I just plied my third skein! I intend on using it in my weaving as warp. Do I need to wash the skein prior to weaving or is the wet finishing I will do after the piece comes off the loom enough?
I hestitate to reply, because I just used my handspun in weaving for the first time! I did knit one small scarf using handspun too. Anyway, I was told to always wash the yarn after plying to help set the twist. If someone with more experience has a different answer, I defer to them.
Washing the skein before weaving would help the twist awaken, so if your singles had stale twist and your skein is acting overplied, when you wash it, the singles' twist is re-awakened and can more properly balance (one hopes, if that was one's goal, that is) the ply twist. It will also remove what it can of any hand oils that got introduced during spinning the yarn.
But the other thing I'd do, for warp at least, and probably weft too, for balance, is block the yarn out, dry it with weights -- so it's not so elastic and stretchy on the loom. I say this after *not* blocking a skein and mixing it with some commercial yarn on a warp -- boy howdy, was it hard to get a nice tension across that warp. But the only threads that broke, in the end, was the commercial yarn (at the selvedges, so really not its weakness or anything, just where I had it).
So in the scarf I just finished, which still needs to be washed and photographed, if I'd blocked my skein that turned out springy it would have been better? The yarn wouldn't go back to being springy (back to its normal state) after the scarf was wet finished?
I weave all the time with handspun and do not wet finish prior to weaving. I do not block. I do have plenty of stale singles that are then plied. I've never had problems with this. I just ply them to match a wet finished plied sample strand of about 6 inches. I really don't have any handspun yarns acting overplied (unless I do it on purpose :-)), so I don't understand amelia's experience.
In knitting, you want the yarn to be all fluffed out before knitting. It's just easier to get your gauge right and it feels better on the hands, having a maximum of springiness. In weaving, you want the yarns to sink in together after the web has been woven and you want the yarn to be at a minimum of springiness on the loom. Commercial wool weaving yarns often have oils in them which are meant to be washed out after weaving during the fulling process. Harrisville is a great example. They sell cone yarns with oils in them for weavers. They go out of their way to wash the same yarns and produce them in skeins for their knitting customers.
Tina - wet finishing will bring back springiness to wool. The fibers relax and return to their naturally kinky state! I do hope you sampled to the point of wet finishing before weaving? It's always a good idea to do, even with precious handspun.
I did sample, but just on a simple frame loom. However the scarf turned out great. Thanks for explaining the lack of a need for washing the yarn prior to weaving. I knew weaving yarns often have spinning oil in them, but for some reason I never made the connection to washing my handspun.