After I posted my Silvia Dress a few of you lovely people requested a tutorial for the method I used to insert the side seam zip (which I am still so proud of!). It was my very first time inserting a zip in that fashion (where the seam is closed both above and below the zip) so I don't feel like quite enough of an expert to be volunteering up my slightly 'trial and error' method as a guideline for others to follow! However, I have picked up quite a few invisible zip tips from a variety of sources over the time I have been sewing and I think making use of these definitely made that tricky insertion more successful. I thought I'd share with you some of my favourites and those which I think have made the biggest difference in terms of accuracy and first time success.
- Make the very first thing you do to press the zipper teeth away from the tape. Be gentle and use a cool iron as you don't want to melt the plastic teeth! This is one of the first tips I picked up (from some By Hand London pattern instructions) and I've been doing it ever since. On a couple of occasions I've forgotten and could really notice the difference. It means you can stitch really close in to the teeth which really affects just how invisible that zip is.
- The next preparation step is to add a strip of fusible interfacing to the seam allowances where you are going to insert the zip. I first saw this mentioned in Lladybird's fantastic invisible zip tutorial and it really has changed how accurately my zips go in first time. You just need a slim strip the length of your zip on each side. It prevents your fashion fabric from stretching out as you pin or sew in your zip which means you don't end up with one centre back mysteriously longer than another and some serious misalignment going on.
- One of the most notoriously difficult things about inserting a zip is getting seam lines to match up, usually at the waist or waistband. The instructions for Sew Over It's Betty Dress gave me a great tip to help solve this one. You sew in one side of the zip as usual. Then, before you pin or sew in the second side, do up the zip. Make a tiny snip or draw a tiny mark on free side of the zip tape at exactly the point where the waistband (or any other seam lines intersecting the zip) meet the centre. Undo the zip and pin then sew it in, making sure that mark or snip you made lines up exactly with the seam line on the second side.
- Another Lauren tip which has made a subtle yet significant difference to the alignment of my zips is to sew both sides in the same direction. It's again to do with the stretching out of fabric and things shifting ever so slightly as you sew. You may have pinned the second side of that zip in perfectly but, especially if it's a long zip, the pressure of the foot and the differing feeds of the fabric and the zip may cause things to move enough to be out by just a couple of millimetres. If you sew the right side from top to bottom, make sure the left side is sewn top to bottom too.
- The fifth and final tip is something I only really do if I'm working with a really tricky fabric or on a super special project. Sally includes some great instructions for invisible zips in her Capital Chic patterns which involve basting the zip opening closed before insertion. This means you've basically got not chance of misaligned intersecting seams (unless you've basted them wonky to start with!) and results in a perfectly neat and today finish. It does add on a bit of time but is definitely worth it if you're working with a fabric which really won't hold up to any unpicking or multiple layers such as lace and and underlining.