Tuesday, May 11, 2010

Sewing An Invisible Zipper Into An Opening With Intersecting Seams

You'll come to a crossroads whenever you're installing a zipper into a dress that has a bodice joined to a skirt, or even just a skirt that has a wide, yoke waistband. You've got the vertical zipper seam to deal with, and then you've got two, horizontal seams that match, right? Those are called intersecting seams. I think of it as the "Four Corners" dilemma in sewing. (You know, Utah, Colorado, New Mexico, Arizona?) Sew that zipper in even a little bit wrong, and the seams won't intersect nicely, and you'll have a garment that whimpers, "Someone made this." Eww.

I was sewing this dress from Go Patterns on my annual trip to the San Francisco Sewing Experience with Sandra Betzina in 2008 when she taught me the trick to getting great results when you're at this Four Corners crossroads. To do it, you'll need a couple of inexpensive and readily available tools: Wonder Tape, wax chalk, and a quality invisible zipper foot. And there's no pinning and basting involved!

I follow Sandra's directions in her book, Power Sewing Step by Step, for invisible zipper sewing in general. The first thing is, open the zipper, place it face down on your ironing surface, and with the tip of your iron, press those coils open and flat. (Take care with the heat, now, because you'll never melt the coils of your zipper at a time when it's convenient for you to head back to the fabric store for another one.) I like to use my point presser/clapper to hold the whole thing flat while it's cooling off, but you can use anything that's long and flat and slightly heavy to do the same thing, such as a clean and splinter-free piece of 2 x 4.

Have you ever reinforced the seam allowances of your zipper opening with narrow strips of fusible interfacing? I wish someone had told me this years ago. It really makes those seam allowances behave.

Next, finger press the seam allowance (very likely you're using 5/8") on one side of the zipper opening. That just means to use your finger or fingernail to crease a fold in the fabric — not your iron. The reason? This fold is only temporary. We don't want it pressed in with heat.

Then, get your wonderful Wonder Tape and reel off a length of it that's as long as your zipper. (Wonder Tape's double-sided and sticky, but the adhesive will launder out.) Apply the Wonder Tape to your seam allowance.

Peel the release paper from the tape, leaving behind a nice little strip of sticky stuff. Next step is to place one side of the zipper on this line of sticky stuff, and it requires a moment of your total concentration. Ready?

Make sure the top stop of the zipper is indeed at the top of the zipper opening. (Zippers that are installed upside down aren't so handy.) Make absolutely sure your coils or "teeth"of the zipper match up evenly to your finger-pressed fold of your seam allowance. (If you get the coils a little too far away from the fold, or a little too far over the fold, your invisible zipper won't look so invisible.) Your zipper is, at this point, securely (and temporarily) attached to the seam allowance. No pins are necessary! Unfold your finger-pressed zipper seam allowance and lay it out flat. You will have just the one layer of your garment fabric on bottom, and the Wonder Taped-on zipper on top.

Now, go to your machine and stitch all the way down the length of the zipper tape. You will need to use the best quality invisible zipper foot you can find for this. A lot of newer machines come with them now, or they're easily ordered online. For successful invisible zipper sewing, you must stitch very close to the coils, and the invisible zipper foot is what allows you to do that. (Sew too close and you won't be able to even close the zipper —ask me how I know. Too far, and and you will have seam allowances that gap and expose your "invisible" zipper.)

Still with me? Remove your work from the machine. Close the zipper now, and lay your garment flat. Find the horizontal seam — in this case, I'll call it the Utah/Arizona border. Using your wax chalk, make a mark right on your zipper that lines up exactly with the line between Utah and Arizona. I like wax chalk because it doesn't brush away very easily, and no one will ever see this mark.

It's time for the other side of the zipper. Make a finger-pressed fold on the remaining zipper seam allowance, just like you did on the first seam allowance. Apply Wonder Tape to the seam allowance, yes, just like you did the first time. Peel off the release paper from the Wonder Tape and expose a line of sticky stuff. Now, open your zipper. Find your little mark you made on the zipper when you were at the Utah/Arizona border. Carefully line up this mark to the opposite horizontal seam — the Colorado/New Mexico border, if you will. Now you can finish sticking down the zipper to the seam allowance, taking care to match the coils perfectly on your finger-pressed fold, the way you did the first time. Unfold your finger-pressed seam allowance and lay the work flat.

Okay, this might the time you pin the zipper tape to the garment fabric. But you really only need to pin right at the horizontal seam, to ensure that your chalk mark stays precisely where you want it — on the Colorado/New Mexico border. Sandra recommends cross pinning, or putting two pins in an "X" formation for this.

Return to your machine and sew the remaining side of your zipper to the seam allowance. You're going to be so excited when you look at what you've done — Four Corners!

Finish closing the garment seam allowances as you usually do when you sew an invisible zipper.

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