Spandex refers to a type of elastic thread used in conjunction with other fibres to produce a very stretchy type of fabric. The thread is made from polyurethane and woven into fabric. Its use has become so ubiquitous that spandex is now used to refer to the fabric itself. The larger the percentage of spandex in a fabric the greater amount of stretch the fabric has. Swimsuits and dance wear will often be up to 90 per cent spandex.
Pin hems up or edges together.
Thread a sewing machine or needle with polyester, or polyester cotton coated thread. Pure cotton thread should be avoided as it will break on stretching. If you are sewing with a sewing machine, using a texture nylon thread in the bobbin will provide more stretch to seams and hems.
Sew hems and seams using two rows of stitches, one on the seam line, and one 1/4 inch nearer to the edge of the fabric. Use medium-size stitches, straight or zigzag (or one of each) to create the row.
Prepare the cloth by washing on a cool wash, at -1.11 degrees C and allowing it to dry. This should be done at least twice to make sure the fabric has shrunk before it is worked on. Use a clear elastic tape at seams that will be given more pressure, such as shoulder joins, to strengthen them. Cut a straight edge to the fabric, if needed, before cutting patterns out. Achieve this by folding along the grain, the direction of weave with most stretch, and checking that the edges folded together are at right angles to the fold and that they meet. Practice on small scrap pieces first to check that the tension of stitches doesn't cause any rucking.
Do not bleach, use a hot iron, or wash spandex at a high temperature.