Whether you're sewing superhero costumes or dance leotards, sooner or later every costumer needs to sew stretchy knit fabric. The ideal tool for sewing knits is a serger or overlocker. Sergers are complex machines, and not everyone has the luxury of having one. Fortunately, you don’t need one to create a successful knit sewing project.
Knit fabrics have really come a long way in the past few years. We can now appreciate having cotton jersey and microfiber fabrics that are so soft and cozy. Who wouldn’t want to sew them right? The reason knits are tricky is that as they stretch, the seam needs to stretch, too. If you sew the seam using a regular stitch, the thread will break and your seam will fail. There is a fix, though. Don't worry, it’s not hard; it’s all in the tools you use.
Having the right kind of needle is crucial for this task. You need to have a ball point needle in order to sew knit fabrics, as they are specifically made for the task. Even if you usually use a universal needle, switching to a ball point is the right way to go. The stitch quality is much higher than that of a universal needle. The universal needles can cause skips in stitches or even holes in your fabric. This is a simple switch that makes a big difference.
It is also extremely important that you use the correct stitch setting on your machine. Seams often fail due to the use of a straight stitch, which does NOT allow the fabric to stretch correctly.
At some point, the thread will become too tight and snap. Guess what that means. Right, you have a giant hole in your seam. So what can you do? You have to use a stitch that stretches. A zig-zag stitch works as a nice solution. It is strong and stretchy because the stitch is varied a bit. You can also use a “tricot stitch” which looks like a broken zig-zag on a machine stitch chart.
However, if you have a combo embroidery/sewing machine like the Janome Memory Craft, you can use decorative stitches when working with your knit fabrics, as well as other fabrics. There will probably be a huge variety of stitches to choose from, which is a nice luxury when you’re working with things like elastics because they can look very nice. This makes all the difference, especially if you’re working on a waist line of shorts, leggings, etc. Do a few trial runs first using scrap fabric so you can see which stitches are the most efficient and look the nicest and most appealing to you.
An even feed walking foot make such a difference when you’re working with these fabrics. It is a huge help when you want to have a fabric run smoothly and at an even pace as it goes through the sewing machine. This is useful also because many stretch fabrics (such as spandex) are slippery and can be a hassle when you’re trying to keep it from moving all over the place. If a walking foot didn't come with your machine, you can buy one fairly cheap at your local sewing store or on Amazon.
With the right stitch, needle and a walking foot, you can whip up any spandex-y stretch costume you like without a serger. So, don't fear the Superman suits any longer. (You may even have to make your own "Super Costumer" secret identity outfit. Just remember the wise words of Edna Mode--No capes!)