Sewing knit fabrics-tips from Stonemountain & Daughter Fabrics

In September, Bay Area Sewists held a virtual meetup with Stonemountain & Daughter Fabrics about sewing knit fabrics. As the organizer for this Meetup group, I invited Stonemountain for a conversation about knit fabrics. Emily Gutman, one of the managers of this Berkeley institution, answered many questions and showed us various fabrics during our Zoom meetup.

Here are the questions I put together combined with queries from Bay Area Sewists members. Emily typed up brief answers in advance of the meetup, and I’ve expanded on her answers here. I didn’t really take notes during the meetup because I was also monitoring the chat for comments. So apologies, Emily, if there are any errors! Any sentences in the first person are my comments. All photos are from Stonemoutain & Daughter.

Knit fabrics at Stonemountain

Can you give us an overview of the range of knits you carry, what makes them different from each other (jersey, rayon v. cotton jersey, French terry, ponte, etc.) and their weight? For example, a lightweight knit is X oz/yd, a medium-weight jersey is X oz/yd, etc.     

Stonemountain & Daughter Fabrics carries a wide range of knits — everything from sweater knits and activewear with four-way stretch to jersey knits, ponte, and terry.

Here are some of the fabrics Emily shared during the meetup:

• Yoga Cloth
• 100% Nylon Swimsuit Lining
• Bamboo/Cotton Fleece
• 100% Merino Wool Jersey
• Arietta Ponte Knit
• Cotton/Modal Jersey
• Bamboo Rayon Jersey
• Heavy Ponte
• Ponte Leggero
• Micro Modal Knit
• Cotton/Spandex Jersey
• Organic Cotton Knit
• Speckled Sweater Knit

Lightweight knits are around about 150 gsm (grams per square meter); t-shirt weight knits are approximately 250 gsm; french terry weight varies and could be anywhere from 230 gsm to more than 300 gsm; and ponte, 230-340 gsm.

Stonemountain has a handy blog post “What is gsm means and how to use it,” with a chart listing the various weights for different types of fabrics and what type of garments are typcially made from them.

Knit fabric opacity

How can you assess opacity when buying knit fabrics? Is there a metric we can look at or way we can know how see-through or thin a knit is?

Generally, when there’s a stretch percentage listed, it’s how stretchy it is without losing opacity/design. Also, keep in mind that lighter colors will be more see-through. If you’ve got a lightweight knit print with a white background, it will likley not be opqaue.

You can always ask the store for a photo! But now that the store is open for in-person shopping. You can take a look at the fabric yourself — if you live in the Bay Area, that is.

Last year, I emailed Stonemountain to ask which knit print would be better for the Keilo Wrap Dress, including links to the two fabrics I was considering and I was advised that the print with the white background was a bit sheer, which was an excellent point. So I picked the other fabric. (Contact info for the store is here. They are very helpful and responsive.)

Measuring stretch percentage

How do you determine stretch percentage?

On jersey fabric, you’ll see that one side stretches more than the other. You’ll want to measure the stretch using the side with the greatest stretch. Then fold a length of the fabric so you are measuring the side with the greatest stretch. Hold one side of the doubled fabric at the zero mark on a ruler and hold the other side at the 10 cm mark. Gently stretch it as far as you can without the print getting too distorted or the fabric getting warped.

Each centimeter beyond the 10 cm mark is equal to 10 percent stretch. So if it stretches to 13 cm, it has 30 percent stretch, if it goes to 14 cm, it has 40 percent stretch, and so on.

Activewear has four-way stretch, which means it has equal stretch in both directions — vertically and horizonally. Think yoga pants.

Popular knits at Stonemountain

What are your most popular knit fabrics?

• Cotton/Spandex Jersey
• Bamboo Rayon Jersey
• Organic Cotton Knit

What knit fabrics tend to sell out more quickly than others?

Fun designer prints

What knit fabrics do you regularly stock?

Everything on list so far

Knits fabrics/patterns for beginners

What knit fabrics do you recommend for someone who has never sewn a knit fabric before?

Stable knits such as ponte or perla (cotton jersey), which are not as slippery, scuba knit.

What patterns do you recommend for people who are just starting to sew knit fabrics?

• Sweater pattern using a sweater knit, which is more stable
• Sew House Seven’s Toaster Sweater (paper pattern on Stonemountain’s site), link to PDF version on Sew House Seven’s website.
• Chalk & Notch Page Hoodie paper pattern; you can get the PDF version on Chalk & Notch’s website.
• Megan Nielsen’s Rowan Bodysuit & Tee; you can get the PDF pattern on the designer’s website. .
• Half Moon Atelier’s PDF Super Basic Underpants.

What are your most popular patterns for knit fabrics?

Sew House Seven’s Toaster Sweater (see links above).

I’ve made the Toaster Sweater (version 1) in ponte, french terry, and jersey, and version 2 in a double-sided knit so I made it reversible. 😉

Needles & sergers

What sewing machine needles do you recommend for sewing knits? 

Ballpoint jersey needle overall works but try out different types/sizes. Stonemountain has:

• Stretch Needles
• Ballpoint Needles 
• Twin Needles

Universal needles should work on some knit fabrics, too. But always test it first to make sure; sew on a scrap and see what happens to the fabric. Technically, universal needles are slightly rounded so they can sew knit fabrics.

If you don’t have a serger, can you still sew knits without having to worry about the seams?

Yes, use a stretch stitch (lightning bolt) or zig zag stitch. Because knits don’t fray, it’s OK to leave the raw edge unfinished.

At this meetup, I noted that if you use the stretch stitch, keep in mind that it’s difficult to unpick it. You may damage your fabric as you try to remove stitches. So you may want to make a mockup with similiar fabric before you sew with your fashion fabric.

Staff faves

What are the staff’s favorite knit fabrics and patterns for knit fabrics?

• Favorite knit fabric: 100% Merino Wool Jersey. Emily says this is great for underwear.
• Favorite pattern for knits: Briar Tee and Sweater by Megan Nielsen, PDF pattern available on Megan Nielsen’s website.

Stabilizing knits

How do you stabilize a knit while sewing? What do you recommend for sewing hems that don’t stretch out? I’ve tried Steam-a-seam and double needle but hem eventually stretches out.

• Go slowly.
• Don’t pull on the fabric.
• Don’t let your fabric hang over the edge of your sewing table and stretch it out.
• Adjust your presser foot pressure, less pressure on the fabric helps.
• Use a walking foot, which ensures both layers of fabric move evenly as it goes forward under the presser foot.
• Use clear elastic or stay tapes for stabilizing seams

I used to used a walking foot but then discovered that by reducing the pressure on my presser foot, I didn’t need to use the walking foot. Check your sewing machine manual to see how to change your presser foot pressure. Note: Some older machines do not allow you to adjust presser foot pressure.

For shoulder seams on knit fabrics, I stabilize with Design Plus super fine bias fusible stay tape. It comes in white and black. There’s “super fine bias” and just “bias” versions of the stay tape. If your fabric is lightweight, go with “super fine.”

For hems, I like Design Plus ultra-soft double sided fusible tape to hem knits, plus a double needle. It’s 3/8″ (1 cm) wide. Use an iron to fuse it in place. It’s double sided so one side has paper on it. You iron on the paper side to fuse it to your fabric, fold your fabric and the iron to fuse the other side to your fabric. And then you use a double needle to hem.

For curved necklines, try Design Plus super fine bias or bias fusible stay tape.

When is knit interfacing necessary?

When a pattern calls for it. Use tricot.

Knit quality and muslins

How can you tell if a knit will pill quickly? How can you choose one that is high quality?

Synthetics will pill, as will looser woven natural fibers.

The knits I’ve sewn that haven’t pilled are cotton jerseys (with a little lycra) and ponte. Rayon knits can be delicate and can pill so they need to be washed gently. I wouldn’t recommend putting rayon knits in the dryer or they will pill faster or just get worn out more quickly. But eventually, you will likely see some pilling in rayon jerseys.

I’m interested in learning what to use as a muslin for knit fabrics. If I use another knit, how will I know it will react in the same way as the target knit I want to use for the garment?

The knit fabric for your muslin needs to be same weight and same stretch as the fashion fabric you want to use for your garment. Using a fabric with similar content will give you a better approxmination of what the garment will look like.

Stretch thread, tension for fleecy knits

What are your thoughts on stretch thread when serging knits? Is it worth the extra money?

Stretch thread isn’t really necessary for a serger. But you can use stretch thread on your sewing machine, which lets you sew a straight stitch (instead of a zig zag) without the stitches popping. When you wind it in the bobbin of your sewing machine, wind like normal, and keep a longer tail.

UPDATE: I tried wooly nylon in the bobbin of my sewing machine and threaded my needle using regular poly thread. I sewed a straight stitch on my ponte fabric and it looked great. Having a stretchy thread on the bobbin means that your straight stitch will stretch! This is a nice alternative to a coverstitch machine, which I do not have.

Loading the bobbin was a little tricky. You have to hold the thread, sort of guiding it as it loads or the thread might start loading below the bobbin. That happened to me. So watch the bobbin as it loads and go slow!

What kind of setting on tensions is best for fleecy knits?

Fluffy = lower tension. Be sure to test the setting on scraps to make sure the stitches aren’t too loose or too tight. Every fabric and every machine is different

Cutting jersey knits

How do you cut out jersey knits that curl at the edges? Is there a way to have them lay flat?

Use pattern weights!

I recently got two substantial pattern weights from Wawak. They weigh nearly four pounds each and are made of cast iron. They are the heftiest pattern weights I have. When you use them, you know that nothing is going to shift.

Lining knits

What suggestions do you have for lining knit garments?

Swimsuit lining or lightweight cotton/modal jersey. Stonemountain carries swimsuit lining in white, black, and tan.

Random questions

One Bay Area Sewists member says she often makes knit pants like leggings, but not as close fitting using medium to heavy-weight ponte. However, they get baggy at the knees. She asked: What can I do about this? Is there another fabric I should use?

Use a knit fabric that has some spandex in it, which will have better recovery than a ponte. You can try yoga cloth, which has four-way stretch.

Another member said she was making a double knit skirt. She tried making pockets with an ity knit fabric but that didn’t work. She asked: Should I have used a woven for the pocket bag? 

A more stable knit for the pocket bag would be better but it all depends on what you’re using the pockets for — to put things in them or as a place to put your hands. It you use a knit fabric, they pocket bag could get stretched out if you put a lot of things in your pockets. You can use a woven fabric for your pocket bags.

Whew! You made it to the end! This was a long post. I hope you found it helpful. Please feel free to share your tips in the comments.