are cut on the fold and this is fine when it is specified in the sewing instructions of the pattern.
Prepare the tools you are going to need: scissors or cloth cutting machine, chalk, pins, the pattern, a liner, a measuring tape.
For knits, I prefer to use a cloth cutting machine because it cuts precisely next to the pattern outlines. When I use scissors I unintentionally leave a bit bigger seam allowances than I want to. Also, a cloth cutting machine can handle several layers of fabric which is useful when you cut two or more details faced together like sleeves for example. The edges of the fabric stay smooth, without edges left by the scissors. And also, if you produce more than one piece this will help cutting faster and more precisely. Don’t get me wrong – scissors are perfectly fine, too.
Instead of traditional chalk, I prefer to use a water soluble one or even a sliver of soap. They fade away when I iron, which is important having in mind the smaller seam allowance we leave on knits.
How to sew with knits
As you already know, knits stretch and regular straight stitching easily breaks and the threads pop out. To manage the stretching of the fabric, you need to use stitching that tolerates the stretching.
The best choice would be an overlocker / serger machine. The loops of the thread make the seam extremely durable and tolerant to stretching. If you don’t have an overlocker, you can use your regular sewing machine to sew the knits and it can look as good on the outside as if it was professionally manufactured.
To achieve that, use a zig-zag stitch instead of a straight one. You can see a lot of zig-zag stitching on bathing suits because it tolerates the stretching as good as the overlocker seam. The unpleasant part is that it is harder to remove if you made a mistake. The width of the stitch can also be regulated, depending on the specifics of your sewing machine.
TIP> When using the serger/overlocker it happens that the seam ruffles. Usually, this happens on fabrics with more elasticity. You can reduce that by regulating the tension on the serger and by ironing. Ironing while sewing is inevitable. If you want to make your stitches precise, no matter if the fabric is woven or knitted, you have to iron a lot DURING the sewing, not only at the end. I like to say that ironing is half of the sewing.
What seam allowances to leave?
When working with knits you don’t need to leave big seam allowance because it goes into the seam. So the seam allowance depends on the width of the seam. Have in mind that eventually you can cut a bit of excess fabric with the serger, especially if you are a beginner. If you use the zig-zag seam on a regular machine the excess fabric stays in and it can be visible on the face when done.
TIP> I always test my stitches on a piece of the fabric, before starting the project. I test how it handles stretching and how it looks in general. You can make some adjustments, depending on your type of machine, the seam might get thicker or rare. A thicker seam usually tolerates stretching better.
Choose the right needles, width, and length of the stitch.
If you sew knit fabric on a regular sewing machine, you have to pick the so-called jersey or stretch needles. They have a ballpoint tip that goes between the loops of the fabric easily and doesn’t break it. If you sew on a serger/overlocker usually a middle sized needle is ok for most knitted fabrics.
Finishing off the knit garment.
There are several different ways to finish the ends of a knit fabric garment.
Bindings are very often used with knits for finishing the neck opening or the armholes. Binding not only looks good, it helps to gather and hold the fabric together at places that are stretched intensively.
When sewing knits, hems are usually done on a cover stitch machine. It is the most common choice in industrial sewing. It makes two straight stitches on the right side of the fabric and a set of loops on the wrong side.
Some sergers have the cover stitch option included. You can also finish with binding, zigzag stitch or a catch stitch, although in my opinion a catch stitch looks a bit heavy on knits, especially on jerseys. Or, you can choose to leave the knit fabric unfinished, because it won’t unravel like a woven one.
Most sewers I know who are learning to sew tend to avoid the knits as too complicated and hard to work with. I actually find them easier, BUT there are specifics when working with them. I think that all the trouble sewers face when using knits is because they try to sew them as if they were woven fabrics. If you follow the guidance above and practice a little you might be surprised to find out that you actually prefer knits.