Originally Posted by
JustAbitCrazy
One more tip: Sometimes when you load a backing one side sags. The easiest way to remedy that is to roll the backing back and forth a few times, all the way from everything on the takeup roller to everything on the bottom roller, keeping the backing taut the whole time. You'll see improvement each time you roll it until there's no more sagging. I don't know why that works, but it does. And I don't know why the sagging happens, either, but it does, lol.
I'd do this too - it has resolved the problem for me several times.
Also, one question I HAVE to ask - were the selvages removed before piecing the different parts of the back? Leaving the selvages in sometimes SEEMS like a good idea, but they really do mess up the tension and get the fabric out of square. If the selvages were left on the fabric, I'd remove them and re-piece these section. THEN do the "roll back and forth several times" thing... of course, once you remove the selvages, the problem may have been resolved.