You will need:
- a zipper opening (sewing project)
- A conventional zipper, the length that is required for your project
- Needle and Thread
- an adjustable sewing machine foot
Step 1: Prep your zipper by unzipping it and giving it a good press with a hot iron. Under no circumstances should you place the hot iron directly on the coils or teeth of the zipper (unless you have a handy dandy metal zipper)! They will melt and even though for a time, the zipper will still zip up and down, eventually the zipper will blow out.
Optional, though highly encouraged: Prep your zipper opening by applying 1 1/4" strips of fusible tricot, silk organza or stay tape (the knit variety is my favorite for zippers) to the wrong side of the zipper opening - or the side that won't be showing on the outside of the garment. Additionally I would like to add that I am a firm believer in stabilizing zipper openings as I feel they just last longer and look cleaner and more professional, but ultimately the choice is up to you. As you'll notice here, I conveniently forgot to add this step......my public flogging will happen later, don't worry.
Step 2: Pin and baste your zipper opening closed. You can baste the zipper opening by hand or by machine - just use a really big stitch if by machine. Be aware that this zipper closure requires at least a 5/8" seam allowance or larger. Also, if you're putting this zipper insertion style into say, a skirt, baste the zipper opening to the bottom of the zipper and from there stitch (and backstitch in place at the bottom of the zipper opening) the rest of the seam that the zipper is in using a regular stitch length.
Press the zipper opening (and seam) open.
Step 3: If needed, whipstitch the top of the zipper tape together. This is a good idea if the zipper is in the side seam of a dress. For those applications where the zipper needs to be open at the top, skip this step.
Step 4: On the wrong side of the fabric or garment, position the zipper to one side of the seam allowance. When positioning, the zipper teeth should be directly over the middle of the seam allowance or the seam line. Pin in place keeping the seam allowance the zipper free from the garment. Baste the zipper to the seam allowance (still keeping free from the garment) along the edge of the zipper tape furthest away from the coil or teeth.
Helpful tip: When deciding which seam allowance this the zipper should be basted to at this point, be aware that this part is the part that is under the lap on the right side of the garment. For example, if you baste the zipper to the left seam allowance the lap on the right side of the garment will be right over left and vice versa.
Step 5: This is the tricky part, because its a little awkward to explain. From here, flip the zipper over to expose the right side of the zipper. Create a little fold along the teeth/coil with the same seam allowance that you just basted the zipper to. Keep this seam allowance and the zipper free from the garment. Pin in place if needed and using your adjustable zipper foot, stitch close to the zipper teeth/coil along the fold.
Step 6: Turn the garment or sewing project to the right side. Now pin the leftover seam allowance and zipper tape to one side of the zipper opening - the side that hasn't been stitched in place and all that jazz. Pickstitch around the top (for side application on a dress), down the side and at the bottom of zipper. You can also do this step by machine if you desire. To prickstitch, use a backstitch, stitching a small stitch on the right side of the garment and using a longer length on the backside of the garment. The result will look like little pricks on the right side of the garment. Here's a link to a great video on the subject.
Step 7: Last thing to do is unpick the zipper opening (carefully now) and Voila! a beautifully lapped zipper is now most discreetly adorning your handmade garment.