29 May 2012

Weighty matter

Another 6" woven, another half-turn of the cloth beam.

For the first time, I'm seeing a bit of wear on the warp yarns in the area where they are lashed to the shed rod. When the beam is turned and those points rise farther up the warp, I can clearly see a zone of slight fuzziness extending all across the warp surface. It's nothing to worry about, though, just the validation of my theory that frequent short advances are the best way to keep the fuzz factor down. Perhaps next time I shall advance after a shorter length of weaving. Since each half-turn of the cloth beam doesn't take up the whole 6" I have woven, I have a little extra web to take up anyway.

It's also time to lengthen the warp now. I've only done about ten weights' worth of lengthening so far, but I should easily be able to accomplish the rest tomorrow.

Here is one of those points at which I appreciate my tendency to cultivate repeatability in my movements. (Some would call it obsession or compulsion; I prefer to think of it as consistency!) Because of the way I chained the excess warp, I can maintain my same approximate weight arrangement by undoing the same number of chain loops in each warp hank. So far that's worked out really well, although I think I miscounted on one hank because the weight hangs lower in comparison to its neighbors than it did before I lengthened the warp. That will probably bother me sufficiently tomorrow, in the bright light of day, than it did around sunset today. I will likely undo that one and fix it.

But for the most part, warp lengthening is an automatic practice with a high repeatability factor. That means I can do it while there is pretty much any kind of background distraction: spouse, offspring, visitors, audiovisual media, it's all good. Perhaps I will be sociable tomorrow!

23 May 2012

The dance continues

(Warning: this one is very geeky.)

The piece is more than 25% woven now; last night we turned the cloth beam again. Another turn and it will be time to unchain and lengthen the warp.

Draw-in is now visible and obvious, since the recently woven web is now wound over a layer of previously woven web. It's about 1" narrower at each side now. I'm not worried about this from a construction viewpoint, because I figured in a 10% draw-in when I was making calculations. But it does mean the top corners of the chiton will have a slightly trapezoidal effect. Hopefully nobody will be looking at the top edge anyway.

During this recent period when I wasn't weaving on a regular basis, something happened to my understanding of the dance. I've now hit on a sequence that is a great deal faster than the previous ones I tried. I've just about doubled my most recently clocked speed for a "there and back again" pass. Now it only takes two and a half minutes rather than five.

Here's what I'm currently doing. I wrap the left selvedge, then put the penion through the natural shed. I use the comb to loosely beat the weft into place, still on the open shed. Then I wrap the right selvedge, and here's where it gets a little tricky. With my left hand I pull and hold the sinister (rightmost) shed rod. I place the penion on the natural shelf formed by the heddles. With my right hand I take the weaving sword and draw it through the countershed, clearing any sticky yarns. Then I put the sword under my left arm, pick up the penion, and put it through the countershed. I drop the first shed rod, move to my left, and repeat the process with the second shed rod. Then I move back to the sinister edge of the warp, drawing the tip of the sword across the threads as I go as if I were using a pin beater. This helps the countershed fall back into place so the original, natural shed is clear again.

I beat in sequence from the sinister selvedge. Holding the handle of the sword in my right hand, I put the blade in the natural shed at about a 45 degree angle to the fell, with the hilt nearest the fell at the selvedge edge. Then I lever the point of the sword upward with my left hand. When the flat of the sword meets the fell, I push up gently, just until I feel the weights moving. Then I step to my left and repeat the process. It takes from four to six such movements to cross the entire warp, depending on how the weft thread lies.

You'll notice here that in both passes I am beating from the attached toward the free end of the weft. This is a trick I learned while weaving rutevev tapestries. I usually use my free hand to adjust the weft tension while I beat in this fashion. Managing the tension in this fashion helps me produce cleaner, straighter selvedges with less draw-in than any other method I've tried. Beating this way adds some walking to the process, because it means I have to cross the loom (from dexter to sinister) twice: once after passing the second weft and again after I've beaten to leave the sword at the sinister end of the loom. However, the speed I gain by not having to manipulate the sheds as much more than makes up for it.

Besides, the weavers of the Classical literature all walked up and down at their looms. Next I should work on being able to sing as I go.

22 May 2012

1 + 1 = Too Long Away

I had a technical problem along about the time that family obligations spiked, which led to me eyeing but not touching the loom for a while. I'm back now.

The technical problem I experienced involved those selvedge yarns. While I had no trouble with their unspinning themselves, they did nevertheless loosen. The Navajo warp is so loosely spun that it slowly lengthened and eventually pulled apart. After I'd mended a selvedge thread for the third time, I decided to replace rather than repair.

First I needed a good replacement yarn. I found something at the local yarn shop that would serve: Kraemer Natural Skeins Eileen, a DK-weight merino yarn. It is tightly three-plied, soft but not at all delicate, and the appropriate off-white color of undyed wool. (After this project is over, I'll come up with some interesting way to use the rest of it; it's not a bad weight for nålebinding.) Instead of the two ends of Navajo warp per selvedge, I'm using two ends of this yarn per selvedge.

The second challenge was to replace the selvedge yarn. Using a tapestry needle, I tried threading one end up through the woven selvedges to parallel the Navajo yarn. The selvedges are in a wrapped technique (two additional turns of yarn between each pick), which means I had a lot of tiny weft loops through which to stick the needle. Standing on my little wooden stool and doing that was such fiddly work that I gave it up after an inch's worth. Instead, I anchored the new selvedge yarn around the warp beam, leaving a generous unworked end at the top. Then I weighted the new selvedges, put them where they belonged, and set the loom to rights.

When I remove the web from the loom, the first thing I will do is, as they say in the weaving magazines, "correct the errors." I'll start by threading that unworked end of each new selvedge yarn through the weft loops in a way that does not involve me teetering on a stool with arms outstretched leaning forward against thin air. (Tables are a grand human invention, and I wonder that we fiber folk do not make more use of them than we do.) Then I'll remove the vestiges of the old selvedge yarns. Then I'll fix any warp threads that have had to be repaired.

Oh yes, warp repairs. So far three warp yarns have broken. They all belong to one weight hanging at the back of the loom, i.e., they all come from the heddled back layer rather than the laced front layer. (I expected that broken warps would occur with the laced layer, which is secured firmly at a fixed point rather than movable, but so far that layer has held up beautifully.) The weight in question comes from the central point of the warp, the area where the two shed sticks overlap, the area I have to baby along with every change of shed. This area is subjected to more movement, stress, and displacement than the rest of the warp combined; it's not surprising that even this really high quality warp yarn is showing signs of wear. Fortunately, I have some experience fixing broken warps on my horizontal loom. The same principle applies here, so I'm not sweating it. If warps continue to break in that area, though, it could become a problem.

With about a foot of weaving done, I have to say that I'm not entirely convinced about the theory of using two short shed rods rather than one long one on a wide warp. My experience so far suggests it's more of a hassle than otherwise. The central two inches of the warp display a much looser sett than the rest of the warp, which is not surprising given how much more manipulation it undergoes than the rest of the warp does. Since I'll be working in that area to rectify the broken warps, maybe I'll also be able to ease the sett a little closer, drawing from the surrounding area where the sett is (naturally) a little tighter.

On the other hand, perhaps if both the rods were pulled at the same time, as by two weavers working side by side, it might be a fine solution. But for one weaver working alone at a wide warp, I'm just not sure this is the way to do it. But then, that was the whole point of this project, wasn't it? I'm looking for proof (or not) of concepts.