Date: Thu, 7 Sep 1995 16:28:50 -0500
From: BJLK@aol.com
To: Multiple recipients of list <knit@geom.umn.edu>
Subject: Knit: Zippers (mostly tech)

I've been lurking on the knitlist for several months now, and have finally
found an excuse to comment on a construction issue.

It has been a while since I last inserted a zipper, but time-consuming trial
and error exposed me to quite a few pitfalls.  Inserting an inflexible thing
like a zipper into a very flexible material like a knitted fabric requires a
little more work than might be readily apparent.  Since I usually construct
garments without seams, adding a zipper before joining the pieces is not one
of my options.

First of all, the zipper needs to be planned as the opening is being made,
because adding a zipper as an afterthought can be a problem (as I have found
out the hard way).  If a cardigan pattern is being used, and the button band
is not more than one inch wide, this is the easiest way to go--work the
pattern as written eliminating the button holes.  If a pullover pattern is
being converted to a zippered front opening, it is necessary to plan a
non-curling zipper selvage edge for the left and right inside edges.  Three
or four extra stitches worked in garter or seed stitch usually works.
 Picking up stitches along the finished edge and working them later also
works, but not quite as smoothly.  The important thing to remember is to plan
ahead for the zipper placket.  Unless it is totally impossible or
impractical, I would suggest that the garment be tried on for fit and
appearance before proceeding with the zipper attachment.

When it is time to actually insert the zipper, I baste the front edges
together, making sure that they match row for row.  Then, the garment gets
turned to the wrong side, and the closed zipper is pinned into position.
 This is the time to check that the zipper is exactly the right length and
width (and is the separating kind for a cardigan--don't laugh, but I actually
did forget about this in my haste and attention to other details), and that
the zipper's color looks okay with the knitted fabric (because there may be a
subtle color problem which isn't be obvious until this moment, but could
really look awful, especially since it runs right down the very front and
will show whenever the zipper is open--another disaster I have lived
through).

The next step is to baste the zipper into position with a contrasting sewing
thread and running stitches about one-quarter inch apart--exactly on the line
that separates the plackets from the body (and about one-eight inch from the
zipper edge on the inside).  Turn the garment back to the right side and
check that the zipper hangs properly, does not pucker anywhere, and is
exactly where it should be.  If something doesn't look quite right, take out
the basting thread and try again (another hard-won lesson).  This is the last
time that adjustments can easily be made.

The tricky part of this business is to have the sewn-in seams on the "public"
and the "private" sides where they should be.  (I do a lot of turning back
and forth to check as I am basting.)  When this much has been accomplished,
the only thing left to do is actually sew in the zipper.  I prefer to do this
by hand with tiny back-stitches that go completely through both the zipper
and the knitted fabric, using the basting thread as a guide, because I can
make adjustments for the flexibility of both fabrics as I go.  (Just a picky
detail, but I do the "in" and the "back up" in two separate motions so that
the needle is always perpendicular to the fabrics).  The basting thread can,
however, be used as a guide for machine sewing, using a tension that is
neither too loose nor too tight (which I have never been able to accomplish
to my satisfaction.)  The tabs at the end of the zipper pieces then need to
be trimmed if necessary, turned under and secured along the top and bottom
edges.  When the zipper has been sewn in, check one last time from the right
side for general appearance before removing the basting thread.  At this
point, I sometimes also overcast or blind-stitch the edges of the zipper to
the insides of the fronts for a neater finish.  With all of this great care,
the zipper can be nearly invisible.

After going through all of this, it should be possible to open the zipper,
try on the garment, and have it fit well without unpleasant surprises.

Just as an afterthought, I have also put zippers into a "Henley-type" opening
at the neck edge using this technique.  The only difference is in planning
for the placket construction--the top placket may need to be wide enough to
cover the entire width of the zipper (rather than running up the middle), and
the zipper placement may need to be adjusted.  There are many ways to do
this, and referring to a specific pattern for guidance would most likely be
the best way to go.

[...]

B. J. Licko-Keel