Knit Fabrics: Top Tips for Sewing with Knit Fabrics
Sewing With Knit Fabrics in Your Fashion Creations
I had an email from one of my fashion creative gang last week. Her name is Ella. She mentioned that her biggest struggle at the moment was sewing with knit fabrics. And it got me thinking. Anyone that thinks of themselves as a sewing beginner is probably scratching their head at the different stretch fabric types, and how best to sew them. So this week’s post is written for Ella, but will apply to all you sewing beginners out there!
What Knit Fabrics Are Already In Your Wardrobe?
If you were to take a quick flick through your wardrobe or cupboards you’ll notice that most of your wardrobe is made up of drapey, loose fitting clothes or garments that are a little more fitted and structured.
Most of the time, the fitted pieces will have been made from woven fabrics and the draped clothes from knit fabrics. The exceptions are of course when a knit fabric has been tailored and possibly interfaced to add more structure, or when a woven fabric is very loosely woven, such as a chiffon.
Let’s Break Down the Fabric Options
The main options when selecting a fabric for your fashion creations are:
- Woven fabrics
- Non-Grain fabrics
- Knit fabrics
These are fabrics that are woven on a loom and have a warp thread and a weft thread.
These are fabrics such as leather, latex, plastics that have been man made and have no grain line.
Knitted fabrics are made from one or more long interconnecting and looping yarn, much like if we were to knit ourselves something in the traditional method. In garment manufacturing, knit fabrics are manufactured on big knit machines, as opposed to two knitting needles – can you imagine how long it might take otherwise? 😉
Being that knit fabric can be a bit of a mystery, I’m going to focus on that this week
Knit Fabric Variations
Within knit fabrics there are:
Jerseys, which are weft knits. This means that they have horizontal loops on the back, and vertical ribs on the front. Much like a stocking stitch when hand knitting.
Tricots are warp knits. This means that they have loops going in a vertical direction.
How to Tell if Your Chosen Fabric is Knitted or Woven
There are four ways to check which type of fabric you’re looking at:
The Sight test
Does the fabric appear to have lines crossing over each other or are they looking more like rows upon rows of narrow braids or loops?
The Scrunch test
My term to determine is the fabric wrinkles and crinkles.
The Stretch test
A knitted fabric will always have WAY more stretch across the width of the fabric than a woven. Unless a stretch element has been added to a woven, the most stretch will occur on the bias.
The Edge Test
Woven fabrics have a strong woven edge known as the selvedge, with occasionally has loose threads. Knit fabrics have little holes and sometimes glue blobs to prevent the fabric curling.
Types of Knit Fabrics
The most simplest of knits, it really does look like a traditional stocking stitch. It is usually quite thin and suitable for lightweight draped garments, and is known to distort easily. Probably due to it being easy and quick to produce compared to other knit types. Your twisty and turny seams on your tee shirts? Single jersey!
Rib is when you have raised and lowered lines running through the knit. Think of the cuffs on your sweaters. It could be 1×1, 2×1 or 2×2. This makes the rub fabric double sided and usually has a much higher stretch and recovery.
Made similarly to rib fabric, but on a circular machine. It is also double sided and can be quite heavy weight too.
There are also versions of woven fabrics which can have higher stretch than usual:
• If a fabric is manufactured with elastane (also known as Spandex or Lycra), it will have a greater amount of stretch than usual. The craze for skinny jeans a decade or so ago came about but to the elastane that was added to the cotton to give that extra bit of stretch. The more elastane is added to the mix, the stretchier the fabric will be.
• Bias Cut woven – as mentioned before, any fabric cut on the bias will have more stretch to it. The true bias is a 45 degree angle from the selvedge and gives beautiful drape when used well.
• Woven fabrics that have been constructed in special ways can have a greater elasticity too.
Using Different Patterns for Knit Fabrics
One question I get asked is the use of patterns with different types of fabric.
Is it ok to use a pattern for a woven skirt with knit fabrics. Can I use a tee pattern with a light woven silk?
The answer to these questions is yes – but with care.
A pattern that has been designed to be used with woven fabric will look very different when used with knit fabrics. This is because knit fabrics behave differently.
An added consideration is that knit fabrics will also stretch in different ways, by different amounts. The best way to know if a fabric will work is to do a stretch test.
Stretch Testing Knit Fabrics
One way to overcome this is to do a stretch test on your knit fabrics first. For this we need to cut a square of fabric.
I usually work with 10cm by 10cm square, but you can opt for a bigger amount if need be. I’ve included a pattern to help you – print this off and use it as a template for your test pieces! You can then store these in a folder with your notes so that you have a mini catalogue to refer back to later on. 🙂
Cut your test piece out on grain. Be sure to cut the piece AWAY from the fabric edge, as the edge is known to roll and stretch lots!
Stretch and Recovery
If you take your 10cm / 4” piece of fabric and pin one side down to the left of the template, you can then ‘stretch’ the fabric by pulling the opposite end and seeing how it behaves.
• For a stable knit, you should be able to stretch it to 12.5cm / 5”. This is a 25% stretch ratio.
• Knit fabrics that can stretch to 18cm / 7” are stretchy knits.
• If it stretches to over 25cm / 10” it is seriously stretchy and your pattern should be physically smaller than the body it is covering.
Another consideration is the stretch direction:
- Some knit fabrics are 2 way stretch meaning that it can stretch in two directions
- Then there are 4 way knit fabrics which are knits that can be stretched in both directions but also bounces back to it’s original measurements when let go.
If you want to drape your own blocks using knit fabrics, it is advised to use a stable knit as the draping fabric. This will give you the most accurate pattern to work from.
The last thing to consider is how the fabric reacts after being stretched out. This is referred to as stretch memory. If a knit fabric has a super duper amazing memory it will return to exactly as it was before you stretched it out. If a knit fabric has a crappy memory – a bit like me when I have to remember something not fashion related 😉 – it will appear slightly stretched and saggy.
This is why some tops when worn appear to become baggier and baggier when worn. They have no stretch memory.
Two Methods For Creating Your Own Stretch Fabric Patterns
• Stand modelling
• Flat pattern drafting
Using the stand as your guide, you drape your chosen knit fabrics on the model. You must be careful not to stretch the fabric TOO much. I find it easier to flat pattern cut when using knit fabrics.
Flat Pattern drafting:
This is when you use your body’s measurements to draft your own personal block. You will need to be careful to factor in the stretch properties of your chosen fabric.
I’m going to be starting the pattern making posts in the next two weeks and will definitely be showing you how to drape with knit fabrics! So be sure to stay tuned! 🙂
Cutting knit fabrics
As always, be sure to wash your fabric first to make sure it won’t shrink after cutting, sewing and washing.
Pin your patterns carefully to the knit fabric and make sure not to stretch the fabric as you do so.
Make sure pins that you use are sharp. Knit fabrics are made from one long yarn, so you don’t want to get a snag!
Sewing Knit fabrics
Usually, you’d want to use a serger / overlocker on knit fabrics. This is a machine that encloses the seam edge so that it cannot unravel. For those sewing beginners who don’t own an overlocker, you could use the zigzag stitch on a regular domestic sewing machine.
When using a serger / overlocker, remember that the seam allowance is 7mm. Anything more than this will either be trimmed off or your garment will be bigger than anticipated.
Always use a ball point needle when sewing tightly twisted knit fabrics.
Use a sharp needle when sewing loosely twisted knit fabrics.
It really does make all the difference.
It is also important that you use the right sized needle.
• A too small needle will cut through the fibres
• A too big needle will leave big holes.
Try to use stretchy thread if you are sewing knit fabrics. As they are knitted, they have more stretch. This means you need a thread that will work and stretch WITH the fabric rather than restrict and restrain it.
5 Final Sewing With Knit Tips
- Use knitted interfacings on knit fabrics
- Use a woven stay tape cut to size on areas that need restraining
- Cut knitted bias strips on the maximum stretch of the fabric
- Only use nylon zippers on knitted fabrics
- Interline your fabrics when adding button holes