How to… Sew stretch fabrics
New dressmakers are often wary about sewing with stretchy fabrics to start off with but if you choose a stable jersey knit fabric and follow these top tips it can be really quick and fun even for absolute beginners.
Sewing stretchy fabrics requires a slightly different approach to sewing woven fabrics so here we’ll get into how to handle your fabric, from the moment you get it out of the shopping bag to the sewing machine!
Prepping and pinning
First WASH YOUR FABRIC! Stretchy fabrics – especially those with a high cotton content – can shrink quite a bit so pop your fabric in the wash as soon as you get home from the shop to pre-shrink it.
When laying your fabric out on the table gently smooth and pat out any wrinkles rather than pulling the fabric, this will make it easier to get it to lie flat.
Stretchy fabrics do have a tendency to roll so pinning with your pins perpendicular to the seams can help to hold them flat until you have sewn them. Learn how to tame super rolly edges here.
Alternatively you can use quilting clips to help hold the seams together. These are particularly useful when using tightly knitted or very fine jerseys where pins may create a hole.
You will need nice sharp scissors when cutting jersey fabrics so that you slice through the fabric rather than chomping at it. Stretchy fabric does not like blunt blades!
Finally, in preparation, you need to change your machine needle to a jersey or “ball point” needle. Find out more about how to choose the right needle for your fabric.
This needle has a slightly rounded tip which will wiggle through the knit of the jersey rather than piercing it which could potentially create holes and ladders.
Sewing knit fabric
You need to use a stretch stitch on your machine. This might be a very narrow zigzag stitch or what we call the “lightning stitch” on Brother machines:
I always like to extend the stitch length on this stitch as I find this stops the stitches getting bunched up. Do you have a play with the stitch settings to find the best option for your machine.
Ok, let’s sew those seams!
Start stitching about half a centimetre in from the top edge of your fabric. This will prevent the fabric being pulled down into the feed dogs of the machine.
If your fabric is really lightweight and you do find it is getting pulled down into the feed dogs you can use a little bit of tissue paper underneath the first 5cm of your seam to help stop this. Just placed the tissue between the feed dogs and your fabric as you feed it through under the machine foot.
When using the lighting stitch you do not need to backstitch, in fact the settings on most machines will not allow you to backstitch. However, if using a narrow zigzag you can do some back stitching to reinforce your stitching.
The seam allowances on most of our patterns are 1.5 cm (5/8ths inch). Do be aware that when using the lightning stitch or a zig zag stitch on most machines your needle will be in the centre position so you need to adjust where you position the edge of your fabric to get the seam allowance correct.
The alternative is to use an overlocker to join all of your seams.
Edge Finishing
The edges of knitted fabics will usually not fray so you do not need to finish the edges. If however, you wish to or you are making your garment in a fabric which does fray, you can finish your raw edges with one of the following methods:
Overlocking: Use an overlocker machine to finish the edges of the seams, sewing them together after constructing your garment but before doing any topstitching - you can also use an overlocker to construct your garments but make sure you are trimming off 1cm to achieve the correct seam allowance.
Overcasting: Some machines have a special foot to use with this stitch which looks a bit like mountains and valleys. Line up the edges of the fabric with the gap in the foot and use the protruding leg to guide the fabric. This will help you to sew over the deges and stop them from rolling.
Zigzag stitch: Set your machine to a medium length and wide zigzag to reduce rolling or puckering of the seams. Stitch close to the edge of the fabric.
We will prompt you when to finish your edges in our pattern instructions.
Hemming and topstitching
First, press the seam or hem allowance and pin or clip to hold in place. Then stitch using one of these methods:
3 step zig zag stitch: This stitch is ideal for jersey hems as it stretches with wear and will hold rolly raw edges in place. We use a stitch setting of 2mm length and 3.5mm width. Stitch on the wrong side of the fabric so that the zig zag stitches run along or over the raw edge.
Twin needle stitch: Fit your machine with a twin needle and second thread spool following your machine's instruction manual. Use a straight stitch. Twin needle stitching is more tricky as you have to stitch on the right side of the fabric. This is made much easier by firmly pressing the seam allowances.
The bobbin thread creates a zigzag effect on the underside which, if possitioned well, will cover the raw edges of the hem so try to get this as precise as possible. You may wish to draw your stitching line on the right side of the fabric with chalk or erasable pen.
Low quality threads can create skipped stitches when using a twin needle, so use quality threads when twin needling your hems. We love Mettler Seralon thread for all general sewing and use this on our machines at home and in the Crafty Sew&So Workshop.
