Silk is a luxurious fiber, soft yet strong. It can be rustic or shiny smooth, takes dye brilliantly, and blends well with wool, alpaca, whatever you like! Read on for everything you need to know about how silk is produced and how to start spinning silk fiber.
Where does silk come from?
Silk is a protein fiber produced by silkworms, which were first domesticated in ancient China (sericulture). The silkworm species Bombyx mori is used for commercial silk production. The larvae eats the leaves from mulberry plants, then produces silk filament from its head to make a cocoon. Silk filament is made up of a double strand of fibroin, which is held together with a gummy substance called sericin (silk gum).
The cocoons are harvested and treated in a series of hot and cold immersions to soften the sericin and allow the unwinding (reeling) of the filament as a continuous thread. When the silk fiber still contains sericin, it’s called raw silk – it helps protect the fiber while being handled, and can be washed out with soap and boiling water.
Photo via Brandon Fick on Flickr
One cocoon produces about a kilometer (0.6 miles) of silk thread – about 2500 silkworms are required to produce a pound of raw silk!
Tussah silk is the wild type of silk, which is produced by silkworms not specifically bred for silk production. Rather than the pure white silk produced by Bombyx mori (cultivated silk), it’s more of a warm honey color, less uniform overall, and a little coarser than cultivated silk.
Photo via Laura Chau
Characteristics of Silk
Silk has very high tensile strength, which means that it can withstand a lot of pulling pressure along its length without breaking. That doesn’t mean that it’s abrasion resistant though! It produces a delicate fabric that needs a bit of care in handling to prevent damage.
Silk is the thinnest of natural fibers, and is lightweight and very soft. All types of silk take protein dyes beautifully, producing rich and vivid colors. Since silk is produced as a single strand by a silkworm, you could say that the staple length is a kilometer long! Silk blends well with a variety of other fibers like wool and alpaca, and when blending, the fiber can be cut to be closer in length to the other fibers for ease of spinning.
Dyed silk hankies, photo via Hedgehog Fibres on Flickr
Caps and hankies
Silk caps and hankies (mawata) are made from layers of cocoons that have been degummed, softened, then stretched and dried over a form (a square or bell). Hankies are probably the easiest way to begin spinning silk. You do most or all of the drafting before spinning, so when it comes time to spin, you can concentrate more on the twist and fine tuning.
The fibers are less slippery to spin, since they’re are not aligned in one direction as for combed top and can catch on each other. You might need to really pull to draft! In caps and hankies there are thinner and thicker areas, so the spun yarn will be more rustic than silk spun from roving or top. Check out this great tutorial on Knitty showing how to draft and knit with silk hankies!
General spinning tips
- Silk fiber sticks to everything! If you have “winter hands” like me, scrub with a glug of olive oil and a palmful of granulated sugar to smooth out catchy parts that will drive you bonkers while spinning. Use a smooth contrast cloth to protect your lap from stray fibers.
- Spinning from silk top or brick can produce very smooth, lustrous yarn when spun worsted. If it’s a little too slippery and keeps getting away from you, try spinning from the fold (link) – working with a small amount of fiber at a time will also prevent it from sticking to your clothes!
- Silk can take a lot of twist, and tends to want to be thin. If you’re newer to spinning and want to spin thinner, try using a wool/silk blend – the wool gives the fiber some grab for drafting, while the silk adds sheen and will allow you to draft thinner more easily. Keep the drafting triangle large, and your hands wide apart – it takes more force to draft silk than other fibers like wool.
- For drop spindles, use a fast spindle if you have one. It will add the necessary twist quickly, especially when spinning very fine yarns. Don’t spin very fine silk singles on a Turkish spindle though, so you might not be able to get them off the arms!
- On the spinning wheel, lower your brake tension so that the spun yarn pulls in less quickly. If your tension is too high, you’ll really have to hold on to prevent it from jumping onto the bobbin before the yarn has enough twist. A lower brake tension will also help you spin thinner singles.
- When plying, keep your bobbins tensioned and singles well separated. Silk singles tend to be very tangley, so keep an eye out for snarls that can get caught in the plying. DO NOT try to ply from two ends of a center pull ball unless you are very practiced (and willing to untangle)! Handspun silk tends to lose a bit of twist in plying and washing, so keep that in mind if you are trying to make a tightly plied yarn.
Silk is strong, luxurious, and a treat to spin.