By this point in the semester we have the basis of a small industry whose primary motivation is the production of textiles. Sheep are being raised for their wool, wool is spun into yarn, soda ash, lime, and lye are produced to feed a soap industry, and the primary use of soap is to wash the yarn in preparation for dyeing. While these colored yarns may be used simply as tassels in primitive garments, they become even more important if the yarn is to be woven into cloth. There the colored yarns can be used to make patterns within the cloth which can convey status or social position. The device which weaves yarn into cloth is called a loom.
All looms start with a sequence of yarns called the warp which run parallel to each other the length of the loom. The warp may hang vertically with the bottom held in tension by weights (in the Greek, European, and Navajo tradition) or by stringing the warp horizontally in tension between two bars (in the Egyptian and Hopi tradition). Perpendicular to the warp threads, the weft is woven, over some warp threads and under others. The mechanism for quickly and easily inserting the weft threads is the principle challenge of the loom.
All looms attack this problem by providing a mechanism for lifting some of the warp threads while depressing others. This forms a shed, somewhat like the roof of a building, with some warp threads pulled one direction and others pushed the other direction. A single strand of weft is inserted into the shed, after which the shed is changed so that the pushed and pulled warp threads exchange places. Most modern looms accomplish this change of shed by means of a heddle. A heddle can be made of string, wood, or wire. Its primary purpose is to separate the warp into groups that can be simultaneously pushed or pulled to open up different sheds.
We will construct a particularly ancient type of loom which does not use heddles to change sheds. It is called a card or tablet loom. It consists of a warp attached to two end bars and threaded through holes in a stack of cards. The cards could be made from wood, leather, or clay but we will find it convenient to use cards made from plastic or cardboard. As the cards are rotated, different sheds can be opened. If the cards have four holes, four different sheds can be opened providing the ability to make complex woven patterns with ease.
The ability to weave patterns is one of the salient features of a loom. But for our purposes, it is much easier to weave simple stripes. If you would like to weave a pattern (it's not hard),you should definitely check out The Weaving, Spinning, and Dyeing Book on reserve in the library. It describes in detail the construction of a card loom as well as the warping of this loom to produce patterns.
There is really no new chemistry in weaving. But weaving motivated a lot of early chemical industries. Therefore, the weaving quiz is really more of a capstone quiz for all of the textile-related industries we have studied so far. It will consist of three questions on any of the following topics:
Construct a card loom from sticks, yarn, and cards. You can design your loom to operate vertically or horizontally, but it must have at least 15 cards and your woven belt must go around your waist. You can make your own cards or you can borrow cards from me with a deposit of $5.00/20 cards (exact change, please). If possible, you should incorporate at least one warp thread which you have spun, washed, and dyed yourself. The remaining warp threads as well as the weft can be taken from any source you choose, including yarn bought by the department for use in this class. When you are finished, you may return your cards and redeem your deposit.
What will be described here is a very simplified warp to produce a striped belt on the card loom. For a belt of two colors, you will need about 80 yards of each color plus another 80 yards of yarn for the weft. You can use any yarn, thread, or twine, but you should avoid the fuzzy kind of yarn used for knitting--it tends to be difficult to weave. You will also need two sticks and some cord for attaching the ends of the loom to a vertical or horizontal support.
You will need 20 cards. The cards I have are 3 inches on a side, but the size doesn't much matter. My cards are made of plastic, but the material doesn't much matter--wood, clay, slate, cardboard--anything really. Each card has four holes in it, labeled A, B, C, D. You can use cards with 3, 4, 5, 6, or more holes to weave different patterns, but I will describe the use of the 4-hole card.
----------- | A B | | | | | | D C | -----------
Begin by measuring out 40 pieces of yarn of each color. Each warp yarn should be exactly the same length (about 2 yards). Collect the warp as 10 bundles of four threads for each color and tie each set of four together at one end:
_________________________________________________________________ \ /_________________________________________________________________ X _________________________________________________________________ / \_________________________________________________________________
Starting with a bundle of the darker of the two colors, thread the warp yarns through the holes in the first card with the writing-side of the card facing the knot. Once this is done, tie another knot in the opposite end of the bundle, trapping the card in the bundle. Stretch the bundle out on the floor or table with a knot at either end and the card in the middle. Finally, lay the card on the floor, writing side up, with the A hole in the upper left hand corner.
-----------
========================|==A---B |==============================
\ / | | \ /
X SHED | | SHED X
/ \========================|==D---C |==============================/ \
-----------
The view here is to the face of the card stack, so we are effectivley looking at the edge of the cloth. Notice how the card separates the four warp yarns into an upper pair and a lower pair. The space between these pairs is called a shed.
Now prepare another bundle using the second weft color in exactly the same way and place it on top of the previous bundle. The two bundles should be as close to the same length as possible. Adjust the position of the knots if necessary. Continue preparing bundles until you have done half of them (10 in this example). The tenth bundle should be the lighter of the two colors.
For the eleventh bundle, select a light-colored one. Thread the card onto it so that the writing side is away from the knot and tie a knot in the other end as before. This bundle should look like:
-----------
========================| A---B==|==============================
\ / | | \ /
X SHED | | SHED X
/ \========================| D---C==|==============================/ \
-----------
The only difference between this bundle and the previous ones is that the
warp threads come up from behind this card rather than going in from the front.
Preapre the remaining bundles, alternating the colors, and adding them to the
stack. The final bundle should be dark in color so that the edges of the belt
will be dark and a double-width light-colored stripe will be in the center.
Now take two of your sticks and insert one into each shed. Tie a loop of thread around the bundles at each end to keep them from falling off the stick. Take the third 80-yard length of yarn (the weft) and wrap it around a piece of cardboard (the shuttle). Your loom may be strung vertically or horizontally. You may tie it between two chairs, hang it from the ceiling, tie it to your bed, or whatever you find convenient. However you string it, there will be a shed close to you and one farther from you. Insert the shuttle into the nearby shed (from now on THE shed) and lay down a single weft thread with the end hanging out. Pack this thread down into the shed and then rotate the cards clockwise 90 degrees. Just grab the whole deck of cards and rotate them as a group. This changes the shed and traps the weft thread between the warp threads. Bring the shuttle back through this new shed and pack the weft in with your fingers. Rotate the cards clockwise another 90 degrees. The shed changes again. Continue this clockwise progression of the cards until they return to their original orientation (4 turns clockwise). Each time you rotate the cards, insert a line of weft.
----->
-----------
=======================| D---A==|==============================
\ / | | \ /
XX SHED | | SHED X
/ \=======================| C---B==|==============================/ \
-----------
----->
-----------
======================| C---D==|==============================
\ / | | \ /
XXX SHED | | SHED X
/ \======================| B---A==|==============================/ \
-----------
----->
-----------
=====================| B---C==|==============================
\ / | | \ /
XXXX SHED | | SHED X
/ \=====================| A---D==|==============================/ \
-----------
----->
-----------
====================| A---B==|==============================
\ / | | \ /
XXXXX SHED | | SHED X
/ \====================| D---C==|==============================/ \
-----------
Then reverse the process, rotating the cards counterclockwise 4 times with a line of weft after each turn. Congratulations, you are weaving! Remember, in these views you are looking at the edge co the cloth.
<------
-----------
===================| D---A==|==============================
\ / | | \ /
XXXXXX SHED | | SHED X
/ \===================| C---B==|==============================/ \
-----------
When you get near the end of the loom, it will get difficult to change sheds. Untie the ends of the warp from the loom sticks and tie the loose ends together forming a fringe at each end. This will keep the whole thing from unraveling. Here is the side view:
\ /
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
/ \
Here is the top view of a two-color, ten card belt (+ is one color, o is the other):
=++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++= =o++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++o= =oo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oo= =ooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++ooo= =oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo= =oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo= =ooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++oooooo++ooo= =oo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oooo++++oo= =o++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++oo++++++o= =++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++=
This pattern for a 10 card loom would be produced by stringing the cards as follows:
ABCD 1 ++++ 2 o+++ 3 oo++ 4 ooo+ 5 oooo 6 oooo 7 ooo+ 8 oo++ 9 o+++ 0 ++++
i.e. card 1 gets + in holes A, B, C, and D. Card 2 gets o in hole A and + in holes B, C, and D, etc. When woven, this pattern is mirrored and then repeated to produce the pattern in the belt. You will decide on your pattern by deciding which colors go in which holes of which cards. And your belt will be 20 cards wide.
Once you get the basics down, you can make it more interesting in several ways. For one thing, instead of having each card strung with a single color, you can have different color warp threads in a single card. You can also experment with different patterns of sheds. What does it look like with 3 clockwise and 3 counter-clockwise. How about 8? How about 4c-4cc-3c-3cc-2c-2cc-1c-1cc? Have fun and see what you can make. The only real restriction is that you want to have the same number of clockwise and counter-clockwise turns over the course of your weaving, otherwise it will get twisty.
When you present your belt for evaluation, I will examine your belt for length and width. It must have at least 60 warp threads and must be long enough to circle your waist. If it is not, you fail. You may, however, try again (once per day) until you pass.