Anyway, onto the invisible zip...
In case you don't know the difference between a regular zip and and invisible one, an invisible zip's teeth curl inwards so that when you zip the zip up you can't see them from the RS. When you have sewn an invisible zip into the garment properly, all you can see is the zip pull, whereas with a regular zip you would see topstitching and a sort of pleat under which you have the zip.
An Invisible zip is sewn in differently to a regular zip. You insert the zip before you sew the seam. Also, you can't sew all the way down it so you need a zip that is at least about 2" (5cm) longer than the opening. You can easily shorten the zip if you have to.
TIP: If you sew at an angle so that it looks like you're going to sew diagonally through the teeth, it will be easier to stitch in the groove of the zip. You still have to open the coil far though, so that the teeth are perpendicular to the tape. In this photo I haven't got them pushed back far enough, but if you get them right, the results are better. It will be easier to sew the zip in properly if you machine baste it in first. Yes, it takes more thread, but it is worth it.
You will have to stop stitching about 1/2" to 1" above the zip pull. When you sew an invisible zip you will see why. Backstitch and tie off. Repeat for the other side, keeping the notches on the seam allowances matched.
Note: It may be easier or better to sew below the bottom of the zip by hand with doubled thread if you can't get it just right. (It is very hard.) Then sew the rest of the seam by machine.
After that you sew the rest of the dress.
Next week, we'll sew the front of the dress to the back of it and insert or "set" the sleeves. Plus, assuming the Blogger thing works right, I'll post a little video on ease-stitching the easy way (if only I had know about this when I did my first course!). It is my first online video and I felt almost nervous, so there is no speaking in it : ).
Until next time, Happy Sewing!
The Sewing Corner, 41 Market Place, Hornsea, East Yorkshire, HU18 1AP
P.S. You can sew an invisible zip in like a regular zip if you like. They are actually easier than regular zips that way. I know because on my first dress, I sewed one in using a centred zip application. You can get quite a narrow finish that way. : )