Nadia's yarn assignment: Electrically insulated copper "yarn"
Above: Two types of yarn I made that were eventually combined to create a composite, electrically insulated yarn. The blue & red yarn is made from wool, and the yarn that spells out "yarn" is made from copper fibers.
Copper yarn + wool yarn = electrically insulated yarn
All of the conductive fibers/yarns I have used in this class thus far have not been electrically insulated. I wanted to make an electrically insulated yarn, as I often use electrically insulated wires as resistive heating elements in my research. By creating an electrically insulated yarn, I can possibly create intricate electrical textile elements without worrying about shorting any circuits.
Above are images of my final composite yarn that has an inner layer and an outer one: the inner layer is copper yarn made from copper fibers rolled together, and the outer layer is made of yarn spun from wool fibers. In order to completely cover the copper yarn--and thereby electrically insulating it--I wrapped the wool yarn around the copper yarn and made consecutive knots with it along the length of the copper yarn. Note: This method of wrapping the outer yarn and making consecutive knots to create a spiral pattern is common in "friendship bracelets" as well as hair wraps.
Even though the outer layer of wool yarn is completely and intentionally knotted, the composite yarn is still extremely flexible. Also, while the outer wrapping should be relatively tight, one can still squeeze between the loops to electrically connect to the copper core if needed.
Select properties of the composite yarn:
Diameter: 3000~5000 micrometers
Total length of yarn: 0.0285 meters (limited by ~1.2 meters of wool yarn made)
Ply: 2
Copper fiber length: ~50 millimeters
Wool fiber length: ~125 millimeters
Copper twist direction: not applicable
Wool twist direction: Z
Wool twist: ~3 turns per inch
Conductivity: ~0.04 ohms per inch
Denier: ~309,473 grams *extra
Individual component: Copper yarn
The copper yarn was constructed by pinching and rolling copper fibers together with my fingers. The original fibers as well as the constructed yarn are shown below. The diameter of the copper yarn is 750~1000 micrometers, and the total yarn length was 1.85 meters.
Individual component: Wool yarn
The wool yarn that was to be wrapped around the copper yarn was constructed via spinning. Below are two sets of images of my two attempts at spinning wool yarn. The yarn from my first attempt was too thick (the diameter was too large) for working with when I tried to wrap it around the copper wire. Therefore, in my second attempt at spinning, I took portions of the first yarn to re-spin a thinner yarn.
Images of the second, thinner yarn are below. Note that I needed about 1 meter of the yarn to create about 1 foot of the composite copper-wool yarn.
Initial concept & experience
I initially wanted to make spun "yarn" out of plastic grocery bags and cellophane strips/"fibers," and to crochet a new bag out of this new yarn. I could have easily crocheted something out of strips of plastic bags, but I wanted to create spun yarn, so I attempted to create a multi-ply yarn by "spinning" twisted grocery bag and cellophane strips together. The purpose of the cellophane would have been to help hold the yarn together, as it generally has nice adhesion properties. Images of the grocery bag and cellophane "fibers" I prepared are shown below.
After experimenting a bit with my plastic fibers, I realized that I could not easily create the type of spun yarn that I wanted to, so I decided to ditch the idea (for now) and to create an electrically insulated yarn made from textiles. (I also felt guilty about not taking advantage of the spinning and textile resources provided for the class.) In fact, when the yarn assignment was announced, I immediately thought about making an electrically insulated yarn, but it was not obvious to me how I could spin this type of composite yarn. I thought about dipping an electrically conductive yarn in a curable flexible polymer like silicone or wrapping the yarn in a non-conductive yarn (as I have shown here). However, I thought that wrapping 2 yards of yarn would be a really tedious task!
After confirming with Prof. Buechley that I did not have to make 2 yards of the wrapped yarn (as long as I had constructed 2 yards of the individual yarn components), I decided to make my electrically insulated yarn. I'm very pleased with the final composite yarn, though I could significantly improve my wool-spinning technique! The wool yarn was initially too thick and had too much variation along its length due to my poor technique, so I definitely hope to have more chances to improve my skills. In terms of creating the copper "yarn", I was very pleased with how easily the copper fibers would "stick" to each other, making it very easy for me to create a long piece of yarn.