To further reduce the possibility of fabric puckering at the seam, maintain slight tension or back pressure (Fig 5) on the fabric as it feeds through the rollers. If too much tension is applied to the fabric, it will tend to stretch the fabric and tape. This results in shrinking of the tape as it cools.
F. Normally, the tape is applied to the inside (coated) surface of the fabric in such a manner as to cover the stitching and extend at least 114″ (6 cm) beyond each side of the seam.
G. If the seam is bulky (3 or more layers or heavy fabric), a grooved lower roller is recommended. This allows the seam to be depressed and presents the flattest possible surface to the tape. If your machine is equipped with a heated upper roller, heat should be reduced to the lowest possible setting. Adhesive will always be attracted towards the heat which would be counterproductive.
H. The correct position of the hot air nozzle is critical. Incorrect positioning can result in improper sealing, scorching fabric or “burn-through” of the tape.
I. Check to be certain the nozzle and rollers are the proper width for the tape being applied. Both nozzle and rollers should be at least 118″ (3 mm) wider than the tape to ensure effective sealing. The nozzle should also be centered left to right to cover the width of the tape