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Zipper basics and sewing techniques

Interior, Shop Techniques | January 1, 2019 | By:

Photo 1: YKK’s Marine Mates® UV VISLON® zipper is designed
to resist damage from sunlight, as well as corrosion.

The zipper is familiar to everyone, yet the word itself came into existence less than 100 years ago. The fastener’s design was a lengthy process. An early version was invented by Elias Howe, the man who also invented the sewing machine. He patented an “automatic continuous clothing closure” in 1851, but it didn’t catch on.

The button’s dominance began to decline when Gideon Sundback, a Swedish inventor working for the Universal Fastener Company, improved on Howe’s design with his own “separable fastener” in 1914. But it wasn’t until 1923—when the president of B.F. Goodrich rubber company decided the device needed a modern name: “Something that will dramatize the way the thing zips”—that the name “zipper” was born!

Photo 2: The LENZIP No. 12 Marine Grade UV Zipper is larger than the industry standard and is available with 316 stainless steel sliders.
Decisions, decisions

Marine zippers are available with metal, plastic or stainless steel sliders. Both teeth and coil zippers are available from marine distributors in standard lengths from 24 inches to more than 96 inches. Sizes typically range from #5 through #12. Teeth and coil zipper tapes are also available by the yard and/or roll.

For projects with straight lengths or slight curves, the teeth zipper is your best option. For a project that includes a curved contour, the coil zipper is your best option. Black and white are standard color offerings, however some models are available in a wider range of colors.

Zipper manufacturers

YKK Group­—Tadao Yoshida opened his Japanese zipper firm in 1934. He reverse-engineered the original zipper and helped make YKK a universal brand.

Photo 3: Sunbrella® Performance Zippers feature tape made using 100 percent Sunbrella fibers.

Lenzip—Headquartered in Rolling Meadows, (Chicago) Illinois, Lenzip has been in business since 1946. Its product line consists of nearly 1,000 different zipper styles, manufactured from metal, molded plastic and coil zipper materials. Lenzip can custom make just about any zipper and offers a lifetime warranty on its zippers, which are also YKK compatible.

Ideal Fastener Corp.—The manufacturer entered a licensing partnership in 2017 with Glen Raven Custom Fabrics, the maker of Sunbrella® performance fabrics, to offer the first zippers with the zipper tape made from 100 percent Sunbrella fibers.

These marine zipper manufacturers have extremely helpful websites, as do many zipper suppliers. Take a moment to check these out to help you make the best zipper choices for your projects.

Terri Madden owns Sand Sea & Air Interiors Inc. in San Juan, Puerto Rico.

  1. Top tape extension
  2. Top stop—This prevents the slider from coming off the chain.
  3. Slider—A device that moves up and down the chain to open or close the zipper.
  4. Pull tab or puller—The part of the slider held to move the slider up or down.
  5. Tape width—This refers to the width of the fabric on both sides of the zipper chain.
  6. Chain or zipper teeth—A continuous piece that is formed when both halves of a zipper are meshed together. Chain width refers to the specific gauge of the chain. Common gauge sizes are #3, #5, #7, #8 and #10. The bigger the number, the wider the teeth/chain.
  7. Bottom stop—A device affixed to the bottom of the zipper to prevent further movement and the zipper from separating.
  8. Bottom tape extension—The fabric part of the zipper that extends beyond the teeth at the bottom of the chain.
  9. Single tape width—This refers to the width of the fabric on one side of the zipper chain.
  10. Insertion pin—A device used on a separating zipper that allows the joining of the two zipper halves.
  11. Retainer box or pin box—A device used on a separating zipper that correctly aligns the pin to begin the joining of the zipper halves.
  12. Reinforcement film—A strip of plastic fused to each half of the zipper tape to allow a manufacturer to electronically “weld” the zipper onto the garment or item that is being manufactured, without the need of sewing or stitching.

Sewing a smile zipper on the mesh bottom of a cushion makes it easier to insert a beefy piece of foam. A mesh base allows for airflow. Here’s how to prepare your cover to fit a large piece of foam into a cushion when a side-band zipper is not an option:

  1. Make a pattern of the cushion area.
  2. Evaluate the shape/space–sketch a smile access on the inside of the mesh, as large as possible for the zipper opening.
  3. Measure the length of a #5 tooth zipper for the size of the intended opening.
  4. Adjust the zipper along the contour.
  5. On the inside contour of the zipper, sew a running stitch to reduce the zipper area. Pull threads and knot to hold in place during sewing.
  6. On the outside contour of the zipper, mark indicators to slit with a hot knife; this will enlarge the outside zipper area.
  7. Using a zipper foot, sew as close as possible along the outside zipper tape edge. Secure the outside zipper edge to the mesh next to the sketch line on the mesh. As you sew, pull the outside edge of the zipper to fit the contour.
  8. Sew as close as possible along the inside zipper tape edge.
  9. Turn to the outside of the mesh panel (this will be the visible bottom side of the cushion).
  10. Carefully cut the mesh along the center of the zipper teeth. You should have about 1/3 inch on each edge along the zipper smile.
  11. Carefully press and fold the lip of the mesh toward the stitching. Pin/staple as needed to prepare the mesh.
  12. Slowly stitch along the tip of the folded edge, securing the mesh, inserting a slider(s) and allowing space for the zipper carrier(s) to travel the contour. *TIP: We generally use two sliders faced toward the inside foam area. This makes it easier to place the foam inside the cover.
  13. Fold and secure the mesh at the ends. Use vinyl reinforcement over the start and stop ends of the zipper.

This technique also works well on large interior fabric boat cushions when you don’t want zippers on the side bands. Vinyl (instead of mesh) works well, and you can just cut down the center of the vinyl to access the zipper.

Here’s an easy process that we use as an employee training technique.

  1. Take the measurement for your final band width: For example, 4”.
  2. Add seam allowance (our shop uses ½” standard): 4” + 1”.
  3. Add 1” zipper seam allowance: 4” + 1” +1” = 6”.
  4. Cut band in half: 6”/2 = 3”. (You now have two bands that are 3” wide.)
  5. (Photo 1) Stitch length of zipper on top of the outside edge (blue vinyl) with the zipper tape facing you. Continue sewing the length of the band.
  6. (Photo 2) Turn/fold each zipper edge (½” seam) to the back with the inside of the vinyl facing you as you topstitch along the zipper tape. Proceed to stitch close to the teeth, aligning the teeth and folded edge with the underneath vinyl. Sew both bands that are now 4”.
  7. (Photo 3) Insert carrier(s). Join centered 4” zipper band to 4” side band.
  8. Sew zipper band to upper and lower faces with ½” seams. Result is 3” finished side and zipper bands.

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