I know I know, even I don’t believe that statement – yet! It is gonna take a while for it to sink in that I’ve just set in two invisible zips that turned outperfectly, in the past 2 days.
Ok, so let’s write it all down so I don’t forget for next time, and on the off-chance I can help someone else.
1 Open up the zip and iron the coils flat. OK, so it says so in the instructions that come with it, but of course I had to work out the hard way this really made a difference. I use nylon heat setting which is warm enough to actually DO something but not so hot the zip melts. (Always a bonus!)
2 Stabilise the seam opening edge. I have learnt to do this especially on a curved edge, or if the fabric is a bit soft and flooffy (technical term). However, on a straight-grain seam opening in a reasonably sturdy fabric it doesn’t make much difference.
3 Neaten the seam edge, aka do whatever you need to stop it unravelling. (Let’s be honest about it. In my reality this means overlocking, not an exquisite hong-kong edging ;-P) I find it easier to do this now, rather than once the zip is set in.
4 “Key” the zip. (I think that is the right term, correct me if I am wrong) This step is the Master Step, I have discovered. The one that makes the rest of the setting in sooooo much easier. Attach the top of the zipper tape with a simple straight stitch, to the seam allowance, right where the zip starts. Do this on both sides of the zipper/seam allowances. In other words, line the zip up onto the garment exactly how it will go, then sew it down to the seam allowance at the top of the zip, on both sides; ie you actually sew the top of the zip in place, across the zipper tape and the seam. For some reason this works a zillion times better than pins. It also has the virtue of ensuring the zip matches up evenly on both sides of the opening – extra-useful when the zip crosses a horizontal seam like a yoke or waist seam. AND it makes sure I don’t get muddled up halfway through and set one side in back to front or round about (ask me how I know :-D)
I think this could do with a photo to demonstrate, but I don’t have one yet.
5 Sew the zip in using the invisible zipper foot. I find pinning it in place first made it harder, as the pins just warped the way the fabric was sitting. I also find making the presser-foot as heavy as I can (I have a little tension dial for it) stops foot sliding around on the slippery zipper-tape fabric, thus making everything neater.
6 Sew the seam beneath the invisible zipper up using the standard zipper foot. It is a bit of a pain to change feet so often, but it is soooo worth it. The standard zipper foot allows the invisible zip to sit with the closed teeth vertical, allowing the stitching to get in close to the end of the invisible zip, while keeping the stitching lined up with the zippers stitches on both sides. If I use my standard everyday foot, the zipper teeth invariably fall over to one side or another, making it impossible to get the stitching to line up with both sides. Even stopping a bit before I get to the teeth isn’t satisfactory with the everyday foot, as it still ends up pushing the two seam allowances below the zip out of alignment. The standard zipper foot eliminates this problem and also allows me to so quite close to the zipper, rather than leaving a little gap I need to sew by hand.
7 Sew the zipper tape to the seam allowance on both sides, below the end of the zip, so that when you want to put the garment on, you don’t have to wrestle to get the zip in the right place to do it up. This is not only good for my temper, I find, but is good for the longevity of that area of the garment, which can otherwise get a bit worn from above-described wrestling. (RTW garments don’t always have this done either. I have been known to do this step on rtw garments too.)
And that, my friends, is the collected wisdom of my invisible zip setting-in to date.