Fulling a rectangle

Fulling a knitted or woven rectangle presents special problems. It's very difficult not to end up with a curved hourglass shape. Maybe the middle threads get more even and regular abrasion? It'd make sense because the end threads are not getting rubbed by their non-existent neighbors so they're not going to full as fast or as well as the better situated ones. This is a problem because mostly when we make a rectangle, we want one as the finished product :-). If you're weaving some cloth you can figure the ends are waste and can be cut out, but that's an awful lot of work for waste if you ask me. And if you're knitting you definitely want to get the desired shape, even if it's a scarf that doesn't have to fit exactly.

So the way to get over that is to make sure no threads are lonely, in other words you make a temporary cylinder, full it, and separate it again later. This will ensure a minimum of waving at side edges, and even fulling all the way to the ends of the piece. This is true whether you're fulling carefully by hand (it's hard to rub exactly more and more toward the edges), or even more the quick and dirty way in the washing machine

If you're using fabric you're going to cut or finish otherwise, you can always try serging the ends together (even if the fabric is knitted). But I personally have problems with that method, I can't guess well enough what my serger's differential feed adjustment needs to be to avoid waving in the seam, which is really counterproductive. So serging may be best reserved for circumstances where you have a scrap to practice on, ie when you've bought some wool knit and not when you've handwoven a piece.

The easiest way is to baste the ends together with some yarn that's not going to meld into the final product. The leftover wool from the project is not going to do! Even a contrasting color wool yarn will be very hard to pull out. You need some nice slick cotton thread, large enough to be easy to pull out, so sewing thread is a bit puny, maybe mercerized embroidery floss or perle cotton? Nylon cord is also really good, even slicker than cotton. The thin cord that's often used to start or end knitting machine projects is perfect.

Full as desired, pull out the basting cord, and voila! Perfection. Nice when something so simple gets such nice results, eh?