: Pulling or stretching the fabric while sewing the zipper in can cause it to "wave" once released.
: Applying a strip of lightweight iron-on stabilizer or stay tape to the seam before sewing helps the fabric behave more like a woven material. bulve.zip
: High heat from a dryer can cause the cotton tape around a zipper to shrink while the rest of the garment does not, leading to a puckered effect. Fixes and Prevention: : Pulling or stretching the fabric while sewing
: Shaping the center back seam of a pattern to match the body's curve rather than using a straight line. bulve.zip