How can something so lovely come from something so icky?? Ohhhh... I'm going to get emails from the insect lovers on that one. But you have to admit it's pretty amazing how one of the world's most luxurious fabrics gets its start wrapped around a pupating silkworm, which actually isn't a true worm at all, it's the caterpillar of a moth in the Bombicidae family. One cocoon contains approximately 1,000 yards of silk filament. One thread consists of up to 48 individual silk filaments. A very picky eater (similar to my middle child, who I believe subsisted on Goldfish® crackers for nearly a year), the silkworm's diet consists solely of mulberry leaves. Starting Monday of next week, we have a series of beautiful color-blocked pillows made with rich silk dupioni. We thought you'd like to know a little history as well as some tips and tricks for successful sewing with silk.
The history of silk
Sericulture, or silk farming, is said to date back to 27th century BC(BCE) China, and the use of silk was confined to China for three millennia. In fact, an imperial decree condemned to death anyone attempting to export silkworms or their eggs. During the majority of this time, the right to wear silk was restricted to the Chinese emperor, members of his imperial family and the highest dignitaries. Silk was also often used to make paper (another Chinese discovery).
Women striking and preparing silk, painting by Emperor Huizong of Song, early 12th century BC(BCE).
During the 4th century BC(BCE), merchants began bringing silk westward. We know its route as the famous Silk Road, 4,000 miles stretching from Eastern China to the Mediterranean Sea.The Greeks and Romans were early adopters and particularly enamored; silk was even used in the Roman Empire as a monetary standard for estimating the value of different products.
Around 300 AD(CE), sericulture spread to Japan and by 500 AD(CE) to the Byzantines and the Arabs. Eventually, the Crusades brought silk production to Western Europe where it thrived for years in France as well as many Italian states. In 1472, records show 84 silk workshops and at least 7000 craftsmen in Florence alone.
The Industrial Revolution led to huge advances in the mechanization of spinning and looming, causing a rise in the popularity of less-expensive cotton. Silk production was, and still is in many ways, a very specialized and expensive process. The advent of the Jacquard loom, in the late 1700s, increased the efficiency of silk production, especially silk embroidery.
Today, with hundreds of natural and synthetic fibers available globally, true silk is again a somewhat rare luxury good and China has regained its status as the world's largest producer and exporter of raw silk and silk yarn.
Silk: the Queen of fabrics
The shimmering appearance for which silk is prized comes from the fiber's triangular, prism-like structure, which allows silk cloth to refract incoming light at different angles. Despite its delicate appearance, silk is the strongest natural fiber known to man. It has numerous innate qualities and advantages:
- Because of its natural protein structure, silk is the most hypoallergenic of all fabrics.
- An all-climate fabric, silk is warm and cozy in winter and comfortably cool in summer. Its natural temperature-regulating properties give silk the paradoxical ability to cool and warm simultaneously. Silk garments thus outperform other fabrics in both summer and winter. Silk worn as a second layer warms without being bulky.
- Silk is highly absorbent; it can absorb up to 30% of its weight in moisture without feeling damp. Silk will absorb perspiration while letting your skin breathe.
- In spite of its delicate appearance, silk is relatively robust. Its smooth surface resists soil and odors well. Silk is wrinkle and tear resistant, and it dries quickly.
- While silk's abrasion resistance is moderate, it is the strongest natural fiber and, surprisingly, easily competes with steel yarn in tensile strength
- Silk takes color well; washes easily; and is easy to work with in spinning, weaving, knitting and sewing.
Bulleted Information courtesy of TexereSilk.com
The six most common types of silk
Silk yarn or fiber from which the 'sericin' or natural protective gum hasn't been removed is called 'raw.' The protective coating makes the silk stiff and rather dull and can attract both dirt and odors.
A type of silk fabric made from twin cocoons naturally bonded together. The bumps in the fabric, they're really called 'slubs', are the result of this bonding. Dupioni is often woven from two different colors of thread, giving it a shimmering, color-shifting appearance. Sturdy and substantial, it feels almost like taffeta. It's very easy to sew with and holds a crease well. However, it does not stretch at all so make sure your cuts are precise.
This is what comes to mind when most people think of silk. Charmeuse is a medium-weight weave; the front has a satin finish, lustrous and reflective, and the back has a matte crepe finish. It has beautiful drape and is a top choice for garment sewing. Even so, it is quite slippery, snags easily and is really too soft to hold sharp creases well.
Crepe de Chine
Another top garment silk, Crepe de Chine (French for "Crepe from China) is very lightweight and known for its 'pebbly' appearance, which is achieved by twisting some fibers clockwise and others counterclockwise then weaving these twisted fibers together. Both sides of the fabric look exactly the same. It doesn't ravel as easily as other types of silk, but can tear if not handled with care.
Very lightweight with a plain weave, a nice sheen and a smooth texture. This is one of the least expensive varieties of silk fabric. It has a graceful drape, but because it is so lightweight, it's not a good choice for anything fitted; the seams easily tear under stress. Scarves are traditionally made from China silk.
This variety is in the dupioni family of silks and its name comes from the Shantung province. Originally, the fabric was woven from wild silk but today's shantung is usually made from cultivated silk warp yarns alternated with heavier dupioni weft yarns. There is a 'tussah' silk, which is still made from the cocoons of wild tussah silkworms that eat oak and juniper leaves; this results in short, coarse fibers rather than the traditional long, lustrous strands. Shantung is firm and crisp, making it a good choice for projects with gathers or pleats. It does ravel very easily so all seams must be finished.
Sewing with silk
The following are good rules for all types of silk, but as with any tip or technique, test everything on a small scrap before you dive into the whole project.
Silk is prone to snags and pulls, so it is very important your scissors are super sharp and free of any nicks in the blades. If you prefer using a rotary cutter, insert a fresh blade.
Needles & Pins
A brand new, fine needle with a sharp point is best. Try a 70/10 or 60/8 size. Needles called "sharps", "quilting" or "Microtex" are good ones to look for.
Sharp and smooth are the watch words for your pins as well. You can find actual silk pins, but any fine, sharp straight pin will work.
Cutting & Pinning
Slippery, slippery is silk! Because of this, it is often recommended you cover your regular cutting surface with kraft or butcher paper then lay the silk over the paper. The grip of the paper helps the silk from sliding. Because of the slipperiness, it's also a good idea to always cut silk as a single layer rather than folded.
Pins can leave behind holes in silk, so if you must pin, do it within the seam allowance so any left-behind holes won't be seen on the finished project.
Oddly enough, silk thread is not your best choice for sewing with silk. It's not as strong as cotton or polyester thread. I confirmed this with our friends at Coats & Clark. They recommend the Dual Duty XP Fine thread for silk, which is fine enough to meld into the seam and not cause puckering, but because it's polyester, is stronger that a cotton thread this thin would be. However, the XP Fine is available in fewer colors, so a Dual Duty General Purpose is another good choice.
Fabric markers and chalk can sometimes be hard to remove from silk. Make sure you do a test mark on a scrap and try to remove it before making any marks on your actual cut pieces. If there's a problem, try tailor tacks, which are made by running a doubled length of thread through the fabric at notches, dots and other marks. Or you can mark pattern notches by making a tiny snip within the seamline.
Seam and fabric strength
If you choose a lightweight silk for home décor projects, you might consider adding a thin layer of cotton batting for extra strength and density. This is a particularly good idea for silk pillow covers.
In garment sewing with silk, if you have a seam that is likely to have a stress point (sleeves, crotch, pockets, etc) you can add what is called 'stay tape' over the seam. A couple sources I found suggested using the selvage from your silk fabric, which I thought was a great, free idea. You can also use a packaged twill tape.
Avoid fusible interfacings. Silk organza is a good alternative.
If you are still worried about slipping and shifting while you sew, layer strips of tissue paper or lightweight tear-away stabilizer over and under your fabric prior to stitching.
A flat bottom presser foot is best, and you can experiment with increasing the presser-foot pressure. Alway run several test seams first to check for pulling or puckering.
If your machine has a straight-stitch needle plate, this offers the best surface for any fine, thin fabrics... not just silk.
A shorter stitch length is normally recommended - try 2.0 to 2.5.
Always finish you seams to avoid raveling. A French seam or a serged finish are your best choices. If you have a serger, one suggestion is to serge ALL the raw edges of ALL your cut pieces. This helps in two ways, 1) it prevents raveling while you are working with the pieces, and 2) it pre-finishes your edges while they are flat and easier to work with. Because a serger trims and cuts simultaneously, you'll need to over-cut your pattern pieces to account for the trimming.
Caring for silk
As with any fabric preparation, it is important to pre-treat silk in the method you intend to care for the finished project.
Often, silks best retain their crispness and shine if dry-cleaned, so no pre-treatment is necessary. That said, many silks can be hand washed, using a mild detergent or baby shampoo, in lukewarm water. Rinse the fabric several times to make sure all soap is removed.
Rather than drying in the dryer, roll silk in a towel to absorb excess water, then iron the rest of the way dry on a low setting. If wrinkles are not an issue, simply lay flat to air dry.
Use a pressing cloth (you can make your own from silk organza) to protect your silk from heat and steam drips. Press the seams flat first, then press them open. Pressing them flat first kind of 'melds' the stitches into the fabric and you are less likely to have puckering.
Never use a chlorine bleach; it will yellow silk.
Moths will attack silk so keep your finished project protected... I think they must know we stole the silk from them!