Cotton and that Pesky Lower Shed
I weave tonnes of tea towels, which means I use A LOT of cotton. I think cotton is great and I love weaving with it, but it has some unique challenges. One of them is that pesky lower shed. You all know exactly what I’m talking about, in fact, I bet you are all groaning about it right now! I’m not gong to promise to solve all your problems, but here’s how I eliminate (mostly) that sagging shed.
First, let’s talk about why this happens. When the heddle is lifted to the up shed, the ends get a little stretch as they go up. When the heddle is lowered, the stretch is released. Yarns with a little bit of stretch in them can easily accommodate the slight changes. Cotton on the other hand has no stretch. So the extra stretch that is needed in the up shed results in a loose down shed. This is frustrating for weavers, especially for new weavers who wonder what they have done wrong. Here’s how I tie on and start warping and I rarely have a loose lower shed.
Tie on in neutral. When you tie on, make sure that the holes and slots form a nice even line of threads across the loom. (see pictures 1 and 2 below)
After tying on, weave in 2 warping sticks, 1 in the up shed, one in the down shed. Press them firmly into place. The lower shed will still sag, see picture 3 below.
Return the heddle to neutral and tighten up the tension. I use a very high tension. Don’t worry (too much) about harming your loom, I have woven hundreds, maybe even more than a 1000 tea towels on my Ashford loom and it works as well as it did when I first bought it. As long as you can raise the heddle to get the upper shed, you should be fine. Note the flat even lower shed in picture 4. Here’s a video
Generally, this solves the problem. Even if my lower shed is a little loose I will start weaving. By the time I have woven about an inch, the shed has almost always tightened up. If in the very rare case it hasn’t, place the heddle in the down shed. Slide a pick up stick into the shed behind the reed and slide it back to the back beam. Leave it in for the duration of the project sliding it back as far as possible each time you wind forward.
I recently used Yoga Cotton by Ashford. This cotton is designed specifically with this problem in mind. It has a nylon core that is completely covered with cotton. The 18% nylon adds just enough stretch to eliminate the sag.
Happy Weaving!
