How to Sew a Fly Front Zipper Like a Boss

During my time teaching women how to sew, I have learned that there are certain things that are universal fears among beginner sewists. One of them is their loved ones using their fabric scissors to cut paper and the other is closures. Yes, you know what I’m talking about – buttons, zippers, elastic – I can hear you screaming “just stop it right now, Jessica!”

But you know I can’t. I can’t let you stay scared of something that just ain’t that scary!

Can’t use this tutorial right now? Pin this image to bookmark this post for later!

Now the mother of all closure scariness is absolutely the fly front zipper. I’ve seen ladies resort to some pretty sketchy things to avoid these and it gives me all sorts of feelings. Confusion, sadness, fear. Somebody hold me.

So the times has come my friends. No longer will you wear stretchy pants in a non-stretchy pants situation! No longer will you shy away from gloriously structured woven pants that make your caboose look like it was chiseled with the precision of the Greeks! From now on you will henceforth and forever more, be a sewist without fear. So let’s freaking do this.

First thing’s first. If you aren’t familiar with zippers (the different types, sizes, etc.) then check out this Guide to Understanding Zipper Types, Weight Sizes, and Parts First.

Watch and Learn – Video Tutorial

Here is a video tutorial for those of you who just can’t even with written and picture tutorials <3

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Step by Step

Prefer to have the tutorial in your hands? Download the mini ebook!

1. Prep your fly extensions by finishing the curved edge with a serger, zig zag or overcast stitch.

2. Prep your fly guard by folding and pressing it in half with the wrong sides together and finishing the raw side and bottom edges.

3. Attach the fly extensions to the inside of the front legs with the right sides together, aligning the pieces at the top raw edges. Use a 1/4” seam allowance and a finishing stitch and continue to the bottom of the crotch to finish the inner edges.

4. Press the fly extensions out with the seam allowance facing them.

5. Understitch your seam allowances to the fly extensions.

6. Cut into your seam allowances right underneath your fly extensions. Do not cut past your seam allowance.

7. Lay your two front pieces on top of each other with the right sides together. Sew them together beginning at the base of the crotch and stopping at the bottom of the fly extension. Use a 5/8” seam allowance.

Then switch to a longer stitch length and baste stitch up to the top. Your basting stitches will be 3/8 of an inch away from your fly extension seam.

Flip your top fly extension back so that its right side is now facing up. Place your zipper face down so that the teeth are on top of the bottom fly extension.

8. Secure with invisible tape and stitch down the right edge of the zipper tape using a zipper foot.

Don’t have a zipper foot? Find one here:
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9. Fold the zipper and the right side fly extension underneath the pants.

10. Fold the inside of the fly guard in so that it’s  barely up against the zipper teeth.

11. Layer the fly guard underneath the zipper and bottom fly extension. Topstitch through all layers next to the zipper teeth.

12. Finger press the top fly extension back over the zipper.

13. Flip everything over.

14. Pin the fly guard back out of the way.

15. Stitch the left zipper tape to the remaining fly extension next to the teeth.

16. Lay everything flat with the wrong sides facing up.

17. Pin only the top of the fly guard out of the way.

18. Flip everything over and top stitch along the fly extension and over the base of the fly guard being careful not to sew over your zipper stop.

19. Pick the remaining basting stitches at the top of the fly.

Great job! Check out that beautiful fly.

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