Friday, May 13, 2016

Pretty Fabrics Part 2: Grain and Stretch

Continuing our discussion of fabrics, we are going to talk about two things today: Grain and Stretch.

What is fabric grain? The short answer is the direction the threads in the fabric have been woven, or in the case of knit fabrics, "knitted."

It matters because if you cut your fabric off grain, you can end up with twisting, stretching or draping in your sewn garment when those things shouldn't be there.

Let's say you buy one yard of a woven fabric. And this fabric is a flannel and is 42" wide. Not all fabrics will be the same width. Quilting cottons are usually 44" wide, knits are usually wider with 60" being a popular width. But I digress. You will notice trends in widths based on fabric types the more you shop for them.

After cutting this particular fabric at one yard (36"), we have a rectangle which measures 36" x 42".

(This picture was taken after the fabric was washed, so it did shrink a little bit. You can also see how the edges frayed as this is a woven fabric.)

Here is said fabric:

I have labeled the selvage, cut edges, lengthwise grain direction, cross grain direction, and bias direction.

The selvage edges are the ones that weren't cut and didn't fray when washed, or frayed minimally. The distance between the selvages is the original width of the fabric, in this case 42". The edges that frayed are the edges that were cut off the bolt when you purchased your yard of fabric.

The lengthwise grain direction or simply sometimes called the grain is parallel with the selvage edges. There shouldn't be any stretch when you pull the fabric in this direction (in wovens.)

The cross grain direction runs perpendicular to the grain direction and selvage edge. There might be a little stretch or give when you pull the fabric this way. If it's a stretch woven, this should be the direction the stretch runs.

The bias direction runs diagonally across the fabric. When pulled in this direction, there should be a good amount of stretch. This is why you do not want to cut your fabric willy nilly, if cut on the bias you will get a lot of stretch and your garment will not hang correctly. These stretching properties can be used for good, however. For example, you cut the fabric on the bias when you want to make bias tape, which should have some stretch. Here is a link to a blog post about bias tape, we will not cover it at this time, but you can read more about it if you want to know more.

When using a pattern, it should specify which way the grain should go when cutting out your fabric. Line up this grainline marking parallel with the grain line on your fabric. We will talk about this again when we talk about using patterns.

If creating your own pattern, you will want to remember that any stretch in the fabric should go around the body. Just to get an idea of what I'm talking about, pull on your t-shirt, notice the direction of the stretch on the body and sleeves.

The fabric I used above was a woven, think of the threads in the fabric as threads in a wicker basket. They should be perfectly aligned at 90 degree angles like a perfect tiny checkerboard. But sometimes they aren't and get off grain. This is a great blog post for understanding what off grain looks like and how to get it back on grain. (Click on the link for more info.) For our beginner projects, this will not matter much, but it will once we start cutting bigger pieces and making apparel. This will be something to have in mind later. Don't let this information overwhelm you at this point, if you are like me, the best way to learn is simply jumping in, doing it, and learning from your mistakes. So for now, make a mental note of this and when you are more comfortable with the sewing process, come back and visit this later.

Now, we have been talking above wovens. Let's chat about knits too. The same terminology and labels still apply, but knit fabrics behave a little bit differently.

One difference is that in knit fabrics, the cross grain direction will have some stretch for sure. Some fabrics will also stretch in both directions, which is what is referred to as having four way stretch. If they only stretch horizontally, or across the cross grain, they are called two way stretch. These names confused me until I thought of it in the following way:

I had been thinking about it as two possible directions, horizontally and vertically, so once I figured that out mentally, it was an ah-ha moment. I was thinking, how can four way be possible? There are only two possible directions? Nope, I was just confused.

Don't laugh at me, we have all been there. I was also that kid who couldn't figure out my right from my left until I was embarrassingly old. Why does left change every time I turn around? See, my brain needs to figure these things out on its own.

Stretch percentages will matter too when it comes to selecting the right fabric for the job. However, we will cover this later when we learn about sewing with knits. I don't want to overwhelm you at the moment. It's not difficult to figure out how much stretch a fabric has, but not too important at this time in our series.

Another thing that is different about knits, is how to tell if you are truly cutting your fabric on grain. As it is not woven, the tutorial I linked above isn't quite accurate. Sure a good pressing before you cut out will be a good idea, but when you cut, you should take a close look at your fabric. Here is a very close look:

Do you see rows of lines? Those are your grain lines and what you should ideally line up your grain line markings in your pattern pieces. You can also tell that my fabric would benefit from a good pressing and being laid more straight before I cut it.

Here is the same fabric zoomed out, isn't it pretty?

Some fabrics, such as rib knit, will have very obvious lines. Some such as the one above, need a very close look.

Here is one more close look, this one is the purple one that is pictured up where we looked at the two way vs. four way stretch fabric:

One more look at the fabric at a regular size (my hand shows the scale.)

Finally, another difference with knit fabrics is that the cut edges will not fray. Some, but not all, will roll on the cut line.

When I first started sewing, I didn't know much about the grain line. I knew not to cut diagonally, but that was about it. As you start out, don't let this information scare you. Simply do your best, and learn from there.

This concludes our first week of our learning to sew party! Woo hoo! Next week, we will actually make some projects, I promise.

Your homework in the meantime is to find your manual. Look online if you can't find it. If you can't find the manual online, look on youtube for a video about threading your machine or any information you can find about your specific machine. If you really can't find anything, let me know. I will help or try to find someone who can.

In your manual, read the parts about all the parts on your machine and how to thread it. We will cover this on Monday, but you need to know how to thread your specific machine. Try to figure out how to thread it with your manual or a youtube video. 

I will be here to help first thing on Monday. See you there!

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