Controlled Elastics

The goal of this project is to weave with elastics and gain an understanding of how weave structure affects the stretchiness of a fabric. I intend to weave three different fabric structures with varying levels of stretch. Hopefully, by the end of this project, I will have an understanding of how the type of structure can change the elasticity of a given textile.

To gain a starting point for understanding, I used a page from the book "Manual of Swedish handweaving," which mentions elastics in a section about "crepe structures." from what I gathered, a crepe structure has a somewhat ambiguous definition: a structure that has no apparent pattern and creates a rough texture. so can't anything be a crepe? why is crepe used in elastics? I honestly don't know but a good way to find out is to get on the loom, so I started weaving these three patterns shown above.

I started by weaving the structures mentioned before, but when I took the fabric off the loom there was no stretch in the fabric. This is because there is no tension stored in the fabric to allow it to "scrunch" when it came off the loom. The elastic can be stretched, but the non-elastic thread is already stretched to its maximum, so the fabric overall cannot be stretched. You can see this in the sample in the way that the textile is flat and doesn't have much shape. In later samples, you can see that the textile has a 3D texture because the elastic has pulled the fabric in on itself allowing it to be stretched.

The solution to this is to stretch the elastic as you weave, so once you take the fabric off the loom, it can scrunch down and become stretchy. The problem is, however, you can't weave with tension or it will pull the warps together and become difficult to weave. The way around this problem is with a device called a "temple." a temple is made for this exact problem, and keeps the warps in line. I don't have a temple, so I made my own with string and some weights. The idea is the weights pull the warp-ends out using a counterweight hanging off the side of the loom.

When I wove my experiments with the twills I ran into the problem at either ends of my warp. When weaving a larger twill, such as a 1-7 twill, I am missing as much as 6 warps at either end of the warp (circled red). Normally this isn't too much of a problem, but when applying tension with the elastic thread it creates a big mess on either ends of the warp. My solution to this was to add "selvedge" structures on either end to hold the structure. A selvedge can be any structure, but it ensures that you are picking the last warps and maintains the structure at the warp ends.

As I was analyzing these early crepe structures, I realized that maybe the level of stretchiness has to do with the length of the floats in a structure. To easily test this I used different-sized twill structures. twills have even-length floats, which allows me to test how float length affects stretch in a very controlled way.

The final swatch has three sections with elastic, with the top being the least stretchy, descending to high stretch. I think the result was fairly successful in varying the amount of stretch. If you look in the picture you can see the textile creates a fan shape where the bottom is pulled in more than the top. This is due to the elasticity of each structure. All three structures actually fully stretch to the same length, but what differs is their starting length. the bottom (most stretchy) has the shortest starting length, so when it stretches to the final length, it had to stretch a longer distance. The top section is a longer section, so it doesn't have to stretch as far to reach the final length.

So what actually affects the stretchiness of a textile?

From my testing, I think there are two main factors that affect the stretch of woven elastic fabric: float length and the number of floats.

Float length: As I learned from the twill experiments, the length of float can affect the stretch of the material. A longer float allows the warps more room to pack in on each other, therefore allowing the fabric to stretch more. This same concept is easy to see in the warp direction. a looser structure, such as a 7-1 twill, will pack tighter in the warp direction because the wefts can push in on each other. Whereas a tabby is a really tight structure that results in lose packing and more "airy" fabric.

Number of floats: This variable I haven't done enough testing, but I think the concept is the same as float length. Similar to float length, you can change the amount the fabric compacts by just having more or less floats. If you have less floats, only the floated parts will compact leaving the interlacements to be the same length. I think this is why crepes are common for elastics, because usually they have different float lengths, but the number of floats is consistent throughout the pattern.

A lot of this project was just figuring out how to weave with elastic and gaining an understanding of how structure affects elasticity. For the final, I would like to get a bit more scientific with measuring elasticity. My end goal with weaving with elastics is to make a woven ankle brace, so I need to get more exact with the performance of my woven elastic. If I can measure how much an ankle moves, I can tailor the textile to stretch the exact amount necessary for a given application. Hopefully, by the end of the semester, I have a prototype of a fully hand-woven ankle brace. (I'm going to regret saying that).