Zippy Zippers

History

The prototype for today's zipper was actually a series of hooks and eyes that closed mechanically (1).  It was invented in 1891 by an engineer named Witcomb L. Judson.  First used as a closure for mailbags, tobacco pouches, and boots, Judson's zipper was eventually adapted for use in clothing and marketed as the "C-Curity Plaket Fastener." The early zipper was not an immediate success because it was rather crude and tended to come open.

The zipper has come a long way since then.  At first, zipper teeth were stamped from metal and clamped to the zipper tape.  The metal teeth originally made this process very rough, and tended to jam the zipper or separate from the tape.

Major progress was made when the Crown Zipper Co., owned by Coats and Clark Inc., designed a die-cast zipper in the 1930's.  By 1950, die-cast zippers were produced in Canada by J.&P. Coats.  The metal teeth are molded directly onto the zipper tape, making  it almost impossible for them to jam or come loose.  The edges of the zipper teeth are rounded so that they interlock smoothly and easily.  

At the same time, the possibility of a coil zipper was being researched in Europe.  The first coil zipper was made of two interlocking brass coils.  However, these coils could be permanently bent out of shape, making it impossible to operate the zipper.  It wasn't until after the discovery of stronger, more flexible synthetics that a viable coil zipper could be designed.  Coil zippers became an important part of the zipper market in the early 1960s. 

Anatomy of A Zipper

A zipper is a closure consisting of interlocking coils or teeth, attached to tapes, and operated by a slider. 

Basically, the coils or teeth "hook" together within the slider (2).  The inside of the slider is curved, and as the slider is pulled up, it spreads the coils or teeth apart.  Each coil or tooth fits snugly between two or more from the opposite side.  They interlock, and the tape straightens.  (This procedure is reversed to open the tape.)

There are two types of conventional zipper construction: coil and metal.

Polyester Coil Zippers are lightweight, yet strong. Polyester coil is stronger than nylon.  These zippers are flexible with low shrinkage and are easy care as they are heat-resistant and rustproof.  The covered back of coil zippers protect undergarments.  The coil is self-healing and the slider is self-locking.

Zipper Selection

To select the proper zipper length, check the pattern envelope and consider individual body proportion.  Remember that a long zipper opening reduces the strain on a zipper when getting in and out of a garment.  

To choose the appropriate type of zipper, consider the garment design, fabric weight and colour.

There are 6 types of zippers to choose from, see below:

1. Polyester all-purpose zippers are suitable for fabrics of all weights in skirts, pants, dresses and home decorating items.
2. Metal all-purpose zippers are strong, durable zippers for sportswear as well as pants, skirts, dresses and home decorating items.
3. Brass jean zippers are stamped metal zippers with a closed bottom, designed for jeans, work and casual wear in medium to heavyweight fabrics.
4. Metal separating zippers, available in medium and heavy weights, are used in jackets, sportswear and home decorating.  Reversible separating zippers have pull tabs on the front and back of the zipper.
5. Plastic molded separating zippers are lightweight yet strong and durable, designed with extra fullness to give a smooth, straight finish to the application.  Their decorative appearance makes them a natural for skiwear and outdoor wear.
6. Parka zippers are plastic molded separating zippers with two sliders, so they can be opened from the top and bottom.

Applications for 
Conventional Zippers

Separating zippers in jackets and vests can be inserted with zipper teeth covered or exposed.  A decorative sport zipper with plastic teeth is lightweight yet sturdy, for active sportswear.

Lapped application, also called an Invisible zipper, totally conceals the zipper, making it a good choice for zippers which do not perfectly match the fabric colour.  It is most often used in side seam closings of dresses, skirts, and pants.

Centered application is most frequently used for center front and center back closings. Attach facings before inserting zipper.  Waistbands should be applied after zipper is inserted.

Zipper Prep 101

Wherever possible, apply zipper in a flat section of the garment before any seams are sewn.  If fit is a problem or if the garment includes special design features, apply after construction.

Unless zipper is 10% polyester, pre-shrink zipper.

Press folds (if any) out of zipper tape by pressing zipper from wrong side.

Length of Zipper & Zipper Opening

To determine the length of a conventional zipper, measure from lower edge of bottom stop to top of slider with zipper completely closed.

In a finished zipper application, the zipper opening should always extend a little beyond the top of slider.  To determine zipper opening, measure zipper, then: 

Zipper Conversion Chart

A Word About Seam Allowances

Reinforce and widen with seam binding if fabric ravels; if seam is less than 1.5cm (5/8"); or if zipper has a large pull tab.

Stabilize zipper opening with staystitching, 6mm (1/4") from the cut edge, if fabric is stretchy, loosely woven, or cut on the bias.

Reducing Bulk

Interfacing: At zipper opening, trim interfacing back 2cm (3/4").

Cross Seams: A seam crossed by a zipper should be graded to reduce bulk. Start 2.5cm (1") from edge and trim seam allowance to 1cm (3/8").  Clip and press trimmed section open as shown (3).

Basting Seam Closed 

Close seam before installing conventional zipper.  With regular stitch length, stitch from hem to bottom of zipper opening.  Back-tack.  Adjust stitch length to longest stitch and complete seam.  Clip basting at bottom of zipper opening (4). Press.

Topstitching

To ensure straight topstitching, use one of the following methods:

Shortening a Conventional 
(Coil or Metal) Zipper

For garments with a waistband, shorten zipper at the top.  Install zipper.  Open zipper and stitch across top of tape within the waistline seam allowance.  Cut off excess zipper tape at raw edge of waistline (7).

For other garments, shorten zipper at the bottom before installation.  Measure desired length.  Whipstitch tightly across coil or teen 8 to 10 times with double thread.  Cut zipper 1.3cm (1/2") below stitches (8).  Install zipper.

Another way to shorten a zipper is to measure desired length along the coil, beginning at the stop stop.  Mark with a pin (9).  Machine zigzag across the coil at pin to form a new bottom stop (10).  Cut off excess zipper and tape.  Insert zipper as usual, stitching slowly across coil at bottom. (11)

Zipper Care

Press zipper area using a press cloth to prevent a shine on the outside of the garment.  Press curved seams over a pressing ham.

Keep zipper closed during washing and dry cleaning and while garment is not being worn.

Use beeswax or zipper lubricant if zipper is stiff or difficult to operate after dry cleaning.

Zipper Foot

A zipper is installed with the aide of a zipper foot so that stitching can be done close to the coil or teeth.  For a conventional zipper, use a regular zipper foot that accompanies the sewing machine.  An adjustable zipper foot permits stitching on either side of the zipper.  This allows directional stitching and better placement of seams.  No part of the zipper foot should ride on the zipper teeth.

Finishing Touches

Hand Applications

Completing the final stitching of the zipper application by hand gives a garment a custom look.  Why not take the opportunity to decorate your zipper with embroidery, beading, or sequins.

Visible stitching is done with a hand backstitch or pickstitch, approximately 6mm (1/4") apart as shown (13).  Use a single length of buttonhole twist sewing thread.

Neck Fastenings

For fabrics that do not snag, use hooks and eyes.  For other fabrics, use extended or hanging snaps.

Extended snap (14): Fasten ball sections of snap to inside of neck edges.  On opposite side, attach socket section, sewing through one hole and extending it beyond edge.

Hanging snap (15): Similar to extended snap, except that socket section is attached to facing with a French tack.

Waistline Stay

Alleviates strain on zipper, making it easier to open and close.  We recommend it for garments with waistline gathering, stretchy fabrics,  or a skirt heavier than the bodice.

PROCEDURE (16):

1. Cut 2.5cm (1") wide grosgrain ribbon the waist measurement plus 2.5cm (1").  Turn ends under 6mm (1/4") twice and secure.  Sew on hook and eyes.

2. Pin ribbon to waist seam allowances so that hooks and eyes face zipper.  Ease seam allowances to ribbon if necessary.  To eliminate bulk, position fastenings to left or right of zipper.

3. Stitch to seam allowances through center of ribbon, leaving 3.8cm (1 1/2") free on either side of zipper.  For a princess style dress, tack ribbon to darts and seams.

Lined Garments

PROCEDURE (17):

1. Sew lining sections together leaving seam open in zipper area.  Fold free edges of lining under and pin 6mm (1/4") from center of zipper.

2. Slipstitch lining to tape.

3. Hand stitch a second row of stitches 6mm (1/4") from folded edge.

Construction Measurements

Here are some of the metric measurements that are used most often: