Concealed (invisible) Zip Insertion

Be sure to choose the correct weight of zip for the garment and use the correct zipper foot. A minimum of 2cm seam allowance is advisable for a zip insertion.

The zipper is inserted into the seam. The zip should be approximately 2cm longer that the opening allowance to allow for a clean turn through at the bottom.

1. Stitch the 2cm seam below the zip opening.  Press open and continue to lightly press a 2cm seam allowance on the zip opening.  This will be used as a guide line when inserting the zip. Overlock or zig-zag the edges.
2. Open the zip and align the tape of the zip to the top of the opening with the roll of the zip (next to the teeth) resting on the guide line, edge of zip is in the same direction as the edge of the garment.  The side of the zip being inserted is right side face down! (right side to right side).  This will cause the fabric to roll into a seam when the zip is folded back into the correct position after stitching.
3. Slip the curl of the zipper teeth in the groove of the appropriate side of the zipper foot.  (this will depend upon the style of zipper foot being used)  The stitching must be close enough to the teeth to allow the zipper to close.  Too far away and it will cause ‘grinning’  when the zipper is closed.
4. Stitch to the bottom of the opening as fas as possible and back stitch.  Close the zip to test that you have stitched the correct distance from the teeth. 
5. Align the opposite side of the zip to the opening with the roll resting on the guideline.  Re-open the zip.  Stitch to the bottom as far as is comfortably possible.  
6. Lift the puller into the gap between the zip teeth (your extra 2cm length).  Carefully pull up the puller through the gap between the garment and the zipper.
7. If the zip is inserted correctly, there will be one continuous seam with no puckers at the bottom of the zip.    A very sight pucker can be disguised with a hand stitch on the wrong side of the garment.
8. For long openings use a chalk or thread notches to keep the left and right side aligned.  For stretch fabrics and bias cuts garments use a narrow strip of iron-on interlining on the garment to reach say 3mm beyond the seam line.  This will stabalise the seam.

Credits
Producing/Demonstrating: Claudette Davis-Bonnick
Filming: Nick Sargent
Editing: Kenny MacLeod
Stills: Nick Sargent, Junior Bonnick
Thanks to: Oliver Furlong, Media Services, CLIP CETL "Making a Difference" funding at the London College of Fashion