Textile Processes – Wool

22 Nov

There are a lot of different processes involved in creating a finished product, such as an article of clothing, from wool that’s still riding round on a sheep’s back. All of these steps have been automated in various ways during the industrial revolution, and various tools and techniques have been tried. Many of them are opportunities for small scale crafters to create unique and creative products, but also, many of these steps can be drudgery if carried out in large volumes without machinery.

So, lets dive into the main areas of wool processing to make fabric, and perhaps you’ll see some areas in need of open source technology.

1. Shearing: While electric shears are certainly faster than hand shears, sheep shearing remains a highly skilled trade which can probably not be any further automated.

2. Grading: Even within a given fleece there are a areas of fibre with different characteristics. The fleece is graded based on staple length, fibre thickness, crimp pattern and lustre.

3. Picking: Large contaminants are removed from the fleece, possibly by hand.

4. Scouring: A collection of fleece (presumably of a given grade), is usually washed to remove the oily lanolin and the dirt and smaller contaminants trapped on the fleece. Some hand spinners do not was the fleece until after spinning, as the lanolin is an effective lubricant for spinning, but this is not a common approach in mechanised processes. The fleece must be scoured prior to dying, and if it is not scoured prior to spinning, then some of the contaminants may not be removeable later. The tricky bit about scouring wool is that warm water, soap and agitation will turn the wool into felt, and it wont be spinnable. Instead, scouring is usually performed with soaking only, and minimal to no agitation.

5a. Carding: Carding is the process of breaking up the lumpy structure of the pile of fleece and mostly aligning the fibres. By hand it is done with two wooden cards covered in small wire bristles. The mechanical process involves the drum carder, which has the same bristles mounted on rotating drums.

5b. Combing: While carding gets the fibres roughly aligned, it introduces a lot of air in doing so. Carded and spun fibre creates what is called a “woolen” yarn (even if not made from wool), whereas combing the fibre with large combs until the fibres are more precisely parallel and more closely packed together produces a “worsted” yarn, which is less insulating, but stronger and shinier. Neither is better, but they have different uses.

6. Preparing the Sliver: The carded or combed fibre might need some preparation to arrange it into a long sliver of fibres ready for spinning.

7. Spinning: Spinning is really two operations. First, the sliver is drawn out (drafted) into a longer thinner sliver, sometimes so thin that it would break if it was handled in this condition, and then it is twisted. This creates a single ply yarn. In hand spinning, the drafting is done with the hands as the fibre is fed into the spinning wheel. When done by machine, rollers moving at different speeds are used to draft the fibre before it is spin mechanically.

8. Dyeing: Although listed here, dying can be done at almost any stage of the process, providing the wool is not covered in lanolin. Dyeing before spinning has advantages in that different coloured fibers can be combined to interesting effect. Dying the spun yarn is a common approach in commercial fibre processing, however.

9a. Knitting: Both woolen and worsted yarns have uses in hand knitting applications, however many fabrics we use are also knitted (by machine). Knitting gives good stretch, and when done by machine is perhaps more efficient on a small scale than weaving cloth, as the complexities of warping are avoided. Most T-shirts, for example, are knitted fabric. The downside of knitted fabric is that it can pull apart if a single end becomes loose.

9b. Weaving: Weaving yarn into cloth is itself a complex trade with several processes which use unique tools. Different levels of technology and complexity are available for different scales of production, from kitchen table to cottage industry, and right through to industrial weaving mills.

10 Fulling: Newly created cloth typically needs some further washing and preparation so that shrinkage can be managed, and also so that any movement of the fibres occurs in a predictable way. For many types of cloth, it is desirable for the fibres to felt together ever so slightly, caused by some water and agitation, in order to visually blend the individual yarns together and create a warmer fabric.

11 Napping: For fabrics where fuzzyness is not desirable, finishing the fabric might be performed by raising the “nap” (the fuzzy stray fibres) during the fulling process, and then cutting the nap off.

12 Sewing: Creating garments from cloth is perhaps the area of fibre processing which people are most familiar with. It can be done on a small or large scale, although it’s not mechanized to the extent that some of the above processes are. The affordability of commercially made clothing is more due to global wage inequality than it is to economies of scale.

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