Many people here and there and elsewhere have expressed fear of sewing with knits. It’s not as difficult as you might imagine, if you adopt a few strategies ahead of time. Because people’s tools are a bit different, you might have to do some things differently than I do. I’ll list everything I can think of that might help you get started, and hopefully, others will chime in with their own tips.
1. Practice on an old, ratty t-shirt. You don’t necessarily need to spend anything to at least try sewing with knits. This might help you realize that you can, in fact, handle knit fabrics just fine.
2. For your first project, select a fairly stable knit. Don’t pick out a slinky, slippery, 4-way stretch fabric for your first project. Try a fabric similar to the t-shirts you wear, a knit with 20-30% stretch or so.
3. Kwik Sew patterns have excellent instructions for knit projects.
4. You do NOT need a serger to sew with knits, but they are nice.
5. If you are sewing with a conventional sewing machine, you’ll need to use a stitch that has a little stretch to it. I usually sew with a narrow zig-zag. I set the width to 0.5 and the length to 2.5. You could also use what is known as the “lightening bolt” stitch, which is very stretchy, but is the devil to pick out.
6. If your machine allows you to decrease the presser foot pressure, then set it pretty darned low. Experiment to see what works the best for you, i.e.which setting distorts your fabric the least.
7. Alternatively, or in addition to the presser foot pressure, you can use a walking foot.
8. When sewing shoulder seams in t-shirts, you’ll want to stabilize those seams with stay tape. Some patterns tell you to do this (Kwik Sew does) and some don’t. You’ll want to do it every time.
9. Hems can be tricky to make nice. I have tacked them up with Wash-Away Wonder tape, which holds the hem up and stabilizes the fabric while you sew. When you wash the garment, the tape will dissolve. Other times, I’ll fuse a strip of knit (tricot) interfacing along the bottom edge of the garment. The strip should be the same width as the depth of your hem. This stabilizes the fabric nicely, but does reduce the fabric’s stretchiness.
10. Needles! Needles can make all the difference. If you have super-stretchy fabric, you’ll want to use a stretch needle. If you have a medium stretch fabric, a ball point needle may be all you need. These needles won’t be as prone to damaging your fabric as others and may prevent skipped stitches.
11. For the hem, I either use the cover stitch function on my serger, which is cool, but I also regularly use a twin needle.
12. I learned this one the hard way. You must use a fabric that has the right amount of stretch for your project. You can find a gauge on the back of the pattern envelope. Basically, you fold over the crosswise edge of the knit fabric 3″ (8 cm). Hold 4″ (10 cm) of the folded fabric against the chart and gently stretch to the outer line.
14. Cut out your pieces using a rotary cutter on a self-healing mat. This is much easier than using scissors.
15. You might want to lay out your fabric and let it rest for an hour or more. Do not allow the fabric to stretch when cutting it out, i.e. don’t let it hang off the end of a table.