Mini Tutorial: How To Sew A Placket Front-Opening Zipper Application
1. Align the garment edges housing the zipper with face sides touching and edges aligning. Insert pins horizontally to secure the edges together. In this case, the same conventional steps used when sewing a regular seam are followed.
2. Switch your machine setting to the longest stitch length (this is called machine basting) and stitch the seam edges together at the designated seam allowance. In this case the seam allowance is 1". Once fully basted, clean finish each seam allowance edge individually using the finish of your choice. An overedge stitch like serging or zigzag is the fastest, most efficient technique.
3. Using a seam ripper, clip every 5-6 stitches along the entire seam length as shown above.
4. Gently open the seam allowance layers being careful not to accidentally pull the seam apart and iron the edges flat form the seam's wrong side as pictured above.
5. Place the closed separating zipper face down on the seam allowance layers such that the zipper teeth align with the seamline. Pin one of the zipper tapes to its corresponding seam allowance layer underneath, inserting the pins perpendicular to the edges a shown. It helps to move all garment layers out of the way during this process.
6. Using a zipper presser foot, stitch down the center of the zipper tape attaching it to the seam allowance layer underneath. Remove each pin as you approach it and try to keep the zipper perfectly aligned during this process.
7. Place the zipper flat on the table with its right side facing up and all garment layers directed away form it as pictured above. This should create a seam allowance fold on top of the stitched zipper tape. Insert pins perpendicularly through the folded seam allowance and zipper tape layer to keep the folded edges secured.
8. Using a zipper foot again, topstitch the folded seam allowance and zipper tape underneath, at about 1/8" away form the fold line as shown above.
9. Flip the zipper application on its right side and hand baste the zipper placket guide at the desired distance from the seam. The hand basting should be applied through the seam allowance and zipper tape underneath. It not only keeps all the layers flat and perfectly aligned, it also provides a topstitching guide in the machine stitching process.
10. Once the placket is topstitched and temporary hand basting is removed, you can easily separate basted zipper opening by pulling the seam edges apart. Doing so will release the clipped stitching and allow for easy separating- all you have to do is remove any loose threads caught within the folded edges.
The end result should be a perfectly aligned separating zipper that is fully enclosed by the topstitched placket without hindering its functionality and/or alignment.