In this article, you will learn how to insert an exposed slot zipper. An exposed slot zipper is a visible zipper topstitched in a seam. It's sometimes called an exposed enclosed zipper or a closed-end exposed zipper.

Another way I customized my Stitch Sisters dungarees, along with sewing D-ring straps, was by inserting an exposed slot zipper.

(I love a dramatic fashion hardware moment!)

An exposed slot zipper marries the “theory” of a slot seam with the looks of an exposed zipper, which I’ve mostly seen sewn entirely on the exterior of garments.

In my internet research, I saw this zipper, or zippers spiritually close to it, called things such as “exposed enclosed zipper” or “closed-end exposed zipper.”

I think “exposed slot zipper” is as accurate as those titles, so that’s what I’m naming it!

Keep reading for photographed and nearly over-explanatory instructions for how to sew an exposed slot zipper — a visible zipper topstitched in a seam.

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A full-length photo of my Stitch Sisters dungaree bibs. They feature an exposed slot zipper.

What You Need to Sew an Exposed Slot Zipper

These are the sewing supplies you should have on hand to insert this type of zipper:

Directions: How to Sew an Exposed Slot Zipper

Materials for a sample exposed slot zipper.
This is a spare zipper I had in my stash. At one time I made a zipper stop on the teeth with a dense satin stitch.

1.) First, determine how much zipper tape you want exposed. Measure the zipper’s rectangle window (length and width).

Measure the zipper to determine ideal window length.
My rectangle needs to be 5.5-by-0.75 inches.

2.) Draw the rectangle window on tagboard.

3.) Draw a line in the middle of the window the long way (centered on the short edge).

4.) At one short end, draw a 45-degree line out of each corner to the opposite long edge. The two 45-degree lines will intersect at the center line. This little triangle will be folded toward the wrong side of your garment.

Draw the exposed slot zipper window template.

5.) Cut out the window using a craft knife, cutting around the triangle. You created TWO zipper window templates — a negative shape and a positive shape.

Cut out the zipper template.
Place the window template over the zipper to check if it's the correct length.

6.) Add interfacing to seam allowance, especially if the zipper is heavy duty.

6.) Baste the seam where the zipper will go.

7.) Finger press the seam. The fabric needs to “remember” the seam allowance.

8.) Place the template on the seam where the zipper will go. Make sure it’s centered and starts in the correct (final) location. (Remember that the RAW EDGE *probably* isn’t the final location; the zipper will start at a FINISHED (probably folded and stitched) edge.) You can use the negative or positive shape on top of the seam.

Place the zipper window template on the seam and trace around it.
The green dashes are where the fabric will be folded over and stitched down. I made the dashes with a permanent Sharpie marker so they’d be easy for you to see. (A Sharpie isn’t an appropriate fabric marking tool (in most cases).)

9.) Using your favorite marking tool, trace around the positive shape or inside the negative shape.

10.) On the right side, stitch over the traced rectangle window, taking care to NOT SEW through the seam allowance on the wrong side. (Use your fingers when stitching to ensure you’re not catching the seam allowance as you sew.) Use a thread color that’s close to the fabric. Don’t sew the 45-degree sides of the triangle; do sew the bottom short edge of the triangle. The stitching marks where edges of the rectangle window will be pressed to the wrong side.

The stitched rectangle window where the zipper will be inserted.
I stitched the window in a contrasting-color thread so it would be easy for you to see. When you stitch your own window, match it to the fabric so it becomes invisible.
The seam allowances are not sewn down.

11.) Take a pin and stick it through the point of the triangle, right side to wrong side. We’re marking the point so its location is visible on the wrong side.

Mark the point of the triangle.

12.) Fold the garment on the seam, right sides together. The wrong side should be up, with the bulk of the garment on the left and the seam and seam allowance on the right.

13.) Locate the triangle-point-marker pin. Mark the pin’s location on the wrong side with another pin, or make a line or dot with a marking tool. (In the photo below, it’s circled in white and the green marker is pointing to it.)

14.) On the wrong side, starting from the triangle-point mark, sew over the basted seam with a shorter stitch. This will make the seam below the zipper permanent.

Make the part of the seam below the zipper permanent.

15.) Using a seam ripper, remove the basting stitches that fall in the rectangle window. Only unpick above the triangle point (circled in white).

Remove basting stitches above the triangle point.

16.) Using a fabric shears, snip the traced, 45-degree sides of the triangle to — but not through — the bottom corners of the stitched window rectangle. (You will cut into the seam allowance.)

Clip to but not through the corners of the stitched zipper window.

17.) Fold the triangle to the wrong side along the stitched short side of the rectangle window and finger press. Turn the fabric to the wrong side. Snip through the seam allowance to make it lie flat (see photo below).

18.) On the wrong side, begin finger pressing the long sides of the rectangle window to the wrong side along the stitching, turning the stitches ever so slightly to the inside. Take care to keep edges and corners as sharp as possible. You’re helping the window “remember” its shape before pressing it with an iron. Speaking of…

Finger press the window open.

19.) Press the window using an iron and press cloth. Optional: Apply a hardwood clapper to the window after each press to lock in the folds as the fabric cools.

20.) Lay the zipper on your work surface, right side up. Lay the fabric rectangle window atop the zipper, right side up (wrong side touching the right side of the zipper). Adjust so the zipper is centered to your liking.

Center the zipper, pin it place, and topstitch it down.

21.) Pin the zipper in place, pinning through the window (two fabric layers — right side of fabric and seam allowance) and zipper tape.

22.) Using a zipper foot, stitch the window to the zipper tape. Start the line of stitching 1-2 stitches below the top of the zipper. The top of the zipper TAPE needs mobility in a few steps, so the tape can’t be stitched in place.

23.) When you stitch the short edge of the window near the folded-over triangle, you might want to lengthen your stitch and use the handwheel to move the needle. Consider using a larger-sized needle, too. There are many layers to stitch through, including the thick zipper tape; take it easy.

P.S. Don’t sew over zipper teeth. You could break a needle. Instead get as close as possible to the teeth and try to match the line from the other side. A hump jumper can be useful as you sew toward the zipper teeth.

P.P.S. If you’re ambitious, you can remove zipper teeth with pliers (or, if they’re plastic teeth, cut them away with scissors). Then, instead of sewing other zipper teeth, you’d sew over zipper tape (which is a lot kinder to needles).

24.) Give the window a final press. Make sure the portion of the window ABOVE the zipper — the part without the teeth — has crisp folds at the edges.

25.) Gently bend the top of the zipper tape that’s unstitched (above the zipper pull and teeth) AWAY from the crisp window folds (mentioned in Step 24). This part of the tape will be captured in the upper finished edge. Baste the tape ends in place.

The "raw edge" of the zipper tape is sewn into the top finished edge of the fabric.

26.) Finish the top edge of the garment, sewing the “unfinished” upper part of the zipper tape INTO this hem. Take care that both sides of the finished edge are even from left to right across the zipper.

27.) Finally, from the wrong side, press open the seam allowance BELOW the zipper.

And, you’ve done it! Check out your eye-catching — and functional — exposed slot zipper

Finished exposed slot zipper from the front.
Finished exposed zipper from the back.

This technique could be a fun way to add color, shine, and texture to a garment. Please LMK if you try it. My handle on IG is @sie.macht.sewing. ← Follow meeee! Please!

Over to you: What’s your favorite zipper to sew? I kinda dig on lapped zippers. They have a vintage energy, IMO.