How Silk Is Made

As talked about in A Piece Of The Silk Road and Madame Butterfly's Cocoon Pets, it took years of care, learning, and attention on the part of man for silk to be produced. The Bombyx mori has always been the one species common everywhere as man's silk producer. There are other kinds of silkworms in captivity in China and Japan, but they are not of much importance.

The Bombyx yamai, the silkworm of Japan, which eats oak leaves, furnishes excellent silk and there are many other kinds of silkworms that furnish a little.

Those that have been allowed to remain wild can fly about as well any any other moths. Only those that have been cared for by man lost the power to fly. If they could fly, they would fly away, and we would never know where to look for their silk.

Having traced the silkworm from the egg to the caterpillar to the moth. What of the silk, of which has been talked about so much? Here, we come fact to face with a little tragedy, for every silk dress that is made means the death of thousands of silkworms.

The life of the silkworm is ended when the insect has reached the chrysalis, or cocoon, stage. It is then in a state of topor and can have no sense of feeling.

Then the cocoons are all ready it is decided how many moths are needed to renew the supplies of eggs. Some of the best cocoons are taken for the nursery. The others are wanted for silk.

The reelers then steam them, plunge them into boiling water, or submit them to a high dry heat. This kills the chrysalis.

the reason why this has to be done is that, if life remained in the chrysalis, the latter would turn into a moth, and would then form an opening at one end of the cocoon out of which to creep, thus spoiling the cocoon for man's purpose.

The next step is to wind the silk on the reels. To do this the cocoon has first to be softened in water which is warm but not hot. The water dissolves the gum that binds the silk together.

When done manually, a person with skillful hands would then twirl the cocoons about with a light brush that catches the loose ends and causes them gradually to unwind. All that then has to be done is to simply undo the work that the caterpillar did. However, the silk so far is too fine to be wound in this state.

In the thinnest part of the silk is so fine that two thousand strands of it laid side by side may cover only an inch, while in the thickest part from six hundred to seven hundred would be required to make up an inch in thickness.

So, when the ends of the silk are discovered, the operator joins the filament from several cocoons together, passes them through a fine eye of glass or polished metal in a winding machine, and letter the cocoons remain in the water, winds away until all the silk that can be used is wound out from each cocoon.

As one cocoon is exhausted another is added so that there is no limit to the length of the filament. The silk is wound on a wheel, or a reel, and care must be taken to see that the strands do not stick to gather.

In Eastern countries and in some parts of Europe, machinery was developed that was quite simple, but even in big factories, the process is still the same.

Once the silk is freed from the cocoon and wound on reels, it is made into hanks, or skeins, and is ready for the manufacturer. Many processes follow. The silk has to be freed from all the gum remaining on it, for at present it has no luster such as we expect silk to show.

It then has to be cleansed by boiling to be scoured, and purified by acids. That is one way.

Another is to let the silk begin its own purification by a process of fermentation, which is done by shutting up the uncleaned silk in tanks containing soapy water in which it may lay for weeks. After that, then follow with all sorts of washings and finally a drying.

The silk may be woven just as it comes from the cleaning machine, or it may be doubled and twisted. Finally, the silk is ready to be made up into materials for clothing or other textiles. A garment of pure silk lasts a very long time, for there are very few things that wear better. Sometimes, however, a silk garment or a silk umbrella becomes full of slits though it has been used very little. This trouble usually arises because the dyeing and finishing have not been properly done.

So far I have described how reeled silk is prepared. However, silk prepared in this way is a continuous filament, but such silk makes up less than half the weight of the cocoon. The outer layers of the cocoon and the layers next to the chrysalis are not reeled. Then, too, there are double or imperfect cocoons, or those from which the moth has emerged prematurely and cut through the threads. Thus, producing threads that would be broken in reeling.

All of this would be called "silk waste," and formerly they were thrown away. Now machinery has been invented which saves this material. After a thorough washing, the tangled fibers are straightened, trash and foreign material are removed, and which is left is spun into beautiful silk thread in much the same way that cotton is spun. This spun silk is real, and for some purposes is as good as, or better than, reeled silk. For other purposes it is not so good.

Before World War II, Japan produced about eighty per cent of the world's raw organic silk. However, most of the weaving was done in the United States, France, Italy, and some other countries. Argentina also became a producer of silk textiles.

Chemists did extensive and mostly unsuccessful experimentation with the problem of making silk directly from ground up mulberry leaves, without waiting for the silkworm to convert the material.

Today, China produces over half the world's silk, followed by:

• India
• Uzbekistan
• Brazil
• Iran
• Thailand
• Vietnam
• Korea
• Romania
• Japan

Interestingly, Japan who once dominated the world market in silk, now produces the least amount. Another, interesting thing about silk is that by religious law, Muslim men cannot wear silk. However, silk is very popular for Islamic women.