Of all the zippers that can be applied when you are sewing garments — invisible, lapped, exposed — the conventional zipper, aka the railroad zipper, is by far the most difficult of them all to insert. When it comes to inserting zippers, this particular zipper is far more difficult than the often feared invisible zipper. How is that possible?
The Trouble with Inserting Railroad Zippers
For this zipper to look good, and I mean really good, the exposed stitching that surrounds the zipper must be perfectly straight and evenly spaced. And the zipper teeth must be centered within the seam opening. No easy task, even for yours truly, who has been sewing, like forever. Making sure that happens requires a focused attention to preparing for that final step. Here, we will take a look at how to insert a railroad zipper.
Granted, applying this common type of zipper requires very few steps, which at first, sound rather easy to accomplish. But the devil is in the details when it comes to making sure this zipper looks professionally done. It’s all in the prep work that counts.
Follow these steps to simplify the process of inserting a railroad zipper:
It starts with baste stitching the zipper opening with the usual ⅝" seam allowance. Now, press the seam open. Working from the right side of the project, draw stitching guidelines to help frame the zipper. This is one of the most important prep steps, so do it carefully and as precisely as possible. I prefer to use a fine-tip fabric marking pen to draw the lines. Make sure your lines are exactly ¼" - ⅜" from each side of the center seam line.
Use a zipper that is 2" longer than needed. Don’t worry, you’ll see why in just a moment. Working from the project's wrong side, take that zipper and lay it over the center seam line with the zipper tab positioned above the top edge. And, I mean lay that zipper exactly over the center line. This is one of those really important details that will make a marked difference in the finished appearance of this zipper.
To hold the zipper securely in place, hand baste the zipper in place. Or, you can simply use scotch tape to secure it. This again is another important detail that will ensure the zipper teeth remain perfectly centered and securely in place.
Your prep work is now done. The zipper is securely centered over the center seam line. That annoying tab that always gets in the way distorting your stitching lines is no longer a problem. The center seam line stays intact. And you have a set of guidelines that will ensure the stitching that frames the zipper is straight and even on both sides of the center seam.
Remove the tape from the back of the zipper and undo the basting stitches that are holding the center seam together. Now open the zipper so the zipper tab is midway into the zipper opening. The excess zipper that hangs above the top edge can now be trimmed even with the top edge.
The method in which the top edge is finished, either with a waistband or facing, will contain the zipper tab and prevent it from running off the garment. For added insurance, you may hand sew several stitches around each side of the zipper teeth ¾" below the top edge, which in essence serve as bumpers or stops (done in contrast color in the photo for teaching purpose).
Voila! A zipper you can be proud of. Prep work is important in sewing. Of course, it adds extra time and labor to the process, but it can also turn a homemade project into a professional looking one.
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