Elastic
Definition
Elastic is a stretchy band, cord or thread made with rubber or spandex fibers, used in waistbands, cuffs, necklines and shirring to gather fabric and hold it close.
Elastic comes in several constructions, and the right one makes a waistband comfortable instead of twisting or digging in.
| Type | Character | Best for |
|---|---|---|
| Braided | Narrows when stretched, ridged along its length | Casings and sleeves; not for sewing through |
| Knitted | Soft, keeps its width when stretched | Sewing directly to fabric, lightweight garments |
| Woven (non-roll) | Firm, resists rolling, keeps its width | Waistbands of trousers and skirts |
| Clear | Thin, transparent polyurethane | Stabilizing shoulder seams and necklines in knits |
| Elastic thread | Fine, wrapped thread | Shirring, wound on the bobbin |
Widths run from 3 mm (1/8 in) for sleeves to 5 cm (2 in) for wide waistbands; 2.5 to 4 cm (1 to 1 1/2 in) is typical for a pull-on waist.
Elastic is cut shorter than the body measurement it goes around, so it grips. For a waist, a common starting point is about 90% of the waist measurement: a little longer for firm elastic, shorter for soft, very stretchy elastic. Try it around your body, lightly stretched, before joining the ends, then overlap them by 2 cm (3/4 in) and zigzag them together.
Sewly's sewing guide gives the elastic length for patterns with an elastic waist or cuffs. To size it yourself, use the elastic length calculator, and see casing and shirring.