I use them on pretty much everything that needs a zip. If I'm making a dress or a skirt that needs a zip, I always make it a lapped one (even if the instructions say otherwise), not least because I seem to always have lots of luck finding vintage or standard zips in secondhand stores, resulting in a rather large pile of them.
Inserting a lapped zip means you don't have to go out especially to buy an invisible zip if all you have is a standard zip. You can make any pattern that has a 1.5cm (5/8in) seam allowance fit a lapped zip, but that is probably the minimum, any less and there wouldn't be enough to make the 'lap' that covers the zip itself.
Lapped zips are actually really easy to insert accurately and cleanly - so let me show you, I promise it's not scary!
First off, we have to prepare our garment to insert our zip - this is the step that makes putting in a zip that is accurate so much easier. Ever had your waist lines not match up at the back when putting in a zip? Well, no more...
Preparing to insert your lapped zip
1. Finish off the back seam raw edges being really careful not to remove any seam allowance.
2. Right sides together, line up the edges of your centre back seam, ensuring the waist seam and the top of the bodice line up - pin in place.
3. For accurate zip placement on the Felicity dress, measure 1cm (3/8in) down from the top of he back bodice. Place the top of the zip (the metal bit) at that point and locate where the bottom of the zip ends (the other metal bit) on the skirt. Place a marker pin here - indicated by the arrow below.
Once you've reached that pin, change your stitch length to the standard length you use when sewing permanent seams. Sew a few stitches, then back-tack back to the marker pin, then continue all the way down to the bottom of the skirt. Back-tack at the end.
5. Press your back seam open.
Inserting the Zip
1. Open up your zip and face down, place the right-hand side of the zipper teeth onto the right-hand side of the centre back seam seam allowance, lining up the teeth exactly with the basted back seam. Line up the bottom of the zip where your basting stitch ends.
2. Baste the right-hand side of the zip to the back seam allowance only. You'll want to ensure that you are stitching as close to the seam allowance finished edge as possible, while still attaching your zip.
3. Do your zip up. Take your basted zip and pinch the seam allowance in half so that the teeth of the zip fold out and are now facing you the right way.
Pin down the small length of fabric that is running up the side of the zip, in between the right side of the zip teeth and the basted centre back seam. This will only be about 3mm (1/8in) wide.
4. Using your zipper foot, stitch down the 3mm length of fabric you pinned to the zip using a standard straight stitch and making sure to only stitch the seam allowance and not the right side of the garment.
5. Once the first side of your zip has been attached, pin the loose side of the zip, facing down, to the other side of the centre back seam allowance, through all layers of fabric to the outside of the back of the dress. Ensure the zip is flat.
6. Stitch the other side of your zip down starting from the top, through all layers, pivoting 90degrees at the bottom of the zip and finishing at the centre back seam.
Note - I prefer to stitch my zip down with the inside facing me. This way, I can pick a spot on the zip to follow to ensure I stitch a straight line. If you prefer to stitch with the right side up, you'll have to eyeball your seam a bit more to make sure you aren't sewing over your zip, or too close to it.
7. At the bottom of your zip, do not back tack, instead, leave a long tail. Once you've finished your zip, pull your threads to the underside and knot.
8. Gently press your seam and unpick your basting stitches on the right side to reveal your lapped zip.
Not as scary as you thought now was it?
If you have any questions, please let me know and I'll do my best to answer them. Otherwise, the Felicity Sew Along will continue next Monday when we talk about how to insert invisible zips.