A Stretchy Hong Kong Finish for Sweater Knits

This is an updated version of a post that was first published on May 12, 2014.

"Is it possible to finish seams neatly on a sweater knit without a serger?" That's a pretty frequent question I get asked. The answer to that question is yes!

You're probably familiar with the Hong Kong finish when used with woven fabrics. The steps for creating this finish on a sweater knit are similar. For the binding fabric I use micro mesh from Spandex World in NYC's garment district. This mesh is also available online. I've also used very thin (a.k.a. flyweight) cotton or linen rib fabrics from Mood Fabrics. I've purchased both of these at Mood's New York store. They may be available online, though I haven't found them.

I've never seen or heard of a stretchy Hong Kong binding on a ready-to-wear sweater. I do love the finish, however, and think it's perfect for your handmade cut and sew sweaters.

How to Sew a Stretchy Hong Kong Finish for Sweater Knits

Step 1. Cut the binding strips.

I cut the mesh one and a half inches wide and as long as the sweater knit edge I'm finishing. No need to cut on the bias; the micro mesh is already nice and stretchy and doesn't run or fray. Pictured on the left is the mesh strip I'm using for this demonstration. In my hands is a sample of flyweight cotton rib cut into a strip. The right side of the sweater fabric is shown below.

Step 2. Sew the seam with right sides together using appropriate settings for the sweater knit.

For this fabric I used a regular zigzag at 0.5 mm wide by 2.75 mm long, sewing with polyester thread and a ball point needle, as I usually do with sweater knits. There's a 5/8 inch seam allowance for this demo.

Step 3. Sew the binding strip to the edge.

Line up raw edges and sew 1/8 inch to the right of the seam line, at the half-inch mark in this example. Right side of the binding is facing down, if there's an obvious right side of the binding fabric. I stayed with the plain, narrow zigzag (0.5 mm wide x 2.75 mm long). Stretch the binding fabric just a little as you sew. This will help keep the sweater knit fabric edge from stretching out when completed. (Note: Theoretically, if you have an overlocker, you could complete Step 3 with the overlocker and then skip Step 4, though I've never done it that way.)

Step 4. Trim the seam allowance close to the zigzag you've just sewn.

Step 5. Fold the binding strip over the sweater knit fabric edge and pin.

Step 6. Stitch the binding down.

Keep it stretchy. In this case I used the 3-step zigzag (3.0 mm wide x 3.0 mm long) right on the binding since the cut sweater fabric edge is now protected from stretching. I'm sure most any stretch stitch would work well.

Step 7. Trim the excess binding width on the back close to the stitches.

Also trim extra binding length.

Steam the seam allowance to the side. Steam the right side too. And that's it!


You may be wondering why I cut the the binding strip so wide when I was going to trim it in the end. There are 2 reasons: First, the trim becomes narrower as it's stretched along its length. Also, I like to be sure I have enough binding width to comfortably stretch around the sweater edge and to sew that final pass.

A stretchy Hong Kong finish will work with many sweater knits, as long as the binding fabric is thin enough. If using this finish with a very bulky sweater knit, I'd sew the sweater seam, steam it open, then attach the binding onto each edge separately, instead of both edges together as demonstrated above. (See free download Taming the Bulk When Sewing Sweater Knits.)

This seam allowance finish is a favorite of mine, and it can be accomplished with just a sewing machine. I think it's prettier than many edges that are overlocked or zigzagged and trimmed, if you've got the time!


Frocktails and Foldover Elastic

Recently, when doing a Facebook Live in the Sweater Knit Sewing group, I discussed the Stretchy Hong Kong finish. (A Hong Kong binding is a very neat and professional finish for seam allowances. My Stretchy Hong Kong finish is a variation of this binding that keeps the seam allowances nice and stretchy on sweater knits.) Someone asked me if it were possible to use foldover elastic (FOE) to finish the seam allowances when doing this stretchy version of a Hong Kong finish. I replied that I didn't really know since I’d never tried!

Well... weeks later I tried it and I didn’t like it. I don’t have the sample to show, because I never quite completed the trial. It turns out that FOE is too heavy for that application!

I like the look of this elastic, however. It's shiny on one side and matte on the other. There's a line along the length where you fold it. The elastic happens to be in my collection of elastics, because I like to have FOE on hand just in case I have the urge to make some underwear. Tip -- It's excellent for finishing the edges of panties!

And the shiny side happened to go perfectly with the fabric I used for my official NYC Frocktails sweater! (Frocktails is the name for a party where local people who sew come together for drinks and tasty snacks in order to discuss sewing and anything else. I think the first one I ever saw mentioned on Instagram was held in Melbourne, but the good idea spread and Frocktail parties are now held all over the globe.) I machine knitted my very silvery, metallic-looking fabric with rayon yarn that I've had for over a dozen years.

Though too heavy for seam allowances, I realized the FOE is actually great for the bottoms of sweaters. The weight, which was bad for seams, helps keep the sweater down. You may know that Chanel jackets have chains at the bottom to weigh down the garment so it hangs properly. That’s kind of what the FOE does in its own way. I considered it for a neckline as well but I have yet to try it.

The sweater knit fabric is two shades of shiny gray, a simple 1x1 rib, so the fabric is the same on each side. The width I knitted is the width of the sweater. I used the neat selvages without any added finishing for the armholes and side edges. The loosely knitted rayon is relatively lightweight, even though technically it's not a fine gauge sweater. 

You can see the fancy hem and side seams in the gif below, as I try too hard to recreate the festive atmosphere of Frocktails at home with only watered down ginger tea and a wine glass.

The sleeveless sweater has side slits that reveal a two-tone underlining, added for stability and coverage, from waist to armhole. I attached the front and back hems with a button. It's essentially a "low waste" design in that the sweater is two folded rectangles attached at the shoulders and at the underlining side seams. The foldover elastic made an excellent finish for the bottom edges. I had no idea the elastic would work so well! FOE is a good alternative to bindings and bands made from self fabric. (Self fabric = trim cut from the same fabric as the main garment) and works with heavier weight fabrics than I imagined.

Some people apply FOE to garments by just folding the elastic over the edge and sewing, but I use a two-pass method.

Step 1. I trimmed the bottom edges to the curved shape I wanted.

Step 2. I measured the elastic along the front bottom edge (in this case front and bottom edges were of equal length) and then cut two of these.

The FOE I used is three quarters of an inch unfolded. Here it is pictured above an elastic that’s an inch wide unfolded. The wider elastic may work for a bulkier knit.

Step 3. I then folded and glue basted the ends of the elastic under about 1/2 inch, as you can see in the picture, top right edge. The elastic pieces were now shorter in length than the bottom edges of the sweater.

Step 4. Working with the public side of the sweater facing up, I placed the edge of the fabric right up to the fold line that runs down the length of the elastic. I attached the elastic to the fabric using a 3 mm wide by 3 mm long zigzag, stretching the elastic slightly to the length of each bottom sweater edge.

Step 5. Next I folded the elastic around the fabric and did a second pass close to the edge of the elastic with a “wobbly straight stitch” (a.k.a. a very narrow 0.5 mm wide zigzag, 3 mm long). At least that’s what I did with my test sample! On closer look at the final garment, I seem to have sewn this second pass with a straight stitch. Unfortunately many days passed between my sample and binding the actual sweater, and I must have forgotten what I'd done. Since I stretched the FOE slightly as I sewed, however, the bottom edge remains stretchy.

Below you can see the inside and outside of the bottom edge. Another day I'll experiment with an even thicker fabric and the wider FOE.

Special thanks to @sewmsboncha, @sophomorestudio@disewbedient, and @cmykat for organizing such a fun #nycfrocktails2019 and for giving me motivation and a deadline to complete my sweater.


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Luscious Sweater Knits Extra - Part 2

Last fall I shared a behind the seams look at my Washington Square x Toaster 2 sweater that appeared in an article I wrote for Threads Magazine (#200, January 2019). The article is also available online now. Please click through also to see the very lovely model wearing the cardigan pictured above.

As I’ve mentioned before, some of the techniques in my article are not ones traditionally used in the garment industry for ready-to-wear clothing. I’ve specifically adapted many of these methods for home sewing. Here’s a closeup look at the featured sweater in the article.

Named after the stitch pattern I developed a few years ago, the Providence jacket was my first time sewing this particular fabric, and I was delighted to have an excuse to work with my favorite kind of knit! Back when I was doing custom knitting, I produced this fabric in a lighter weight yarn. This more substantial version of the Providence sweater knit, however, was developed for sweater coats and jackets. As my knitting contractor says, Providence is “slow knitting and full of body”.

If it’s my favorite kind of knit fabric then that means it’s wool, bulky, and has a prominent stitch pattern. A bonus feature is that this fabric has very regular, finished selvages which can sometimes be used as a finished edge.

I designed the sweater jacket based on my own sweater pattern block. Providence is relatively stable for a sweater knit. No special fit adjustments were needed to my basic pattern to make it work for this fabric. The stitch pattern has a strong vertical element in the design. I redrafted the front right piece so that the cardigan would have a diagonal, asymmetric front opening. I then cut out the pieces to take advantage of those clean selvages.

When constructing the cardigan I folded the selvages back on themselves and stitched them in place to produce sturdy edge finishes for the front opening. In the picture below you can see the folded over selvage at the left edge. The hem is bound with self fabric, rotated so the vertical element is running crosswise.

For the tie at the neck, I used a wider strip of Providence rotated as with the hem binding. I folded the selvage over to cover the unfinished seam allowance at the neck and hand stitched the selvage down with slip stitches. Using the selvage allowed me to produce a less bulky seam since there are fewer seam allowances.

The rouleau “eye” is supported on the inside with a small patch of interfacing.

For the article I shipped the sweater (along with my raspberry pullover and numerous small technique samples) to Threads Magazine for a photo session. After the package was returned to me, I tried on the jacket again and have now decided to add a second closure just under the bust. The additional closure will keep the front opening better secured to properly show off the sweater's asymmetric features.


Just getting started cutting and sewing sweaters? Join the list to learn about my video series and online workshop How to Cut and Sew a Sweater.