Elastic is comprised of a material such as rubber or spandex that is then bound within another material such as cotton or nylon. The flexible nature of the rubber or spandex material within elastic make it stretchable. The varying types of rubber or spandex used in elastic make the elastic more or less stretchable. Depending upon the material casing around the rubber or spandex, the elastic may easily stretch. When needing to stretch elastic for a craft or project, you can either sew the elastic and stretch it while sewing or apply heat while stretching the elastic.
Cut the elastic eight to 10 per cent shorter than length required for the clothing or project. While sewing, you stretch the elastic to create the give and pull desired of the material. For example, if the material that the elastic is being sewn to is 20 inches long, cut the elastic at 18.4 inches.
Sew elastic to material using a zigzag stitch and ballpoint needle. Gather the material to the elastic while sewing to create a natural stretching effect. You will need to slightly pull the elastic while stitching to hold the stretch of the elastic.
Stretch the elastic as you sew it to the material. The zigzag stitching will keep the stretched elastic bonded to the material and stretched after the sewing is completed.
Heat the iron to the hottest heat setting and do not use steam.
Tack down one end of the elastic to an ironing board using the pushpins. Use several pushpins to ensure the elastic does not pull away from the ironing board.
Lay the wash cloth over the elastic for protection from damage by the iron's heat.
Iron the elastic while pulling and stretching it. The heat from the iron will break down the elasticity of the material and create a permanent stretch of the elastic.
When ironing with a high heat setting, use proper safety precautions to prevent burns.