How to Sew an Invisible Zip – Step by Step

An invisible zip is sewn before the rest of the seam is closed: the coil is unrolled with a cool iron, the zip is placed face to face with the right side of the fabric along the seam line and sewn with an invisible zipper foot from the top edge down to the slider. Then the second side is sewn, the zip is closed and the seam below it is finished with an ordinary zipper foot. From the right side only the pull tab remains visible.

How to sew an invisible zip – preparation

An invisible (concealed) zip looks best when the stitching runs as close as possible to the coil. To achieve this, preparation is just as important as the sewing itself.

What you need

• an invisible zip slightly longer than the opening (by at least 2–3 cm);
• an invisible zipper foot and an ordinary zipper foot;
• thread matching the fabric;
• pins or clips, chalk;
• thin fusible stay tape for the seam allowances;
• an iron.

Preparing the fabric

1. Reinforce the seam allowances. Fuse a narrow stay tape to the wrong side of both allowances in the zip area. It stops the fabric from stretching and puckering, especially with knits, satin and chiffon.
2. Finish the edges of the allowances with an overlocker or zigzag before sewing the zip.
3. Mark the seam line and the point where the opening will end.
4. Do not sew the seam below the zip in advance. With an invisible zip, the zip is inserted first and the seam afterwards.

Preparing the zip

Open the zip and, with a cool iron (synthetic setting, no steam directly on the coil), unroll the coil towards the tape so that the groove between the teeth and the tape becomes visible. This lets the needle get closer and makes the zip truly invisible. Do not overheat – the nylon coil can deform.

Inserting an invisible zip step by step

1. Position the first side. Lay the open zip face down on the right side of the fabric, with the coil exactly on the seam line and the tape towards the edge of the allowance. The top stop is about 3–5 mm below the line of the top seam (waistband or facing). Pin in place.
2. Fit the invisible zipper foot so that the unrolled coil sits in the groove to the right of the needle.
3. Sew from the top down until the foot touches the slider. Secure with a few backstitches. Do not try to sew right to the end – a small section will remain there, which is closed when finishing the seam.
4. Close the zip and mark the second side. Mark on the tape the levels of the horizontal seams and the waistband so that they match.
5. Open the zip and sew the second side in the same way, with the coil in the left groove of the foot.
6. Close the zip and check from the right side that it is invisible and that the levels match.
7. Finish the seam below the zip. Change to an ordinary zipper foot. Move the end of the tape aside and start the seam 1–2 mm above and slightly to the side of the last zip stitch, continuing down the seam line.
8. Secure the lower ends of the tape to the seam allowances with a few stitches so that they do not move.
9. Sew the facing or lining to the zip tape on the inside.

Inserting an invisible zip with a lining

On lined dresses and skirts, the zip tape is caught between the outer fabric and the lining. The cleanest result is achieved when the lining is sewn to the tape by machine, not by hand, and stays 3–4 mm from the coil so that the slider does not catch it. At the top, the facing is turned to the inside and covers the end of the zip.

Sewing an invisible zip with a standard foot

If you do not have a special foot, an invisible zip can also be sewn with an ordinary one-sided zipper foot. Unroll the coil with an iron and sew slowly, using your fingers to fold the coil away from the needle. The result is harder to achieve and the zip often remains partly visible. For series production and regular work, an invisible zipper foot is essential.

Invisible zips in knits and stretch fabrics

With knits, jersey and fabrics containing elastane, the seam around the zip easily stretches and becomes wavy. That is why stay tape on the allowances is mandatory here, not just recommended. Sew without stretching the fabric, ideally on a machine with differential feed or with reduced presser foot pressure. Check after each side that the tape and the fabric are the same length.

Which thread and stitch

Use polyester sewing thread matching the fabric and a medium stitch length. With very fine fabrics, shorten the stitch and use a finer needle (70 or 60) to avoid visible holes. The thread should match the fabric, not the zip – if the stitching shows, it will blend into the material. Suitable threads in a wide range of colours can be found in the sewing threads category.

Checking the finished zip

• From the right side neither the coil nor the tape is visible, only the pull tab.
• Seams, waistband and horizontal lines match on both sides.
• There is no bubble or puckering of the fabric at the bottom end.
• The slider runs smoothly up to the top stop without catching the lining.

Invisible zips wholesale from Polkom

Polkom is a manufacturer supplying invisible zips in various lengths and a large range of colours to garment factories, brands and ateliers, as well as original YKK invisible zips. We match the shade to a fabric sample. Send an inquiry with the lengths, colours and quantity – we will prepare samples.