silk | carpe diem!

This is what started it all. Spin Off Autumn Retreat 2010. A pile of dyed mulberry silk top and some felt discs on a table in Robin Russo’s class, and the comment that spinning your own silk embroidery thread and stitching a needle case is good fun. So I spun the silk using a top-whorl spindle to insert quite a lot of twist, used an Andean plying bracelet for the short lengths I spun, and used the embroidery stitches I could remember from my childhood. It was good fun. And that was my first gentle reminder that stitching could indeed be fun.

Disk of white felt embroidered with handspun silk flowers using chain stitch, stem stitch, bullion stitch and french knots in pink, blue, cyan, yellow and green.

I’ve used this needle case gently for the last 11 years and the silk threads are still in reasonably good shape.

250x view of blue handspun silk embroidered flower petals showing relative lack of wear. — 250X view of some stitches from the needle case to show wear of areas with less twist.

You may be able to see some slight ‘fuzziness’ indicating wear on the areas with very little twist.

Twist is good!
Twist locks the fibres in the yarn together to make a competent yarn: too little twist allows the fibres to slide within the yarn, which will then stretch under tension or even drift apart entirely (don’t ask me how I know this, it’s not a pleasant memory). But tight twist also means the fibres tightly spiralling on the thread are less exposed to wear in any one location on that thread. Tight twist locks the ends of fibres more tightly into the spun yarn.

But not always!
Uncountered twist makes a yarn — or in this case a thread — that is lively. Most stitchers either add twist or untwist their thread ever-so-slightly with every stitch; if you add twist, you’ll know it because your thread starts tying itself in knots. A lot of twist results in a thread that may not flatten and spread to cover the underlying fabric. It might even stay entirely round, which is good if you’re couching it down, not so good for satin stitch. Like cotton, silk can take a lot of twist before it becomes wire: on average, when in doubt, always add a little more twist to silk.

Choose a yarn structure: sample silk threads
I learn a lot by looking at and handling examples of things to understand how they behave.
In the image below silk threads are shown at 250x; they’re all from the same shot, split to allow me to name them. The white line indicates a 45° angle. [I’ve spelt ‘Gutermann’ incorrectly: it should be Gütermann. Sorry.]

Using a needle to unpick the thread and a jeweller’s loupe to see the result I can say the first three (1,2, and 3 in case of doubt) are all 3-ply threads. 4, the embroidery floss, is 2-ply. Why? 3-ply yarns are almost circular in cross-section, so they look much the same diameter regardless of how they lie on the fabric, whereas 2-ply yarn is roughly oval in cross-section: it has a flatter, wider side and a narrower side.
So a 3-ply sewing thread will make a more uniform line of stitches, and being circular and tightly-spun might even move more smoothly through the fabric. The 3-ply Sajou and Soie Perlée stand cylindrical, high and glossy above a ground fabric or other stitches to catch the light and provide structure to a design.
By contrast the 2-ply embroidery floss will lie relatively flat on its flat side and because it is relatively loosely plied (compare the twist angle) it will spread even flatter to cover more of the ground fabric.

5, the 2-ply handspun silk top, is almost as tightly spun as the commercial threads, it’s just a bit thicker. It’s relatively ‘fuzzy’ with a halo of ends around the thread by comparison with the spun reeled silks above it, but that is not proof that they are reeled and the handspun is spun from silk top: heat is used to burn that fuzzy halo off yarns mill-spun from silk top.

6 I will explain a little later.

Other factors to consider
Sewing thread and most embroidery threads (leaving aside those attached to the fabric by other threads) have to pass through a fabric multiple times. Fabric is hard on thread. Every slub will catch on the fabric, the leading edge of the slub will abrade more and fray and eventually fail. The slub will enlarge the hole made by the needle, damaging the fabric and leaving the rest of the thread a bit loose in that large hole.
So unless you want texture and are happy to live with the consequences, spin consistent singles and ply consistently. You don’t need a lot of silk to make a lot of thread, so buy the best quality silk you can find. Avoid clumps of short fibres, neps, noils and other annoyances if you can, otherwise pick them out of the fibre as you spin. Or accept the consequences: it’s unlikely to be fatal or even a disaster! Uneven silk thread works well in rustic textiles sewn in the boro tradition, even in relatively precise geometric figures.

There is significant variation in thread thickness and the amount of twist. Not my best spinning, but mottanai applies here: use what you have, waste nothing.
And it looks perfect appropriate, at least to me.

I have an example of silk embroidery in my historic textiles collection.

This is probably an envelope case to hold visiting cards c. 1720 (dated by the style of embroidery). Undyed linen (note that there are two layers, the outer being a much finer weave) hand-sewn and embroidered with yellow silk.

A slightly closer view of the embroidery including a view of the back because embroiderers always like to see the reverse. The flowers and other details are back stitch, with a simple wrap binding the edges of the envelope. The insert detail shows more clearly the sheen of the silk – after 300 years! – and the structure of the yarn, which is a 2-ply twisted floss.
And that’s why I tried Number 6 in the photo above, quickly twisting together a couple of strands of silk floss from Pipers Silks in the UK. It works, would work better if I used more strands for a thicker thread. But I’m not going to do that: I want to use that silk as it comes because it is so very beautiful and so very, very challenging.

I hope that’s enough to get you started. Use the best silk you have, spin evenly, spin reasonably tightly if not very tightly, it’s good fun!

SilkpHDamage3

“Protein fibres prefer acid conditions; plant fibres prefer alkaline conditions” is a truism that I’ve repeated myself on many occasions. It’s a commonplace when discussing indigo dyeing, as the vats are generally alkaline: indigo is more soluble at high pH. Warmth only makes things worse: hot alkali is said to cause damage faster than cold. Liles and others mention the risk posed by the vat fluid “Indigo vat fluid may be allowed to dry on cellulosic fibres but should never be permitted to do so on protein fibres, since the alkali becomes more concentrated as drying proceeds” ( JN Liles, 1990. The Art and Craft of Natural Dyeing. University of Tennessee Press).

In accordance with this I don’t allow the vat fluid to dry on my silk and wool; indeed, I sometimes put dyed goods into a citric acid rinse as soon as they’re cool, then plunge them into cold, thoroughly oxygenated tap water. The theory behind the cold rinse is that not only does this rinse out alkali not neutralised by the citric acid and oxidise the indigo compounds, it washes out loose indigo particles while they’re still truly loose, not dried onto the yarn or fabric to wear off later onto skin or other garments.

But I’ve been wondering exactly what damage alkali does, and how quickly the damage occurs. Should I be quite so paranoid when working with wool and silk, counting the minutes that the dyestuff is in the vat? I decided to investigate.

Bombyx aka Mulberry Silk seems more fragile than wool and therefore more likely to reveal damage. I took samples of commercial silk fabric, yarn, and Bombyx spinning fibre, tied them into bundles and submerged them in a 1-2-3 Fructose vat. I tested the pH of the vat at the start of the session and every time I removed a sample: it was over pH11 the entire time. The vat was maintained at 50–55°C for the duration of the test save for a brief overheating to something like 65°C for about 30 minutes between 2 and 3 hours into the test (I forgot to turn the gas off! Oh, for a water bath). The samples were removed from the vat, cooled slightly, then briefly rinsed in a citric acid solution (pH4) before further rinsing in cold tap water and air drying.

And this is the result of the test. From left to right:

Undyed silk; 30 mins; 1 hour; 2 hours; 3 hours; 4 hours 15 mins; 5 hours 15mins; 7 hours; 9 hours; 10 hours 45 mins (I had to go to bed, the next day was a gym day).

I think there’s a visible difference: after nearly 11 hours at 50°C or higher at >pH11, the silk on the end is less lustrous. As the photo suggests, it’s lost some of its drape, its flexibility. The difference is more obvious in the hand: that silk is ‘cottony’, it’s not as smooth as silk. So, that’s likely to be one aspect of pH damage.

To me, the most interesting thing is the time it took for the damage to be noticeable. (Note: the temperature peak 2–3 hours in is likely to have had some effect, but I don’t think it’s terribly significant – there’s no perceptible jump in the degradation at that point.) I can’t detect a difference between the undyed silk and that which was in the vat for an hour. I’m not even certain there’s a significant difference between the 1 hour and 3 hour samples; beyond that, the fibre does seem to be more cottony. The depth of the blue colour doesn’t change from 30 minutes, so there’s no benefit to leaving it in longer. It seems likely to me that the damage is cumulative, so caution is indicated when dipping repeatedly for darker colour, but still there’s far more leeway than I feared. I’m no longer going to count minutes and seconds when silk or wool is in a chemical vat for 15 or 20 minutes.

The colour change intrigues me. Again, the blue had a greenish tinge at 1 hour, so it’s not attributable solely to the temperature change. Is the alkali causing the silk to yellow? I need to try this again with washing soda and plain white silk.

carpe diem!

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Tag Archives: silk

Spinning thread for handstitching, Part II. Spinning silk.

pH damages protein fibres: a test.