Knit fabrics are used for everything from casual athletic wear to elegant draped dresses. They're stretchy, soft, don't fray, don't require ironing, and come in a wide range of textures, colours, and prints. So why don't sewists just love them? Simple. Knits have a reputation for being a bit...tricky.
Some sewists will tell you that you need a serger or an overlock machine to properly work with knits, and you may have had your own struggles with wavy seams, misshapen projects, or tangled threads. While it's true that having a few speciality items can make it easier to sew with knit fabrics, there's no need to go out and buy a whole new machine. Here are a few tips for making the most out of your knit projects, and getting that perfect finish the first time!
1. Use a walking foot
A walking foot is a special attachment that's great for sewing all kinds of delicate and slippery fabrics, including knits. It adds a second set of feed dogs so that your fabric is moved under the needle from both the top and the bottom at a steady and even rate. This prevents much of the stretching and distortion that plague novice sewists when working with knits.
2. Support your fabric
Another way to avoid distorted seams is to support your fabric as you sew. With knits, the weight of the fabric draped over the edge of your sewing table can be enough to cause your seams to stretch and warp, so make sure there's plenty of table space to support your entire project.
3. Opt for a ball-point needle
The difference between knit fabrics and woven material is, of course, the way they're made. Knits are made by looping threads together, which means that instead of fraying, knits are prone to unravelling. To keep this from happening along seam lines, use a ballpoint need in your sewing machine. These blunted needles push threads aside rather than cutting through them, keeping your fabric intact.
4. Use a rotary cutter
Because of knits' tendency to stretch, it's very easy to accidentally distort them while pinning down your pattern pieces. Instead of pinning and cutting with scissors, use pattern weights to hold your fabric in place on a cutting mat and a rotary cutter with a fresh blade. If you're using a heavy or slippery fabric, opt to cut only one layer at a time.
5. Choose stretch stitch settings
While you can certainly use a serger for your knit fabric projects, your standard machine will also do a perfectly fine job, as long as you use the proper settings. For very sturdy knits with little stretch, a long straight stitch will do, but for most knit materials, you'll want to use one of your sewing machine's stretch stitches. The most basic of these, of course, is the zigzag, which comes standard on nearly every machine available. Test different stitch widths and lengths to find the right settings for your project.
6. Experiment with spray starch
Knits tend to roll along the cut edges, and while this can sometimes be a benefit—you can even opt to leave seams unfinished without worrying about fraying—it can also make it difficult to line up the edges of your pieces as you try to sew. Instead of struggling to flatten your pieces, keep them in shape with a touch of spray starch. There's no need to go overboard; start with just a bit, and add more as needed to keep your knits tame.
7. Account for stretch at collar and cuffs
When adding collars, cuffs, or bound hemlines, remember the cardinal rule of knits—they stretch! You never want your cuffs or collars to be the same size as the sleeve or neckline into which they're being set, but instead considerably smaller, so they hold allow the garment to stretch, but also hold their shape. When setting in collars and cuffs, don't stretch the body of the garment, but do allow the cuff to stretch to match the required circumference. When the seam is finished, the material will relax into its original shape, providing an elasticised quality to the sleeves and neckline.
8. Use tear-away interfacing for support
One problem with knits, especially lightweight materials, is that they tend to get drawn down into the mechanism of your sewing machine, especially if you're using a blunt ballpoint needle that pushes instead of pierces your fabric. Avoid this hassle by using strips of tear-away interfacing along your seams. This will help the fabric float under the needle and avoid causing damage to either your project or your sewing machine!
9. Press your seams
This one may sound a bit counterintuitive. After all, one of the great features of knit fabrics is their soft, draped look, which doesn't require ironing. Pressing your seams as you sew, however, has a different purpose. Just as with woven fabrics, pressing seams helps to set the fabric into its new shape and melds the stitches into a smoother line. Steam, when appropriate for the type of fibre in your material, can also help fabrics relax and return to their original state, which can help remove any lingering wiggles in your seam lines.
10. Test your sewing machine settings
This one may seem obvious, but it's important to remember with knit fabrics, especially if you don't frequently work with them. Knits require very different sewing machine settings, so while you may usually be able to get by from project to project with only minor tweaks, you'll want to make sure you're paying close attention when starting something made with knit material. Use scraps of your fabric to test your thread and stitch settings to make sure you're achieving the desired effect. You can even try different types of seams to see what will give you the finish you're after.
11. Use the right weight material
Just as with woven fabrics, not all knits behave the same. If your pattern calls for a lightweight knit with a lot of stretch, be aware that using a heavier fabric won't give the same results. Pay close attention to the type of fabric recommended for your project, and be sure check the specifications of any fabrics you're considering purchasing.