Recently I received an email from Carole (to which I did reply, Carole, but it bounced. Sorry!):
Thanks for letting us see the finished dress. We have been involved from the start and what fun! Making the leotards sounds difficult. I’m not sure I know how to sew on stretchy fabric. I have some cotton knit Tees that I would like to change the necklines. Any secrets?
Well Carole, sewing with stretch fabrics is not all that difficult, and you don’t need an overlocker/serger to be able to do it successfully. I don’t own one, and I expect that I never will!
The important thing about stretch fabric is that it stretches! (amazing!) This means that if you just feed it through the sewing machine as you would normally, the part where it has been machine sewn will no longer stretch. This means that when you wear the garment or use the thing (whatever it is that you are sewing) the sewing will break to allow it to stretch, which is not what you want!
To counteract this, when working with a normal straight stitch, you stretch the fabric as you sew. I normally put the seam in the machine, sew one or two stitches, then hang onto the thread tails coming out the back, and pull the part of the seam I am about to feed in, and stretch them apart. It means that as I sew, it sews the whole distance of the stretched fabric. When the seam comes back to rest (when I remove my self-imposed stretch) the stitches will look shorter, but the seam will still be able to be stretched.
When working with a zigzag stitch you don’t need to stretch, as the extra width of a zigzag can stretch out to become length. But sometimes you don’t want a seam or overstitching in zigzag – which is where the technique of stretching as you stitch with a straight stitch comes in instead.
For the first step for each seam, you use a large zigzag on the edge of the fabric, to enclose the raw edge. You do this without stretching.
For the second step for the seam, you use a straight stitch using the correct seam allowance away from the edge of the fabric. This time you DO stretch as you sew.
I used a similar technique for my little red dress in that I stretched each seam as I sewed them, including the darts and tucks. When the side seams were sewn, I trimmed them back to 6mm and worked a wide zigzag over the edge. It worked just fine, and there’s been no problem with seams breaking etc.
For those of you who have never sewn stretchy fabric before, I hope this gives you a place to start. If you’ve got more questions, please ask, and I just may be able to answer them. If not, I’m sure I’ll find someone who does know the answer!