Can You Predict Fulling?
I am a relatively new and unschooled weaver and am delighted in the process, if not always the result.
I also spin and want to use some of my homespun merino (not washed in the skein) to weave and wet-finish to a light fulling when done. However, I have not found any source that tells how much shrinkage to expect when fulling a fabric. I know this will vary with the yarn used and processing time, but I need to know some approximate figures.
In other words, if I need to set the width to 12 inches and weave 9 feet, will I get a scarf that is only 6 inches and less than 5 feet long? I may need to spin some more yarn, depending on your answer. My yarn is a light fingering-weight 2-ply, and I assume the sett would need to be fairly open. I am undecided whether to use a commercial yarn for warp and my handspun for the weft.
Wrap a ruler very loosely and start with a warp sett (ends per inch) that fills 1/2 inch on the ruler. Err in the direction of loose. There is no way to know the sett for a wool yarn without working with the yarn first. You should plan to weave a little and then cut off and wash a small section to determine shrinkage and fulling and then plan accordingly. You can resley after sampling as long as your initial guess is fairly close (you might end up with a slightly narrower or wider scarf than originally intended, but you'll be close enough).
There are too many variables to know the shrinkage beforehand with accuracy: the degree of twist, the composition of the wool itself, the degree of fulling, and the desired hand. I would start with allowing at least 25 percent shrinkage to determine whether or not you need to spin more yarn.
I would definitely use the same yarn in both warp and weft. If you don't, the two yarns are likely to full differently.