How can warping be done to prevent threads crossing at the back beam? And is it important to the overall quality of the finished piece to keep them perfectly straight?
I have three years experience of nonstop weaving on a Mighty Wolf, but warping hasn't become any easier. I warp front to back and back to front, but find back to front a more economical use of yarn. I use a warping board but seldom have a totally successful cross. My threads crisscross at the back beam whether using single or a few colors, but since I have a clean shed, I begin weaving. And while I think I haven't experienced any problems in my final product, a well-trained, accomplished weaver may say otherwise, and warping very fine threads remains too scary for now.
How do I warp many different randomly placed yarns without their crossing at the beam? Or is this when a sectional beam is needed? I was first shown to cut and tie together different yarns at the warping board, which works when they are few and occasionally spaced, but seems unwieldy and wasteful otherwise.
The good news is that there is no reason to worry about threads crossing at the back beam. In fact, it is perfectly OK to beam a warp through a raddle only, in which case the threads can cross each other quite a bit as they pass through the 1/2 or 1-inch space in the raddle. The reason this is OK is that when you are weaving, tension on the threads straightens them in the space between the back beam and the fell of the cloth (as you have actually observed).
If you use back-to-front warping with fine threads, I'd recommend beaming through a raddle only (you can put lease sticks in the cross made by groups of raddle threads—or not) with the threading cross at the other end.
An advantage to front-to-back warping is that you can wind several chains of different colors and place them randomly in the reed (no cutting and tying at the warping board). Again, it won't matter if those threads cross each other at the back beam, either. You'd rather not have a thread try to go from one side at the back beam to the other side through the heddle, but that shouldn't happen no matter how you warp.