Prewash the Spandex fabric in cold water, followed by line drying, before using it to sew. One thing to keep in mind as you stitch is that intense heat can harm spandex fibres, so use caution when pressing, etc. You must choose your needle and thread according to the fabric's weave because most Spandex materials are blends. Change the needle to a heavier (90/14) or a lighter one depending on the fabric's weight. If the fabric is a cotton-spandex blend, sew it like a woven fabric; if the fabric is thicker, like denim-lycra, use a strong needle designed for sewing denim.
To stitch these materials, use polyester or cotton/polyester thread. Although it is a stretchy fabric, the majority of fabrics only contain 10%, etc. of spandex, so you can sew regular seams without the need for zigzag stitching. However, if the fabric is extremely stretchy, use a close and small zigzag stitch to sew the seams. This will ensure that the seam stitching does not break later. Nevertheless, stretch the cloth while you sew to prevent puckering and stitch breakage.
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