How to Sew with Sweater Knits
What are Sweater Knits?
Sweater knits is a term that is used to describe a group of fabrics that are used to sew sweaters. They are easily recognised as they have a textured and fuzzy surface. They tend to have the look of a hand knitted jumpers, but the fabrics are made on industrial machines rather than by hand. This means you can sew a cosy cardigan in the fraction of the time it would take for you to knit one from scratch.
There are two different types of sweater knits, open knits and dense knits. Open knits are stretchy, quite loosely knit and have a lacy look. Some mimic the look of a crochet sweater. Dense knits tend to be bulky, tightly knit and have limited stretch. The type of knit you have will determine how you sew with it.
All knit fabrics are made by interlooping threads or yarn i.e pulling one loop of yarn through another loop of yarn. However, sweater knits are made out of thicker textured yarns compared to other knits such as jersey. Sweater knits can be made from a variety of different fibres, both natural and manufactured, such as cotton, polyester, acrylic, rayon, viscose, linen, wool, silk and blends of different fibre contents. Any print or colour in the fabric tends to come from the yarns themselves rather than being printed onto the surface.
Below there are a number of tips on how to sew with this type of fabric. It doesn’t just have to be used for jumpers or cardigans, why not try a skirt or a dress. Have a look at the AW17 fashion week trends or my Balmain inspired dress for some inspiration! Make it: Sew a Balmain Inspired Knit Dress
Tips for sewing sweater knits?
Choosing a pattern
When looking for a pattern you generally want to find something that is fairly simple. Anything that has lots of pleating and gathering with get very bulky. You also want to pick something that doesn’t have too many seams, as this means you can focus on the texture, pattern and colouring of the fabric. Some companies do sell patterns that are specifically designed for sweater knits. However, if you have a stretchy fabric you can use any pattern designed for jersey knits. On the other hand, if you have a more sturdy fabric you could use a pattern designed for woven materials. Just make sure your fabric has the required amount of stretch for the garment you want to make, you don’t want to make a jumper that you can’t stretch over your head!
Make sure you prewash your fabric before any cutting or sewing. This should be done regardless of the fabric you are using.
- You should prewash the fabric in the same way that you plan to wash the finished garment.
- Unless the manufacturer says otherwise, wash this type of fabric by hand and avoid using too much heat and agitation.
- Lay the material flat to dry as hanging may distort the shape. • Handwashing is definitely the best thing to do if your fabric has wool in it.
- To hand wash fill a bath with warm soapy water at approximately 30˚C. I use a meat thermometer to help judge the temperature. Lay the garment/fabric flat and allow it to soak. Do not agitate, squeeze or rub vigorously. To remove the soapy water fill the bath with fresh water and gently squeeze out the suds.
If you are using a loose or lacy knit that looks like it is going to fray and unravel easily then you should consider extending your seam allowance. This means you will have plenty of room to cut away the frayed areas and finish your edges. Some patterns designed for knits only have a 3/8 inch SA, so depending on how loose the knit is consider increasing it to 5/8 inch. Additionally, if you sew too close to the edge there is a chance the sewing machine will chew up your fabric and nobody wants that!
To make your life easier when cutting out your fabric pieces, hold the fabric still using pattern weights and cut around the pattern edge with a rotary cutter. This will result in a lot less distortion of the fabric compared to when using scissors.
Pinning your fabric
To prevent the fabric from piercing I swapped my regular pins for ball point pins.
Marking Up your Fabric
You should not mark your fabric by snipping notches in the seam line. This is because these notches are hard to see and the fabric can stretch and unravel. Other methods of transferring markings to your fabric include using chalk, tailors tacks, marking with a pin or cutting a small triangle that sticks outwards.
When cutting and sewing handle your fabric with care. When the raw edges are not finished they can be prone to fraying. Additionally, when the edges are not secured in a seam they can stretch easily and distort the shape of the fabric piece. A stretched out wonky seam could ruin the garment!
- Whenever you sew a knit or stretchy fabric you should use a ball point needle. This is because when the ball point tip penetrates the fabric the rounded end pushes apart the fibres and goes between them rather than cutting through them. These will be available at any sewing shop.
- The size of the needle you use depends on the weight of your fabric. If you are using a fine delicate knit consider using a 70/11. However, for a dense heavy knit use a 90/14.
When I sewed my sweater knit I used a walking foot. It is really useful as it stops layers from slipping and prevents the fabric from stretching as you sew.
A bulky, dense knit that doesn’t have much stretch can be treated as if it is a woven fabric. Just sew using a standard straight stitch and finish the edges.
If you have an open or loose knit that stretches then you must sew with a stitch that stretches. If you have an overlocker you could use that. However, if you do not you could sew using a narrow zigzag stitch or any other stretch stitch option available on your sewing machine. You could also sew with a double needle. You will still need to finish your edges afterwards.
To make sure you get a nice looking finished garment you need to avoid stretching the material as you sew or else you will get wavy seams.
- Feed the fabric through the machine without stretching it by holding it up in front of the machine, this means the feed dogs don’t have to pull it through.
- Never ever pull the fabric through from behind the presser foot.
- Make sure the fabric on the left and right side of the foot are moving at the same speed.
Reduce the pressure foot tension.
- Place a piece of tissue paper under material to help it feed more easily. Although, it may be awkward to remove the paper at the end.
Any seams that you think will be prone to stretching out of shape, such as the shoulder seams, should be stabilised. One way of doing this is with clear elastic:
- Cut a piece of elastic that is longer than the length of your seam.
- Place the it on top of your fabric distributing the excess at either end of the seam. You want to avoid contact between the elastic and the feed dogs.
- Sew your seam, stitching through the clear elastic. You want to sew the elastic together with the fabric as if they are one.
- Ensure you do not stretch the elastic as you sew it.
- Once the seam is finished you can cut away the excess.
- Alternatively, you could use stretch mesh or a strip of cotton jersey cut on the lengthwise grain to stabilise the seam.
You do not need to do this if you are using a very stable knit.
Finish the Edges
If you have a sweater knit that looks like it will unravel easily it is vital that you finish your seams. However, even if the knit doesn’t look like it will fray it may be nice to do so anyway, as it creates a tidier and neater finish on the inside of your garment. You can do this by using an overlocker if you have one. If not just sew another row of zigzag stitches along the raw edge. You could also consider using bias binding.
To reduce the bulk at your seams you could also grade the seam allowance.
I would recommend hemming with a double needle. It creates 2 parallel rows of stitching that allows the hem to stretch when worn. You could use a zig zag stitch but the twin needle hem looks much neater. For how to prevent wavy seams perhaps have a look at http://www.made-by-rae.com/2012/02/hemming-knits-6-ways-to-beat-those-pesky-puckers/
When working with sweater knits pressing should be minimised. This is because you don’t want to flatten the texture with heat and steam. When using a textured knit just apply the tip of the iron to the seam. Try not to distort the fabric whilst you press it as it may stay stretched out.
If you are using a synthetic fabric you have to be careful as you don’t want the fabric to melt. Try hovering the iron an inch over the fabric and use the steam function to relax the seams. As with everything try practicing on a scrap first.
If you noticed your seams or hems have stretched out of shape consider using steam to relax them back into place.
As I would advise before you start any new sewing project, test your stitches on a scrap rectangle of the fabric. This means you can check the tension, stitch length etc. It also means you can practice handling the fabric to make sure you are not stretching it as you feed it through the machine.
You can also use your test piece of fabric to see how bulky it is once you have folded it, this will inform whether you turn over your hem once or twice. Also, you can test your fabric to see how difficult it is to unravel, which will help you determine whether you need to finish the edges.
One thing to be aware of is that sweater knit fabrics like to leave fluff behind. Therefore, make sure you give your sewing machine a proper clean once you have finished. Dust and lint gathering in the bobbin area could cause you issues later.
Make sure you take your time and don’t rush. This will make sure you are doing the right thing at the right time and reduce the amount of errors. Hopefully, you can relax and enjoy the process rather than getting stressed!
See how I have used sweater knits in: