Many people avoid working with jerseys altogether and wrongly assume you can only sew jerseys using a overlocker (serger), however with a little bit of experimenting and practice you’ll soon find jersey a very forgiving and versatile material!
In this blog post I will share with you the tricks that I have learnt over the years, running my handmade business.
While an overlocker is ideal for sewing jerseys, it can certainly also be done on a standard domestic machine. I found that using a simple zigzag stitch gives the best results. Just experiment with the stitch length and width making sure to open & check the seam, until you're happy with the result.
Whether using an overlocker or a standard machine, make sure you use a jersey, stretch or ballpoint needle. All have a rounded tips, pushing the fibres of the material aside rather than poking a hole through, which could cause laddering. Ballpoint needles are most suitable for heavier, sweatshirt type knits, stretch needles are best suited to highly elastic materials with spandex/elasthane/lycra such as swimwear, whereas jersey needles are best suited to (the clue is in the name) regular knit jerseys.
Make sure you DO NOT pull on your material while sewing, as this will cause those dreaded wavy seams. Other causes for wavy seams are to do with the settings of your machine. Familiarise yourself with it, read your manual and make sure you understand what it says. Even when you've read it before, read it through again from time to time, you'll be amazed!
If you're in the lucky possession of an overlocker, let's take a closer look at it. For the example below I've used a different colour for every thread, so that I can see exactly which thread goes where while I sew. And yes, you can (and should) definitely try this at home!
On an overlocker it's all about balance, especially with the looper threads. These are the threads that are wrapped around the fabric edge and are supposed to interlock just there, right on the edge. They work together- too much tension on one thread has a similar effect to too little tension on the other thread, and vice versa.
Below are 4 tests runs I did where I adjusted just one looper tension at a time. As you can see, too much tension on the upper thread or too little tension on the lower looper will both cause the interlocking of the threads to appear on the face of your work. Using too little tension on the upper thread or too much on the bottom, you'll find the interlocking on the reverse of your work.
If your tension is off and you want to fix it, just adjust one dial a little bit at a time, doing another test run after every change so you can check the result.
The needle tension is less obvious, but also a little less complicated. If you can see the stitches when you open the seam, chances are your left needle tension is too low. If tension is too high on either of your needles, your seam might appear uneven, or the thread may even break. Too little tension on the right needle and loops will appear on the reverse of your seam.
Many machines (both overlockers and standard sewing machines) also have a very useful feature called differential transport, this is super important when sewing knit fabrics. A setting of 1.5 is a good start but experiment with it. Do a little test every time you start a project, making sure you know the best setting both across and along fabric grain. When sewing along the grain I find I often need to increase the differential transport a little.
In addition to the differential transport, foot pressure can also be adjusted on some machines. This is useful when sewing very thin and stretchy materials. Reducing the foot pressure will help the machine to pull less on the material whilst sewing, helping prevent those pesky wavy seams again. Finding the right balance between differential feed and foot pressure can be a fine art with some fabrics!
Last but definitely not least, threads can make or break (literally!) a project. For a long time I didn't appreciate the importance of using the right threads. The trouble with using cheap threads particularly when sewing jerseys is that they break too easily when the seam is stretched. Overlocked seams allow some stretch, but often the material is stretchier than the seams, causing the threads to break.
It has taken me quite some time and experimentation to find the right combination of threads. I now use woolly nylon as one of my looper threads, ideally you'd probably use it for both looper threads but it's pretty pricey and I've found that if I combine the one woolly looper thread with Madeira Aerolock for the 3 other threads, my seams turn out bullet proof!
Before I finish this post, a little also needs to be said about hemming. I've decided to invest in a coverstitch machine, which is absolutely brilliant! But then I have the excuse that I "need" it for my business, which I appreciate is not the case for everyone. Also, it's actually not entirely true, as it is indeed possible to get picture perfect hems on a standard sewing machine. The answer is using iron-on hem tape and a twin needle. The tape is ironed on, keeping your hem neatly in place while you sew. The twin needle then sews a double row of stitching on the face, looking very professional indeed, while the looper thread zigzags between these rows on the reverse... Nice!
Now that you know all the ins & outs of sewing with jersey knit fabrics, why not try out one of my easy sewing patterns? https://babooshdesigns.com/collections/sewing-patterns
If you're quite new to sewing, the Leggy Pants baby or kids leggings are a really good place to start!