We are back with another guide! This is how to insert a zipper around a circle. Really useful technique if you are sewing zippers for round purses or bags.
A curving zipper like this is most likely to be found on small pouches and purses, although you could also use one to open the end of a duffle or other round-ish tote.
From your project fabric, cut a 7" - 8" strip the width of the zipper. This will be the tab that holds together the ends of the zipper. You can choose a fabric to blend or contrast with the zipper. We chose a contrasting color.
- To determine the length of the tab, first measure the diameter of the circle onto which the zipper will be attached. For our sample, the circle diameter was 7".
- From the diameter, subtract ½", which is the amount of the circle's diameter that will be taken up with the seam allowance when stitching the zipper in place. For our sample, we are now at 6½".
- To get the circumference, multiply the diameter by pi: 6½" x 3.14 = 20.41". Round up to 21".
- Subtract the length of the zipper. For our sample, we wanted the full circle to open, so our zipper is the closest option to the full circumference or 20". 21" - 20" = 1".
- The finished tab length should be 1". To this finished length add ½" at each end to account for both seam allowances: 1" + ½" + ½" = 2".
After all this fun math, you now know you need a tab that is 2" x the width of the zipper.
With a fabric pen or pencil, mark horizontal stitching lines at each end of the tab. Remember, these are at ½" from each end.
Place the tab right sides together with the end of the zipper. The marked stitching line on the tab should be just above the bottom zipper stops. Stitch the tab in place.
NOTE: We are using a contrasting color of thread so it is easy to see our seams. You should use thread to best match your zipper.
Press the tab away from the zipper, as if extending the length of the zipper. This also reveals the remaining raw end of the tab.
Open up the zipper slightly and tape the top ends together to temporarily hold them in place.
Fold the zipper into a smooth loop; in other words, make sure there are no twists or turns in your loop.
Place the top end of the zipper right sides together with the tab. The second marked stitching line on the remaining raw end of the tab should sit just below the top zipper stops. Stitch the tab in place. Tear away the tape.
You now have a full circle zipper joined at the ends with your tab.
To allow the zipper tape to curve, snip along both sides of the zipper tape at a depth of about ¼". The cuts should be approximately ⅜" apart.
Open up the zipper all the way. Pin the zipper in place on your fabric circle. The sides of the snipped zipper tape should be flush with the raw edges of the fabric circle.
Attach a Zipper foot. Stitch this first side of the zipper in place all around. Again, we are using contrasting thread to emphasize our stitching. Stitch in a full circle.
Close the zipper to check your work. The zipper should sit smoothly and evenly all around.
If your project calls for it, this would also be the point to add topstitching around the first half.
Open up the zipper all the way again and attach the second half of your project to the remaining clipped edge of the zipper tape.
You've come full circle!
If your opening is not a full circle, you would not need a tab. The ends are simply captured within the seam as they would be with a straight edge opening. The key is in the clipping. Just as clipping fabric adds ease and allows the fabric to stretch and mold into a curve, clipping into the zipper tape will help the zipper sit smoothly along a curve.
credits to: sew4home.com