#bpsewvember Day 25 Oh No! reminded me that I had taken these zip images while I was recently making up sample garments.The invisible zip used to always seem like the biggest challenge of all the zips. But over the years I’ve decided that with all types of zip insertions having a decent amount of seam allowance is a key element in their success. My sewing machine is a Bernina and the zipper foot that came with it makes you move the needle position rather than the foot itself!! So you can imagine the amount of needles I’ve broken when switching back to the normal foot?! This system doesn’t allow you to sew too closely to the zipper teeth which is actually much better, particularly if there’s a facing/ lining which adds bulk to where the zip has to pass through and can be so close that the zip can get stuck or caught into the fabric. When the zip is in place it will need to be pressed. With invisible zips I don’t press onto the front or back of the zip or fabric, I press up and under, onto the seam and the stitch line and the fabric I may give it a pat with a cloth afterwards (usually only on bulkier fabrics like wool) but I’ve used this method for a long time now and it never leaves any unwanted wrinkles or zip teeth or seam impressions.
I always mark the length of the zip onto the unsewn seam and then shorten it by about 3cm, by that I mean move it up, this does shorten the zip length. I sew the seam first. I sew invisible zips in when they are open, the shortened zip length allows you space to grip the zip puller from the wrong side and then catch hold of the zip puller and manoeuvre it past the start of the seam and on to its final position. I match the top of the zip tape with the top of the garment piece. I never cut or trim away the corners, I use these seam allowance pieces to form rigid, squared corners. It is important to accurately measure the zip, I have seen many stretched zip seams in my time and the only thing to correct it is – unpicking!
An invisible zip with a seam running through it. Never leave it to chance that they will match, because, from experience, they never do. So give it a bit of preparation and mark exactly on the zip tape where the seam should sit, I centre the teeth of the zip with my set square and mark, check again, sew in the first side, check again, pin if required, then sew the second side. I always sew down one side and then back up the other side, this counters any accumulative stretching which can occur if you only sew in one direction.
Much better to take the time to mark it and spare yourself the disappointment of a mismatch. These fabrics were all a good weight for sewing in the zips. However the meanest fabric I’ve put an invisible zip in recently was for a sample dress, £40 per metre fabric and it showed every mark! Fabric at that price should be a joy to sew with!!