Knits 101 Session 4: Prepping Knit Fabric

Okay, so you have your knit fabric, you've just bought it and you're ready to get to work with it. So of course you wanna prep your fabric before you sew it. I always recommend washing and drying and pressing it as you intend to use the fabric once the product is made or the project is complete. So if you're gonna be making a dress or something along those lines, you're gonna wanna wash it and dry it. Now, for years and years everyone has told me knits shrink when you wash them. And I have done a lot of different things to try and avoid their shrinking, but this time I went ahead and did a actual wash test. So the ones here in this bag, I washed in... First I washed them in cold water, and dried them on low, and nobody shrunk. And then I washed them in extra hot water and dried them on high. And you can see, they did not shrink. So I can line up sample after sample. The only one that did a little bit is this double knit here. And I have had double knits in the past that shrunk up, though it looks to me like maybe it didn't at all. But I have had double knits in the past shrink, so keep in mind that there's a chance that they will. And it also really depends on the fiber content. If it's 100% cotton, there's a good chance that it'll shrink a little bit, whereas more synthetics, they don't shrink as often. So as you can see, the washed ones sort of started to curl up more than the non-washed ones. If you don't... If you're... I mean that means you're gonna have to press them when you're ready to sew them. And if that bothers you, one option that I've had a sewing mentor give me a tip on is just go ahead and serge or overlock stitch the edges, the raw edges, not the... you don't have to worry about the selvedges, before you wash it, and then it won't roll up as much on you because those stitches will make the edge nice and sturdy. So if that's a concern, definitely do that. But in the end, none of them shrunk. So as far as I can tell, knits don't overly shrink when you wash them. But if you are worried that they might, always do a wash test. So that's basically what I've done here. You wanna cut two pieces that are exact same size, run them through the washer and dryer and press them as you intend to, and then compare size. And so with that in mind, you also wanna, again, refer to the fiber content for whichever type of detergent you wanna use. It might need a light detergent, or almost no detergent, or a very delicate detergent, depending on what kind of fabric it is. Okay, so if you're going to be sewing and pressing some knits, again, pressing you wanna look at fiber content and don't go above it, because synthetic fibers can melt often, so don't go extra high on the heat. And sometimes they can't withstand steam. Always start out cooler and work your way hotter with the iron as you are pressing, just to make sure that nothing's gonna go awry. You wouldn't want to ruin your iron. You also wouldn't wanna ruin your fabric. So bear that in mind as you're pressing it. And then if you are gonna be sewing anything with a seam that's going to have a of stress, so on my garment here, like the shoulder seam, that's gonna get a lot of stress just because it's the highest seam right here and it's going... The weight of the fabric pulls against it, and as I move, the dress moves, or the cardigan, whatever this is, moves with me and stretches as it goes. When you're doing... When you have a seam like that, you need to reinforce it. There are a couple of different ways to reinforce it, but primarily it's to put in some form of stay tape. So here we have a knit stay tape. If you wanna look at it, it's actually a piece of kind of knit interfacing. It's very light, may be hard to see. It's just interfacing that has been cut into these tiny strips. This one is sew on. You can also get fusible stay tape. I have also been known to use Steam-A-Seam when I need to adhere, when I need to fix up a seam and make it nice. Steam-A-Seam is sticky on one side and has a paper backing on the other side, and when you adhere it, it sticks to both sides nicely. And in fact, I will show you how you use Steam-A-Seam, and also how you might go about reinforcing a seam like that. So first you're gonna wanna cut a piece of Steam-A-Seam, or a piece of stay tape, that's the exact size of the seam you're gonna be doing. And you would wanna do it on both pieces of fabric where they meet, and you just wanna cut it to the exact size, so whoop. And I cut that little bit off and put it over here. And then this one, because it's sticky on both sides, you just press it on nice and neat, and the stickiness will just stick straight to my knit fabric. And then you peel the paper back. Ooh, there we go. And the paper disappears magically. And then you can see there's this line of glue up here. Now, if I was doing a seam, I would put the two pieces of fabric together, right on top, and then iron them together, and that steam is going to set the glue and make it permanent. Now, if I'm doing a hem, which is kind of what I'm sort of vaguely demonstrating here, I'm going to then fold this up. And you can fold twice and you can choose to put... If you were doing a traditional hem, you would fold twice, and then you would go ahead and fold one more time. But if you're just hemming with knits, they're not gonna unravel, so you don't have to worry about folding it twice necessarily. So if I fold it up once, then I would just go ahead and hit it with my iron. Now, the name implies steam a seam and that you do need steam. Some knits don't withstand steam as easily as other knits. Just depends on what they're made of. This one is fine with it. But it's plenty hot. So you can see that that is now adhered fairly well. In fact, if we put some steam into this iron, it will be more permanently bonded. But our iron isn't as hot as it needs to be, so we're gonna just assume that's what it would look like. So it would be up like this and it would be stuck permanently. And then you would just stitch right over top of where you put that interfacing, so that that seam stays nice and strong and it holds up to the stress of whatever you're doing. You wanna put that into shoulder seams. Collars are a good place. Arm seams, especially for athletic garments. And it's pretty handy and easy if it's sticky, to use it on a hem, because it's a lot like hem tape. It'll just stick it right up. Now, regarding interfacing specifically, when you're sewing knits you need to actually go out and seek knit interfacing. This is knit interfacing. You can see it actually stretches a little bit. Oh, not on that direction though. This way. And this is sort of a traditional... This is a pressed interfacing, but it's designed to be used with wovens. You can also get specifically woven interfacing. I've made two samples here. This one is made with the knit interfacing, and this is made with the woven. So as you can see on the knit, it stretches with the fabric as I move it around, and this stretches as it goes. And that's just gonna maintain the properties of that knit fabric as you wear it. But here on this one that has the woven, it doesn't stretch hardly at all, maybe on the bias just a little bit, which means that the knit is not going to stretch at all. You could use it if you were making maybe a belt or a waistband where you wanted to turn a knit into similar to a woven, and it won't stretch. But in general, when you're sewing knits, you need to leave that stretch in there, so that it'll flatter your form nicely, and it'll kind of move around as you move around, and it'll be way more comfortable. So those are interfacings. You'll see, on your pattern, often they'll call for interfacing, and now you know which type to get and you know where to put it and how to adhere it. You just follow the manufacturer's instructions to adhere it properly, bearing in mind fiber content of your fabric. Now, that's it for prepping our fabrics. I think we're ready to start talking about cutting our fabrics, so that we can move on to sewing eventually. So stay tuned.