Monday, October 22, 2012

Zippers in knitwear, the no-sewing way

This article about installing zippers was featured in the winter 2010 issue of Interweave Knits.  TECHknitting blog has had a few posts which refer to this technique, but the details have never been actually published to the internet. The copyright has now reverted to me, and TECHknitting blog is publishing all the details for the first time, complete with illustrations.  There is also an accompanying video in which Knits' editor, Eunny Jang, demo's the how-to.

* * *

Do you avoid making zippered knitwear because of the sewing involved? Here's a way to install zippers with no sewing at all. Instead, you literally KNIT the zipper in. To prep the zipper to perform this magic trick, we'll borrow a tool used in rug-making and machine knitting--the latch hook.

Latch hooks come in many sizes, but the one for us is a miniature version called a "knit-picker" or "snag-fixer." Available in fabric stores for a couple of bucks, these are meant for pulling snags to the inner surface of industrial knits such as polyester polo shirts. We, however, are going to use this mini-latch hook for our own hand-knitting purposes: to pull yarn loops through the fabric tape of the zipper--perfectly spaced loops which can then be picked up and knitted (or bound off). 

In essence, a latch hook is nothing more than a foolproof crochet hook--foolproof because the little latch can swing open to catch the yarn, then swung shut, trapping the yarn under the hook.  Once the yarn is safely caught under the hook and the gate latched shut, the loaded hook can be drawn through even the tightest hole without any danger of the yarn fraying or splitting, because the latch locks the yarn in.

Close-up of knit-picker, with latch open (L) and shut (R)

Specifically, in our use, the latch is going to be swung open, then the hook is going to be poked through the zipper tape at a pre-marked spot, shown by red dots on the illustrations below. Next, the latch will be closed to lock the yarn onto the hook. The locked, loaded hook is then drawn through the zipper tape. Once drawn through, the latch opens and the hook is removed, depositing the yarn loop neatly on the front of the zipper tape.

As you know, any two pieces of knitting COULD be attached by sewing, but there are also NON-SEWING ways of attaching knitting together. For example, if two pieces of knitting have open (live) loops, the three needle bind-off can be used to seam them together.  To seam together a line of open loops to a line of closed loops, or to seam together two lines of closed loops (closed loops=bind off edge, or cast-on edge, or side selvedge) you can use slip-stitching.

By using the knit-picker to insert loops (open OR closed) onto the surface of the zipper tape, you're turning the zipper tape into a knit-able object.  Once the zipper is knit-able, it can be seamed or attached to a piece of knitting just as easily as any other two pieces of knitting could be, with no sewing necessary.

There are two basic methods for inserting loops into a zipper tape--open (live) loops or a chain of closed loops. For open loops, you can simply pick up loops as you draw them through to the top surface of the zipper tape, then deposit them onto a knitting needle, as shown below.

Creating open (live) loops

In order to get a line of closed loops (a chain of loops on the surface of the tape) you pull loops up, each through the previous loop, leaving a chain of slipped stitches on the top surface of the zipper tape. These chain stitches provide the anchor for further manipulation.  As indicated above, the open-loop method is analogous to a line of live loops, while the chain method is more like a bound-off or cast-on edge, or a side selvedge.  Choose the method of drawing through loops depending on what your planned method of attachment will be.

Creating closed (chained) loops

NOTE: In the illustrations above, the latch hook is not to scale: in real life the hook and latch assembly is FAR, FAR SMALLER than shown. The head of a real knit-picker is tiny!

In both the open-loop and the closed-loop illustrations above,
  • "a" indicates the position of the latch hook--open to insert, closed to withdraw; 
  • "b" indicates the loops pulled through: looped over a knitting needle for the live-loop method, or chained onto the face of the zipper tape for the closed-loop method; 
  • "c" indicates the method of inserting the latch hook--directly through the zipper tape, then lifted onto a knitting needle for the live loop method; or through the previous loop and the zipper tape for the closed-loop chain method. 
In both illustrations, the green dotted line indicates the path of the yarn running under the zipper tape--both methods yield what looks like a neat row of running stitches on the back of the zipper tape

With the loops pulled through the zipper tape via the
live-loop method, this closed-bottom zipper is ready to be installed,
perhaps in the top of a purse, for example

Once you determine the finished zipper length needed (more on zipper length below) you count the number of rows or stitches along the garment edge where you will install the zipper. Mark off dots, one for each loop wanted, evenly spaced. 

Keeping the marks in a straight line is easy. Zipper tapes are usually woven with sewing guide lines right on them--a sometimes subtle, sometimes obvious pattern running lengthwise up the tape, shown as light gray dotted lines in the illustrations.

In the open (live) loop method, each loop will necessarily be the same size because they are caught around the barrel of a knitting needle. In the closed loop (chain) method, however, it is a bit more difficult. Because the barrel of the latch hook is tiny, drawing up each loop snug around the hook's barrel would over-tighten the loops. You can proceed freehand--drawing up each loop just so, as shown in the illustration, or for a more sure thing, you can temporarily insert a dpn of appropriate size into each loop as you make it, then snug up the loop over the needle barrel, then remove the dpn.  This makes each loop the same size, as long as you're careful to not over-tighten the slack away as you draw up the next loop. 

Zippers rarely come in the exact length wanted. To shorten a non-separating (closed bottom) zipper --the kind you'd install in a purse-top, for example--shorten it by working from the bottom, as shown:  First, sew a new stop.  Then, snip to length.  The snipped end is hidden inside the purse.

Sew a new stop (top picture) then cut 
(bottom picture) to shorten a closed-bottom
(non-separating) zipper

For a separating zipper--the kind you would use for a sweater front, for example--you can sew a new stop at each top in a similar manner, then snip away the excess zipper tape. Alternatively, if there's only an inch or so of excess at the top, simply fold the excess zipper out of the way at a 90 degree angle to the top of the garment, then sew the excess along the garment edge with the teeth pointing down. If you cut a nylon or polyester zipper tape, consider lightly heat-sealing the edge with a match: for safety, work over a sink with the water running, just in case the tape flares.


*Latch hooks take some getting used to. To control the latch's tendency to poke and tangle, use your thumb to flip and hold it it down (open) for insertion and again for yarn-catching, then snap it shut once it's loaded with yarn and before withdrawing through the zipper tape.

*Because of its stiff and inflexible nature, nylon or polyester zipper tape will fold over on itself along the line of the pick-up. With use and wear, the tape will eventually soften.  Washing first might soften an excessively stiff zipper tape.

*Although tiny, the latch hook can pull along yarns up to and including most chunky-weights. However, the thicker the yarn pulled through the tape, the more zipper-buckling you will get. To reduce buckling, create the loops on the zipper tape using a thinner color-matched yarn: sock yarn is perfect because it is both thin and strong. Alternatively, you can catch one loop through the zipper tape for each TWO stitches wanted. This reduced buckling by halving the amount of yarn inserted into the zipper tape. With this two-for-one trick, you must double the stitch count in the next row, perhaps by inserting a backwards (or forward) loop increase alternate with each loop on the tape, or working each loop as a kfb

*Whether you are working with a closed-bottom (non-separating) zipper or a separating one, it's best to pick up stitches with the zipper opened or separated: makes the work go easier.

*Poking the latch hook through a tightly-woven zipper tape goes quicker if you've used a large sharp sewing needle or small awl to pre-poke the holes.

*An INGENUOUS method of poking holes and getting perfect spacing at the same time involves using a sewing machine--but not to sew the zipper in.  Instead, you run the sewing machine blank (no thread) adjusting the stitch length to the gauge you want, and thus punching a line of perfectly-spaced holes in a straight line down the tape.  Putting a huge (like for sewing leather) needle into the machine makes the punched hole bigger and easier to see.  Thanks to reader Valsew for this tip.
* * *
Coming up: Knit-pickers aren't just for adding zippers.  They can be used to work in ends, also.  The next post shows how. 

Until next time, TK


Dana Strotheide said...

I love you so much! This is such an awesome tutorial. All of your tutorials are great, so informative and well explained. Keep it up!

Leslie said...

Now how did you know the husband has asked that the new cardigan I'm currently making him (steeking it as I'm in the round) have a zipper? I've been looking around and had thought I'd hand baste and try to neatly sew it but this looks neat! Plus I get to buy a new tool :)

Iryna Boehland said...

Thank you! This is a very cool idea! I was just ready for zipper installation for my daughter's cardi. I'll try it right away!

TECHknitter said...

Thanks for the nice comments--maybe come back and say if you liked it? Best, TK

Michaela said...

Great tutorial!
But: when the zipper gets broken, what will you do: throwing the whole sweater away?

fabstarfish said...

You are just fabulous. Every time I need a technical solution you have it. Or you have the link for it.
I have no idea what I will do if your website goes down.
I love you. In a very different way from the way I love my husband, of course. But I definitely love you.

Sherry in Idaho said...

54linkagriI have a neighbor who has a hemstitching machine. Would hemstitching work, to make the holes?

TECHknitter said...

Hi Michaela: You raise a good point, but I think the problem can be solved.

The most common problem is when the zipper-pull breaks. However, you can get replacement ones at fabric stores or on-line.

If you had to replace the entire zipper, you'd reverse what you did to attach it. Say you used a three-needle bind-off to attach the zipper to stitches you'd picked up through your cardigan front. Snipping a single stitch, then unpicking the bind-off will release the zipper.

If you started the garment from the zipper edge, removing the zipper is like removing any other cast on. TECHknitting has a post about length reassignment surgery for knitwear, and the principles would be the same.

However you release the zipper, once you have live loops again, you can attach another zipper in the same place.

Finally, while a sewn-in zipper is theoretically easier to replace, I believe you may run the risk of cutting the yarn as you hunt for the hidden and buried sewing-threads with your seam-ripper.

When it comes to zipper-replacement, perhaps it comes down to just which risk you prefer to take--snipping out sewing or unpicking knitting.

Hi Sherry--I'm not sure what a hemstitching machine is, or whether it would punch a series of spaced holes in a zipper tape, like a sewing-machine (run blank) would. If you DO try it, maybe come back and say whether it worked? I'd be very grateful to learn another method!

Thanks to all for writing--TK

Michaela said...

Many thanks to your explanations. There are good reasons to try the method on a doll's clothing.

quinn said...

Thank you for sharing another interesting technique! I may now approach a zipper with less hesitation.

When would you use the closed- vs the open-loop method? It seems more it stronger, or better in some way?

Thanks again!

quinn said...

Thanks - now I can picture the closed-loop a lot better. :)

TECHknitter said...

Hi Quinn-- The closed loop is, perhaps, a bit stronger, because there are several strands of yarn sharing the strain, rather than just one strand, as in open-loop. However, this is a minor factor, I believe.

It really comes down to knitter's choice, possibly based on appearance. See, if you pick up through closed loop so that the chain remains exposed, closed loop gives you the option to have an actual chain of a different color along the zipper edge. The chain effect, possibly in a different color, is not possible with open-loop. But really, it's just two different ways of doing pretty much the same thing.


stringplayer said...

Thank you for this, and your other great tutorials. A suggestion I learned in a sewing workshop: wash, soak or steam press the zipper tape before sewing it into your sweater to take care of any possible shrinkage.

JillD said...

I was going to do this on a baby cardigan but the separating zipper I bought had a thick plastic coating at the bottom of each side that made it impossible to get the knit-picker through. I'm not sure if all separating zippers have this, but it is something to watch for. (I ended up doing the moral equivalent of a "Hail Mary" pass and machine-sewing the zipper in; it worked out surprisingly well).

TECHknitter said...

Hi Jill D--I had a zipper like that on an adult cardigan, and ended up using a power drill (!!!) to make the two holes required in the plastic end. Since then I look for lighter-duty zippers if I can find them!

PenCraft said...

I used this technique with much success on a sweater for my husband. A couple of modifications. First, I taped the zipper to a board using masking tape. Then I marked equidistant spots on the masking tape where the knitpicker would need to pierce the tape based upon my gauge. Then, using a very small nail and hammer, I created tiny holes at each spot. I removed the tape and the zipper from the board and then followed your directions. It was super simple to deal with the bulky yarn because I didn't have to worry about working the knitpicker through the tape, it was all predefined.

TECHknitter said...

Hi Pencraft--thanks for sharing your technique, it is very clever! Best, TK

Iryna Boehland said...

Well... I tried and my knit picker couldn't go through the zipper tape. Good idea though.

TECHknitter said...

hi Iryna--I'm sorry to hear it wouldn't work for you :(

Would it help to watch Eunny's video?

New York Built said...

I was reading your slip stitch entry after reading this superb idea just to be sure I understood what you were referring to in the text of the two options for attaching a zipper. The thought occurred to me..."What if you could simultaneously attach a zipper and create the fabric fold to elegantly cover the zipper?"

Zounds, methinks I need to try! But first, I have all these other projects to finish...but just a swatch, for a diversion...LOL.

TECHknitter said...

Hi NYB--You BET you can do that! I haven't posted about it yet but I did teach it at a couple of seminars. Have a look at this post (about picking stitches up sideways) and you'll be able to figure it out PDQ, I'll betcha!

(cut and paste the linky into yr. browser window, I haven't figured out links in comments yet)

Best, TK

Infiknitwisdom said...

I am in the middle of trying this for the first time. I have the open loops on my zipper and haven't figured out a way to secure it to my garment so it looks appealing. I have open loops on my sweater opening that I tried a three needle bind off with and it looks like the zipper hangs off the edge instead of being hidden under the seed stitch edge band. I also tried picking up stiches where I picked up to start my seed stich edge and the zipper doesn't lay flat but instead rolls in like it needs to attach in two rows instead of just the one that is on the zipper to stop it from flapping back. Any feedback on successful applications would be greatly appreciated.

TECHknitter said...

Hi Infinite--could the loops be on the wrong surface of the zipper tape? Have a look at the two comments above yours for some ideas about hiding the zipper tape under a facing, too. If you like, you can send a photo of your progress to me at the e-mail address under "contact me" in the R sidebar, and we can take it from there. Best, TK

TESA said...

Muy buen tutorial. Muy buen blog
Teresa (de Pinterest)

Rebecca from ChemKnits said...

What an AMAZING tutorial! I've struggled to sew zippers onto knitting in the past because I've wanted to make sure it was secure. This would be easier AND more secure at the same time. Thanks for sharing!

Tomatish said...

Would you recommend using this method to attach lace-weight yarn to fabric? I'm working on a piece of lace that I want to attach to a silk pillow case, and I'm considering using this technique.

TECHknitter said...

Truthfully, I would consider sewing the top onto the pillow. It would be a lot less stressful on the lace.

Fi said...

I am going to try this on my Northmavine Hoody, quite looking forward to a new technique :-).

It has just taken me a long search online to be able to buy a tiny latch hook (i.e. not one used for rugs) in the UK, for any other UK people who need one the term here appears to be either a 'darning needle with latch hook eye' (Clover) or a 'feather hair extension hook' (various beauty companies). Available from the usual giant online retailer named after a river for about £3 - £5.

Gitte Winkler Knudsen said...

Hi, thanks for this tutorial. Is it ok, i link to this tutorial from my homepage in Denmark to yours ?

Best Regards Gitte

TECHknitter said...

Hi Gitte--Thank you for asking, and yes, I would be honored if you would include a link to TECHknitting blog on your Danish blog.

Best, TK

pradnya kulkarni said...

Hi.. Where can I find a zipper with holes on the side like you have?

roselie said...

I've picked up the loops and made the closed loop chain on both sides of the zipper, but the zipper seems to be pulling and curving. I thought perhaps the tension on the first half was to great, so the second side is very loose, but both zipper halves are doing the same thing. Anyone have a similar experience or know how to fix?

TECHknitter said...

Hi Roselie--sometimes, the zipper is just going to curve and act as if it were too long for the sweater. This is called "buckling" and even sewn-in zippers do it, even on mass-produced clothing.

If you search the internet for "zipper buckling" you will find this is a common complaint on sewing websites, and there as as many different proposed solutions as there are people asking for help.

I, personally, have resigned myself to the fact that zippers will buckle, and that's part of wearing a zippered garment. I'm sorry I have nothing beyond philosophy to offer. Regretfully, TK