How to Sew a Zipper Fly

Video Transcript

Would you believe me if I said that sewing a zipper fly is actually kind of fun? There are so many different ways to sew a zipper fly and some of them aren't really intuitive but I'm going to show you the tried and true method that we use here at Seamwork. My name is Haley and I'm the pattern designer here at Seamwork. I'm going to show you our favorite way to sew a zipper fly using the Ani trouser pattern as an example. Why do we like this zipper fly method so much? The reason is because it takes out all of the guesswork. We've designed our pattern pieces to be clearly labeled so you know exactly where to place your zipper teeth and exactly how to sew it all together. Let's get started.

First let's take a look at all of the pattern pieces you will use to assemble your fly. You have your front pants piece stay stitched at a quarter of an inch to prevent any kind of stretching. Then there's the actual fly piece itself. You'll cut one of these out of your main fabric and one out of interfacing. Then there's a fly guard. You'll cut one of these out of your main fabric. Finally you have your zipper. This pattern calls for a five inch or a seven inch coil zipper depending on the size of the pattern that you're making. Let's go ahead and assemble that fly.  

Start by interfacing your fly piece, then finish the curved edge of the fly, don't cut off any seam allowances when you're doing this. With right sides together and circles aligned, match the  fly to the left front piece. Pin and stitch from the waistline to the circle at 5/8 of an inch. Clip to the circle, but don't clip past the stitching. Trim and grade the seam allowance above the circle, 
don't trim any of the fabric below the circle. Fold the fly to the inside of the left front piece and press.

Clip 1/8 of an inch away from the circle on the rise of the right front piece. Finish the rise below the waistline to the circle, don't cut off any seam allowance. With right sides together notches and clippings aligned match the front pieces together at the rise. Pin and stitch from the circle to the inseam at 5/8 of an inch. Using a serger, finish the seam allowances together trimming off about a quarter of an inch. Start by serging at the inseam and then stopping at the circle. Fold the seam allowance of the right front piece out of the way in order to finish at the clipping. Press the seam allowance to the wearer's right side. Edgestitch along the left front rise to the circle.

Next assemble and attach your fly guard. With wrong sides together, fold the fly guard in half then press. Finish the raw edges of the side and bottom of the fly guard, don't trim off any seam allowance. 

Next it's time to sew the zipper fly. Lay the fly guard with the longer serged edge on the left and the folded edge on the right. Align the zipper tape right side up with the serged edge of the fly guard. The topmost zipper tooth will be a half inch down from the raw top edge of the fly guard. Using a zipper foot, baste the edge of the zipper tape a quarter of an inch away from the finished edge of the fly guard. Fold the unsewn edge of the rise on the right front to the wrong side at 3/8 inch. Press. Align the zipper in the fly guard unit to the right front of the waistline. Leave a sixteenth of an inch of the zipper tape showing between the teeth and the folded edge of the right front. Pin. Use a zipper foot to edgestitch close to the folded edge down the entire length of the 
zipper stopping at the circle.

Make sure that the zipper can open and close freely.  Unzip the zipper. Pin the fly guard away from the zipper. Fold the left front back behind the right front and away from the fly so it doesn't get sewn with the rest of the zipper. Pin the unsewn half of the zipper to the fly aligning the coil with the drawn guidelines and the topmost zipper tooth, which is a half inch down from the raw edge. Using a zipper foot sew the zipper to the fly a quarter of an inch away from the zipper coil. Double check that the zipper can open and close 
freely.

Next you can topstitch. Use a topstitching thread if you like if that makes sense for your pattern. A classic yellow or orange top stitching thread looks great if you're sewing a pair of jeans for example. Unfold the left front and lay it back into position and flat under the fly. Make sure the zipper is zipped up. On the inside of the pants baste the fly to the left front a quarter of an inch inside of the finished edge of the fly. On the outside of the pants, topstitch an eighth of an inch outside the basting stitches, then remove the basting stitches.

Unpin and flip the fly guard into place so that the front unit lays flat over the zipper. Pin the fly guard over the zipper. On the outside of the pants, bar attack at the top of the curve and then again at the bottom of the curve. Bar tack at the circle underneath the edgestitching on the left front. Unpin the front unit so you can continue to make your pants.

You've just installed a zipper fly! To watch the entire sewalong for the Ani trousers, head over to see the full class in the Seamwork classroom. Happy sewing!