Spandex stretches four ways. This gives it its practicality for active wear; however, it is also what makes it somewhat tricky to sew. Here are some tips to help you sew Spandex with ease:
A standard sewing machine needle, size 11 or 14 can work well for Spandex. If your machine accepts them, you might also want to try a stretch needle, which is specially designed to prevent skipped stitches while sewing Spandex. Again use size 11 or 14.
Most machines have several stretch stitches. Before you begin sewing your Spandex garment, use a scrape of the Spandex to test out your stitches. Adjust the stitch length and tension, so that the stitches look right and the fabric does not pucker.
Puckering is a problem when sewing Spandex. Remember to keep the fabric slightly stretched as you guide it under the needle, but never pull it.
Spandex has a tendency to pull down into the feed dogs. You may want to change your machine’s needle plate to a straight stitch needle plate when sewing delicate fabrics such as Spandex. Straight stitch needle plates feature a small needle hole and are designed to prevent fabrics from pulling down into them. If you don’t have a straight stitch needle plate or your machine doesn’t accept them, placing small pieces of tape at the front and back of the needle hole in your machine’s plate to decrease its size can be helpful.
See spandex in action in How to Make an Infinity Dress.