Lesson Three – Tips and Techniques for Sewing with Knit Fabrics
Now that you have a basic understanding of the varieties and properties of knit fabrics and you have collected the necessary tools for the job, it’s time to power up your sewing machine and get started! I hope you have gathered a collection of knit fabrics to experiment with. Again, don’t worry if the fabric seems challenging, we’re not worried about a finished product today, just trying and learning.
Sewing with Knits Tip #1 – Don’t Stretch as you Sew
As we’ve learned, knits are stretchy beasts. It’s tempting to try to control the fabric as it feeds through your machine by pressing or pulling the fabric. Unfortunately with knits, if you stretch the fabric while you sew, the stitches will lock the fabric in it’s stretched out state, which will result in a “wonky” looking, misshapen hem or seam.
In the following picture, I let the feed dogs move the fabric along on the first hem, and I avoided pushing or pulling. In the second hem, I pulled and stretched the fabric as I sewed. You can see that the first hem is straighter and the fabric lies flat. The second hem is wonky.
Be sure to let the fabric feed through the machine with as little pushing or pulling from your fingers as possible. You’ll still need to guide the fabric to keep the stitching straight, but allow the feed dogs to do their job moving your project under the needle.
Sewing with Knits Tip # 2 – Know When to Zig Zag
Common advice for sewing knits is to use a zig zag stitch rather then a straight stitch. There are a few good reasons for this advice.
First, sometimes fabric that will not correctly feed through the machine without major stretching will feed more smoothly with a zig zag stitch. If you’re finding that you need to push and force fabric through your machine with a straight stitch, try switching to a zig zag and see if that helps. I have found a zig zag stitch to be particularly useful when sewing ribbed knit fabric.
The zig zag stitch is considered a basic “stretch stitch” (or elastic stitch). A seam that is exposed to a lot of stretching needs a stitch that will stretch with the fabric. If you’ve ever pulled a small t-shirt over the large head of a toddler, you’ve probably heard stitches “pop”. The popping sound is breaking thread as the knit fabric stretches and the “not-stretchy” thread in the seams breaks.
To combat this, seams that need to stretch should be sewn with a zig zag stitch instead of a straight stitch. Essentially, this allows the thread to lengthen when the fabric stretches rather then to break.
Using a zig zag stitch or other stretch stitch is vitally important when sewing knit clothing for people, because people move and clothing must accommodate movement without popping seams. It is less important when sewing doll clothes because dolls excel at standing still and popping seams are less of a concern. The flowy hem on the bottom of a knit doll dress isn’t going to need to stretch nor is the neckline of a doll tee that opens in the back.
That said, there are parts of doll clothing that definitely need to stretch. For example, the leg openings on leggings have to stretch over immobile dolly feet, so the hems must be able to stretch with the fabric. A zig zag or other stretch stitch must be used for the legging hems, or your stitching will break the first time you pull on the leggings. Also, if you are sewing knit doll clothes for a younger child, it might be wise to default to a zig zag simply because the garment may be subject to lots of stretching and pulling as the child dresses the doll.
I almost always use a straight stitch when sewing knit doll clothes for myself or other adult collectors, simply because I prefer the way it looks. But do take note of the zig zag stitch and use it where appropriate. There are many other stretch or elastic stitches, but even the most basic sewing machine usually has a zig zag setting. If your machine is more advanced, you may have several stitch settings appropriate for sewing knits. Check your manual for more information.
Sewing with Knits Tip #3 – Tissue Paper to the Rescue!
You guys. I love this tip! If you’re struggling with knit fabric, keep a few sheets of tissue paper in your sewing kit and your problems will almost surely be solved. Tissue paper is my favorite secret weapon.
Simply lay a piece of tissue paper under your project and sew the seam or hem as usual. When you’ve finished sewing, gently tear the paper away from your stitching. The paper stabilizes the knit and the fabric acts more like woven fabric as you sew. It’s amazing! I’ve used a paper towel or even computer paper in a pinch, but I prefer tissue paper because it tears away cleanly and without pulling the stitches.
This is a particularly handy trick when sewing the narrow shoulder seams on doll clothes!
Sewing with Knits Tip #4 – Saved by the Scrap
One of the trickiest parts of sewing knits is the first few centimeters of the hem or seam. Sometimes the beginning of the fabric will bunch up or get shoved down into the stitch plate. As I mentioned in Lesson Two, using the correct needle and straight stitch plate can alleviate these problems, but here’s another trick to add to your arsenal.
Keep scraps of fabric on hand to use as a “starter” for your hem or seam. Fold the scrap fabric in half to give it a little width and place it under your needle. Align the fabric you want to sew with the edge of the scrap, using the presser foot to hold everything in place.
Bonus Sewing with Knits Tips
- When making a narrow hem on knit doll clothes, I rarely use pins or stress out too much about keeping the hem measurement ultra-precise. For example, a common practice to finish the neckline on doll t-shirts is to fold the fabric under 1/4″ and sew in place. I don’t press the hem first, I just fold as I go, sewing slowly and from the wrong side. A little spritz of water beforehand will help the fabric stay in place as you finger press the hem in front of your stitching.
- As mentioned above, I almost always sew hems wrong side up. It’s so frustrating to finish a neat looking hem from the right side only to turn it over and discover that you’ve missed catching segments of the hem in your stitching. Sewing from the the wrong side eliminates this issue!
- I lengthen my stitch when I’m sewing with knit fabrics. I usually set my stitch length between 3 and 3.5 mm. This helps prevent bunching and stretching.
- Since most knit fabrics won’t unravel or fray, I rarely finish inside seams. I’ve also been known to leave raw edges on sleeves, necklines, and/or hems for casual style or layered doll t-shirts, tanks, dresses, and leggings. If you are sewing for young children, you may wish to take more care with finishing, but since my dolls just stand around looking fabulous, they can get away with fashionable raw edges. 😉
Experts, did I miss any of your favorite sewing-with-knits tips? Let me know in the comments section!
Homework: Are you ready to tackle an actual project and get some pay-off for your bravery? Our next lesson is a sew-along with knit fabric. We’ll be making a cute little top that will look great in a variety of fabrics and that can be finished with only FOUR seams! You can totally do this.
In the meantime, practice sewing hems and seams with fabric scraps. Try out my tissue paper trick with the most misbehavin’ knit you can find. I know I sound like a broken record, but we’re not seeking perfection yet. Make a bunch of wavy, wonky seams by pulling and stretching as you sew and then see what happens when you let the feed dogs take control. Try hemming without pins. The more you practice, the more confident you’ll feel when it’s time to sew “for real”. Practice is never a waste of time!
Are you ready to move on? Proceed to Lesson Four