Bobbins, Selvedges, and a Trapeze
I read the very interesting "The Quest for Weaving Perfection" on Weaving Today, and I have a couple of questions. I'd like to know why having a rock-hard bobbin would take care of weft draw-ins and by the same token obtain nice selvedges? I have also heard better warp tension can be achieved by using a trapeze. Can you tell me how a trapeze is used for this?
I didn't write "The Quest for Weaving Perfection," so what I'm giving here are just my own warping and weaving preferences. A tightly wound bobbin makes sure that as you throw the shuttle, the thread wound around the bobbin can't pull into the mass of other threads wound there, which it could do if the bobbin were wound loosely. If the thread pulls into the other threads, the bobbin stops unwinding, which stops the shuttle and yanks on the selvedge. The best selvedges are formed when only the pressure of the smoothly untwisting bobbin pulls on the weft as the shuttle is thrown, not pulling in too much, but pulling enough to take up weft slack at the turn. It's also important that the thread be wound on the bobbin smoothly, without any lumps. If the unwinding thread comes to a lump of threads on the bobbin, the bobbin also stops unwinding, again yanking on the selvedge. So the rule of thumb for winding a bobbin (just as for winding a warp) is: tight and smooth.
I am not a fan of the trapeze, though I know many weavers use it and love it. Google "Warping Trapeze" and you will find examples. It is a rod, parallel to the floor, that is suspended by side pieces way above the back beam of the loom. You attach weights to the warp chains at floor level and then turn the beam, pulling the weights to the top of the trapeze. Then you remove the weights and reattach them at the floor and continue until the warp is completely beamed. To me, it's a piece of equipment I have to have space for when it is not in use, and it requires me to attach and reattach weights. I prefer pulling on bouts at the front of the loom as I beam, where I feel I have greater control on the degree and evenness of tension.