All About Wool Fiber and Silk
Protein fibers are those of animal origin. Wool fiber is the hair and fur of animals and silk is the secretion of the silkworm. Protein fibers have the ability to absorb moisture without surface wetting. The technical term is hygroscopic and is the reason for the superior comfort and warmth over synthetics. When the wearer goes from dry indoor heat to damp outdoor air, the natural fibers absorb moisture and generate heat.
Protein fibers hold their shape well and are wrinkle resistant; wrinkles will hang out between uses. Fabrics feel lighter than the cellulose fibers, like cotton and are also flame resistant. Protein fibers, especially wool, require some special care. The fibers are weaker when wet so handle carefully when washing and use neutral or only mildly alkaline soaps. Avoid chlorine bleach; it will damage fibers.
Natural dyers love the protein fibers – both wool fiber and silk take up natural dyes so well. Cellulose fibers like cotton require extra mordanting to dye well. Synthetic fibers, like the acrylics and polyesters will not dye with natural dyes – these will take chemical dyes, probably because of the similar petrochemical base.
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Wool most commonly comes from sheep but also from other animals such as goats, rabbits, quiviut, camels, llamas, alpacas, guanaco and vicuna. Some factors that vary between wool types include the staple or fiber length, the crimp and the fineness, or diameter of the fiber. Diameter is measured in micrometers (1/1,000 millimeters or 1/25,400 inch). Of the natural fibers, wool has the widest diameter range, from 10 – 50 micrometers (Cotton is 16-20, Flax 12-16 and silk 11-12). The coarser wool fibers are more appropriate for hard wearing products like carpets, while the finer fibers are used for clothing.
In purchasing knitting yarn, the important thing to know are the yarn thickness or gauge, its softness (or hand) and whether it's superwash or not. Superwash has been chemically treated so it won't shrink and felt. Of course, this should be avoided if felting is the desired outcome.
Spinners need to know more about the fibers they are going to purchase as they are available in a variety of types and forms, such as raw fleece, washed fleece, carded rovings, or combed tops. The more it has been processed, the more it will cost. It's fun and cost-saving to 'start from scratch' but it requires a bit of equipment for carding or combing. New spinners will find it easier to begin with some prepared fibers.
Wool is the best fiber to begin with when learning to spin, especially the longer staple length. Microscopically, the surface of wool is made up of many overlapping scales.
This gives a little grip between fibers when spinning, making it easier to control. These scales are also what cause wool to shrink and felt – they become enmeshed with each other. It is also what may cause wool to feel itchy to some people. Wool from merino sheep as well as alpaca and other exotic fibers have a smoother surface and are less itchy. Allergy on the other hand, is often a different issue than itchiness. Sheep have an oil called lanolin that itself may cause a reaction or trap other allergenic materials that bother some people. Compared to sheep wool, alpaca is considered hypoallergenic.
If you would like to know more about various sheep wools, go to
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