Tips on Sewing with Knits
In trying to keep my latest pattern concise, I’ve been struggling with what tips to include and which to leave out. Instead I thought I would post a bunch of tips I have learned over the years for working with knits. Many are found in some of my patterns, but I thought it would be nice to have them all written in one place, especially for my students or those who are new to sewing with knits.
My students will ask right away: How do I know what kind of knit to buy? I tell them to look at the content and make sure it has lycra or spandex–these are your friends. I feel the content is more important than the weight. I then tell them to pull and stretch the fabric. Look to see if it goes back to its original shape or does it stay stretched and odd looking. The ones that go back to their original look have what’s called recovery (recover their shape). The others sadly do not.
The type of knit does matter. Different types and even different weights of the same type will behave differently when you sew them. The quality of the knit matters, as well.
Contrary to what a lot of people may recommend, I do not like cotton interlock. I know a lot of people say start with interlock knit for newbies. I am not in that camp. I find it is fussy and finicky. It has limited uses in my opinion and its recovery is non-existent. If you do use it, make sure it’s a high quality fabric and it’s important that you know how to keep it from stretching as you sew. I have used it for yoga skirts (sewn to a tight rib knit waist band) and for hoodies. I rarely buy it anymore.
I like working with stretch knits and I recommend starting with medium weight cotton lycra knit. It is stretchy yes, but it recovers nicely, too. It is a stable type of jersey knit.
Jersey knits are single knits and some have better recovery than others. Thinner ones can be trickier to work with if you are new to sewing knits.
Stable double knits are easier to work with. Their edges don’t curl as much as single jerseys.
Still worried about it stretching as you sew? Jalie recommends slightly stretching as you sew. Eeek, I know.
A medium weight is also easier to work with (medium thickness). Don’t try a really thin jersey knit your first time out. It will roll and curl and you may get frustrated.
A lot of students ask me, “Well where should I go to buy knits that are better quality than Joanns?”
For my local students, I tell them go to the closest shops: the RainShed and the MillEnd store in Portland. That’s where I shop. It’s definitely hard to find local shops that sell high quality knits. Not everyone has a local shop. Joann is surprisingly expensive for lesser quality knits.
Chez Ami fabrics are among the easiest to sew with, though a bit pricy and their shipping costs are horrible.
Sewzannes has good quality jerseys and she describes their weight accurately. Prices are very good.
Etsy can be a good resource once you know which kinds you prefer. Many quality “quilt shop” fabric companies are now making knits and they are wonderful to work with!
There are some good brands, look for those. Just like with quilting cotton, quality makes a difference.
A lot of people recommend using a walking foot when you sew knits. The walking foot keeps both layers moving through the machine at the same rate.
I always use “stretch” needles**, not jersey ball point needles** and definitely not universal needles. I have never had a need to buy the jersey ball point needles in years, so I always use stretch needles- Maybe because that’s all I have on hand. Size 75/11 is for lighter weight knits, and size 90/14 would be for a medium or heavier weight fabric (thicker knit fabric).
**Jersey ball point needles are for knit fabrics without a lot of stretch, like cotton interlock. Stretch needles are a type of ball point needles designed for stretch knits and help to prevent skipped stitches.
A Teflon Presser Foot
I use it whenever I sew garments. It has a slick bottom surface, that allows it to easily glide over knit and elastane fabrics. Many machines come with one — check your manual 🙂
Add Stabilizer or Sizing
If I need a little more stability, I use Mary Ellen’s best press to the fabric and press it–especially if the edges are curling or rolling a lot. There are other products that are even more heavy duty, but I’ve no experience with them to share. I really have not needed that extreme help.
Tear -Away Stabilizer or Tissue Paper
For hems, necklines without binding, or other trouble areas, use some tear away stabilizer or tissue paper to keep it moving and looking good. Simply place a piece of tear away or tissue paper on top of the fabric and sew right on top of the stabilizer or tissue paper. After you’ve sewn what you need to sew, tear away the tissue or tear away stabilizer. This one works like magic.
The Twin Needle
Make friends with your stretch twin needle. Really. It is so easy to use, it sews a stretch stitch, and it mimics the cover stitch you see in store bought t-shirts. Just make sure it is a Stretch Twin (blue bar) and you know how to thread the machine. If the twin needle keeps breaking, more than likely you have not threaded the machine properly. See this post for how to.
You can use knit stay tape. They make a fusible kind now. I just use the regular stuff. It is especially helpful along shoulders.
It can be used in place of ball point pins. You can sew right on top of it and it washes out. Great for matching stripes placing a pocket just so before sewing it to a garment. I find it also helps to keep the 2 layers together and unstretched. It works fabulously to keep rolling edges tamed. It’s great for sewing gathered pieces to non-gathered pieces, like on skirts and dresses.
Loosen the Pressure of the Presser Foot
On your machine, you can loosen the pressure of the presser foot. This makes a huge difference! It’s usually a dial or knob. Your machine manual will tell you where and how to adjust this if it is capable.
My pfaff has a knob on the top next to all the thread guides. My Bernina has a dial on the upper left side–right next to the thread uptake lever. I reduce the pressure quite a bit when sewing any knit. For each fabric, I test on scraps until I feel it’s doing some good.
Straight stitches will break when the fabric stretches, so you need to use a stitch that allows for some stretching. In other words, you need to use a stretch stitch. It’s also recommended to stretch slightly the fabric as you sew — this gives your seam a little extra stretch.
A simple zigzag will do. The wider the zigzag, the more stretch the seam will have. On my machine, I use 1-1.5 width and 2.5 length for most seams and a wider width setting for hems. For bathing suits, I widen the stitch a bit for the seams, because the seams need to stretch more. I use between 3 and 4 length for the stitch length.
Rule of thumb: The wider the width, the more stretch the seam will have.
Straight Stretch Stitch (also called triple straight stitch): The machine will take 2 stitches forward, then 1 stitch back. 2 forward, 1 back across the seam, which creates a strong stretch stitch.
On the picture above, stitch #7 is the straight stretch stitch for this machine. Some machines have 3 lines as its symbol for triple straight stitch. Check your manual for which symbol it is for your machine.
Lightning stitch–looks like a lightning bolt. Nice stretch stitch to use if your machine has it.
Be sure to read your manual. It has great information to help you succeed in your sewing endeavors. Most will explain all the different stitches and their applications. For example,I have several stitches to choose from when sewing elastic directly onto the fabric. How cool is that?
If your machine does several of these stitches, then test those stitches on the fabric you are using. Remember all fabrics behave differently, depending on the type of fabric, its weight, and its quality.
Problems and Solutions
A Quick Guide
Does the fabric get shoved into the needle hole in the throat plate? Or do you get a mess of threads underneath at the beginning of a seam?
Hold your threads when you start. Start a little down from the very top edge.
When I teach kids to sew, I show them how to have the threads under the presser foot, to the back, and slightly to the left side before sliding the fabric under the presser foot. When they start sewing, I ask them to tuck the threads under their left hand to prevent the needle from becoming unthreaded or creating knots underneath. When you sew doll clothes and knits, you can hold the threads instead [you should really do this always, for all fabrics]. Holding them taut, even gently pulling slightly as you start sewing to encourage the fabric to keep moving-help those feed dogs do their job and avoid creating the 2 problems mentioned. [It also prevents thread tails from going where they are not wanted and getting in the way.]
Stretched out of shape
There are many techniques to prevent this. The first question I ask is: Is this Cotton Interlock? Most often, the answer is yes.
• Try using a jersey knit with lycra or spandex (about 5% or more) or a ponte fabric.
• Or utilize the ways listed above for controlling its stretch as you sew. Cotton interlock does not have much (if any) recovery. It just does not go back to its original shape after being stretched, so you have to sew it without stretching it.
• Lower the presser foot pressure to a fraction of what its normal setting is. Just be sure to put it back to its default/normal setting when you go back to sewing wovens or heavy weight fabrics.
• Use a walking foot.
• Place tissue paper or tear-away stabilizer between the presser foot and the fabric.
a little wave in the seams and hems when sewing jersey knit
Sometimes a small amount of wave will go away if you steam the area after sewing. If not, reduce presser foot pressure or other solutions in equipment section or the above problem/solution.
Rolling edges driving me nuts.
Use wonder tape.
Add starch or starch alternative on the fabric.
Pin close close to the edges, parallel to the edge of the area you are prepping to sew. (just be sure not to sew over pins!)
Cut and sew right away. The longer the cut fabric sits, the more it tends to curl. So cut right before you are planning to sew. Don’t let it sit for days or weeks. Knits are like veggies, it’s best to use right after cutting them.
Fusible tricot or stay tape can help with curling edges when hemming.
You could use spray adhesive to hold the 2 fabrics together at their edges. I’ve heard a lot of people say they use glue sticks. I tried it once. Only once. I didn’t care for it.
Skipped stitches or breaking needles
Make sure you are using a stretch needle.
Change your needle –should change your needle after 6-8 hours of sewing or every 3 projects at the least.
If it’s a twin needle that is breaking–check to make sure it’s a stretch twin and machine is threaded correctly. See this post
Why do people think sewing knits is hard?
I’ve come to the conclusion that it only takes one bad experience, especially if you are accomplished at sewing woven fabrics. I think the culprit is cotton interlock. Try a cotton interlock they say. In my early twenties, I worked at a quilt and sewing machine shop. The interlocks I bought there were a dream. I never had any issues. Never even really thought much about it. Just sewed happily.
It was about 5 years later that I had a bad experience. Really bad. I bought some cotton interlock at a cheapo store. It was garbage and not worth any amount of money. It gave me fits and refused to submit to my will –no matter what I did [though I didn’t know as much then as I know now. Isn’t that how it always seems to be?]. This was not only frustrating and time consuming, but it made me question myself, my sewing, and my choice-making skills. It took a bit of time before I thought about knits again.
Then I saw this brilliant Dr Suess jersey knit. Oh, I had to have it–it was begging to become clothes for my toddlers. One Fish, Two Fish. Red Fish, Blue Fish. I bought like 10 yards [yeah, maybe my choice-making skills had not improved much. In my defense I was living too near to a fabric outlet]. In any case. it sewed beautifully. no waves, no fussing or tantrum-ing, and no swearing or grumbling.
Comparing the 2 experiences, I realized that it had more to do with the fabric than anything. I needed to pay more attention to what kind of fabric I was working with and how to help that fabric behave the way I wanted it to. Buy only quality fabric. So if you’re new to knits, start with fabrics that are the easier to work with-those that have good recovery, a good quality, and are a little more substantial (no flimsy, see-thru jerseys, please). Test out some of the techniques in the equipment section of this post and practice. See what works for you.
As I’ve said before in other posts, you don’t need a serger to sew knits, especially knit doll clothes. Sewing knits is not hard or tricky, it’s just different. And as it is with most things, it may just take a little practice. Since the fabric is different, you need to sew it differently. That’s all.
Let me know if you have a question–I’m always happy to help if I can!