Thursday, 19 May 2016

Knits 101... an introduction

Knit garments are very present in the fashion industry, since decades, and so are they in your wardrobe. You might eventually wish to make yourself a knit garment, but it is very important to know a few things about these knits. As the name indicate it, they are knitted and not woven, which make most of your sewing knowledges non-applicable for these. But this is no big deal... because today I will show you, in this article, the basics for sewing with knits. Once you've got through this article, you'll understand them better and will be sewing them with confidence! Let's do this...

Types of knit
The two most common knits are "Jersey" and "Interlock". These names actually refer to the way they are knitted, which means that the yarn used can be made of any fibre (cotton, viscose, nylon...). A jersey knit has two faces (a wrong and a right side) and tends to curl at the edges. Interlock knits have only one face and does not curl at the edges.

Double knits are thicker and are made of two layers knitted together. They are usually firm and does not stretch as much. The most common type of double knit is "Ponte di Roma" or simply "Ponte knit". They are often featured in structured garments.

Knits are commonly made with the following fibres: cotton, viscose, polyester and nylon. It is very important to choose the right fibre as the look and drape of your garment will be affected.

A knit with cotton creates a casual look. It does not drape very well and can be stiff, therefore it is best to use for a t-shirt or even a basic bodycon skirt. Cotton is also a healthy choice as it is breathable and is the ideal fibre to use when making underwear.

A knit with viscose (AKA rayon) or polyester will have a lot more drape than cotton. They are your best option when making loose or draped/twisted garments. They also have a more sleek appearance.

A knit with nylon (AKA polyamide) is mostly shiny and slippery. It is the perfect choice when making sportswear, swimsuits and lingerie. It dries fast but due to its synthetic nature, nylon fabric is not heat resistant. When making lingerie or swimsuits, it is best to line the crotch with a piece of cotton knit. 

Spandex is the key to a good knit. Spandex, also know as elastan or "Lycra" (a brand name), is a clear synthetic fibre added to a fabric to increase its elasticity. Knits are already stretchy but spandex will make them "elastic". A knit without spandex will stretch but, once stretched, will hardly come back to its original shape. For this reason, it is very important to choose a knit with spandex when making tight fitted garments. Spandex is clear, therefore not visible, and can even be added to regular woven fabrics such as denim or twill.

Stretch percentage
Every knits has a different stretch; some will stretch a lot and some will be more stable. This factor must be taken in consideration when a pattern cutter is drafting a pattern for knits. This is because the pattern must be shrunk accordingly or the garment will hang loose or be too tight on the body. These days, most patterns for knits include a gauge so you can test your own fabric. If your fabric doesn't stretch enough, you might want to use one size bigger to compensate. If you can hardly reach the indicated percentage, it's better to choose another fabric with a better stretch, as it might affect the fit and comfort of the garment.

You might also come across "4-way" or "2-way" stretch knits. Always check on the pattern to see what kind of knit is requested. A "4-way" stretch knit means that it will stretch along the weft and the selvedge, and "2-way" means that it will stretch along the weft only. A firm knit stretches a little and usually along the weft only. A moderate knit stretches more but still along the weft only.

Fabric preparations
Yes, just like regular fabrics, knits to be prepared before cutting into it. Always wash and dry them as you would normally do with a garment. Ensure to wash nylon knits at low temperature and do not put them in the dryer. No matter what type of knit you are working with, if you let it dry, ensure that it is laid flat and not hung. Knits with synthetic fibres must also be ironed at low heat.

When you start mingling with knits, you need two important notions: a stretch needle and polyester thread. As a matter of fact, the most common all-purpose thread is made of polyester, so chances are that you already have them in hand. The reason why you must use this kind of thread is simply because it is more elastic than cotton threads. Stretch needles are very easy to find at the sewing shop and are completely mandatory! A stretch needle has a rounded tip that will not damage the yarn because it does not pierce through the fabric but instead, move the yarns around the needle. I highly suggest that you get an assorted set of stretch needle with various sizes. You may experience skipped stitches which will be caused by an inappropriate size needle. Knits also come in different weight so it's important to match the needle size accordingly.

Stretch stitches
Depending on your sewing machine, there are many types of stitches that you can use for knits. If you have a recent model, chances are that you have all sorts of fancy stretch stitches. Do not hesitate to check the manual and experiment with these. But if you do not have that many stitches on your machine, or prefer to keep it simple, the zig zag stitch is there for you! Every sewing machine has a zig zag stitch which can be changed in width and length. 

Before you start sewing...
As always, I recommend that you make a tension test on a fabric leftover to check not only the tension but also the stitch length and width. A zig zag might create a "tunnel" or a bulge in between the stitches when too wide, especially with thin knits. A too short zig zag can create a wavy seam and a too long one will most likely results in a non-stretch seam that will break easily once stretched. Get the balance right!

To assemble, use a very narrow and short zig zag stitch. This will resemble to a straight stitch and will create a solid and stretch seam. Then, you can line it with a regular zig zag stitch and trim the allowance around it. The regular zig zag is not mandatory but recommended with curly jerseys, to help keeping the edges flat.

To hem, use a regular zig zag stitch, a double stretch needle and if you have it, the invisible stretch stitch can also create beautiful and clean hems too. The double stretch needle is very interesting when sewing with knits as it creates two rows of straight stitches with a zig zag underneath, to keep the seam stretchy. If you wish to work with a double needle, ensure that it is adapted for knits and that you have two spools of thread available. If you don't have a dedicated place for a second spool on your machine, wind up a second bobbin and thread the machine as you would normally do using this bobbin. 

Hungry sewing machine?
Depending on the type of knit you are using, it might tend to fall into the needle throat, which is very annoying. This is not because your sewing machine wants to eat the fabric... but mostly because knits are not firm, sometimes slippery, and tend to slip in there very easily. This can be stopped by "stretching" the knit very lightly... but all you are looking for is to add some tension - be careful to not overstretch the knit.. By doing so, you will notice that the fabric will be easier to control and will not get eaten by the machine! Also, start the seam slightly below the fabric edge. These are little details that will make a huge difference when sewing!

Now you know enough to start sewing with knits! Experiment and don't be scared to make mistakes. For a start, I suggest using an easy pattern that does not require any special trims, such as our free batwing top! I hope you liked this article and do not hesitate to leave a question in the comment section!

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