Process of making gut strings

Written by Maaike van Dijk

Guts from animals have been used for many different things over the years. This material was already used by the Egyptians and later on the Greeks and Romans. It was mostly used for surgical sutures and later for the strings on tennis rackets and archery bows. Of course, the most known use of the gut is for strings on a musical instrument. [1]

Different animals

The most typical animal gut used for strings are those from sheep or lambs. Although over the years the guts (mostly a by-product from meat factories) from kangaroo, cattle, and water buffalos were also a possibility. [2] From the middle of the 20th century many manufacturers used beef gut instead of lamb or sheep. This change was primarily made because sheep gut is more expensive and harder to process with machines. Although it might seem a positive change it has negative consequences, mostly for the musicians using these strings. The beef strings are stiffer and less malleable. This makes the sound incomparable with the traditional handmade sheep gut strings. [3] This is the reason why the process of making sheep gut strings is still until this day a process done by human hands.

Process of making sheep gut strings

The process of making gut strings has been around for centuries, but the traditional and most successful way of making the strings has not changed a lot over all these years. Although some European countries use different ingredients or tools, but these are very small differences.

The obvious but maybe a bit sad first step is the slaughter of the sheep and recovering the guts. It is very important to recover the gut as fast as possible after the slaughter because the blood vessels that run through the intestine must be cut as close as possible to the gut wall. If this step is not done fast enough these vessels will break off which will create unevenness in the strings. This will bring the quality of the strings down a lot. After the guts are taken out, they are bundled up into groups of five or so and knotted in the middle. This is an easier way to transport the long material and will ease the tension on the material.

In the second step, the strings are at the string maker’s workshop. This step takes a very long time; the fermentation process. The gut gets put into cold water and stays there for one or two days. This is done so that the gut gets softer and ready for the next and hardest step, the stripping and crushing of the gut.

The way this third step was done back in the 18th century was on a wooden plank with a piece of cane. The string maker had to get all membranes except for the muscle fiber, off the gut. The outer layer had to get scraped off, but at the same time the center, called the mucosa membrane, had to get crushed (See figure 1 below) [4].

If this was done with enough power, the center would liquefy and flow out of the gut. Nowadays, very fortunately, there is a machine which can do this step for the makers, known as the crusher/scraper. After this, the gut is an almost see-through white material that needs to be sorted. Then the gut is stored in salt until the string maker is ready to work on them.

When the string maker is ready for the fourth step, he first must rehydrate the gut and wash the salt out, where it has been for days. This step is done by putting the strings in an alkaline solution (a kind of metal group in water). This is where different centuries and countries use different types of metals. In the 14th century, Lye was used, and later in the 18th century wine lees (in Italy) and potash (in Germany, England, and France) were used. Nowadays it is most common to use Soda ash.

The fifth step is splitting the gut in two or in some cases even more ribbons. This is done because the gut has an inner and outer circle with different lengths. These different lengths are important for the gut, because of the way the intestines are curved inside the animal so that the long intestine fits in the small space. This means that the outside of the gut is longer than the inside. So, when the gut gets stretched out the inside would have more tension, creating uneven tension through the whole string.
The gut is placed onto a rotating blade, by hand to split it into a right-hand and left-hand side. These two ribbons have different purposes; the right-hand side is used to create thin, treble strings, because of the smooth muscle fiber and the left-hand side is used for thicker strings.

When the gut is split it gets another bath with several different solutions that remove the fat and oils from the gut. This sixth step is a tricky one because the temperature and the quantity of the solution must be very precise, otherwise the ribbons can be thrown away. When this step is completed the right way, the ribbons will come out long, white, and translucent.

After this process, the ribbons are placed onto a twisting bench, preferably a dark surface (so the many ribbons are clearly visible). This is step seven. Here the string maker must decide the thickness of the strings because this influences how many ribbons are used. A bundle of strings gets tied to one end of a machine called the spindle (See figure 2 below [5]).

The other end of the string gets tight up at the other end of the machine. There must be enough slack on the string so that the string has enough room to twist to the required degree. In this step there are different outcomes too; thicker strings need more twisting than thinner strings. When the strings are spun the string maker guides the twisting string down the length by hand. This is done to make sure that fibers twist evenly. This step is a very important one for the string maker because the more the string is twisted the more the strength of the string decreases and the flexibility of the string increases.

The eighth step is drying the strings. While the strings are laying on a drying rack for several days, they get twisted a few more times. This twisting must be done in moist conditions. The tightening of the string with twisting (after this process is already done several times) is done because the string shrinks in diameter when it loses water, but gains in length. Then they dry on this same rack for a couple of weeks, after which they get cut in length and are now allowed to season for another couple of weeks.

The ninth and final step is polishing the strings. This step has changed a bit over the years. The traditional way of polishing was taking a pad with horsehair treated with some oil and pumice powder and rubbing it over the strings. This was in a way the equivalent of sandpaper, but more delicate. Although this step did not do enough, because the thickness over the length of the string was still irregular. This was already caused by the twisting process. The solution was to polish the string so, that the diameter became regular throughout the length. Later, in the 20th century, a mechanism was invented to form a regular diameter during the sanding process, instead of fixing this problem with the polish. (See figure 3 below [6]).

In this same process, some string makers add a liquid lubricant to prevent string dust and provide a finish. Unfortunately, this liquid is quite a fire hazard, so most makers use the traditional oil and pumice powder. [7] [8] [9] [10]

Conclusion

The gut string-making process may have changed over the years and will probably change even more in the future, but this process of making the traditional gut string with some minor modifications should be remembered and carried out in the present and future. If this process would have been forgotten in a few years, how would a musician ever have the full understanding of historical practice on these beautiful strings?

References

  1. catgut | cord. (n.d.). Encyclopedia Britannica. Accessed on the 17th of May 2022 at 15.16, from https://www.britannica.com/technology/catgut ↩︎

  2. Do musical instruments utilize animal products? (2017, 14th of march). PETA. Accessed on the 17th of May 2022 at 15.30, from https://www.peta.org/about-peta/faq/do-musical-instruments-utilize-animal-products/ ↩︎

  3. Schürch, S. (n.d.). The Sheep and the Violin Maker - Wild - gut strings. Wild gut strings. Accessed on the 13th of June 2022 at 11.17, from https://www.wildgutstrings.ch/en/about-wild.html ↩︎

  4. Inside of sheep gut. (n.d.). [Illustration]. Gamutmusic. Accessed on the 13th of June 2022 at 21.06, from https://images.squarespace-cdn.com/content/v1/545bb8dbe4b04f070d4e7f30/1447704289832-IIQJ4OMM7AHE61QQGSXG/image-asset.gif?format=750w ↩︎

  5. Spindle. (n.d.). [Illustration]. The Strad. Accessed on the 15th of June at 13.03, from https://www.thestrad.com/lutherie/gut-strings-a-strong-stomach-for-strings/13497.article ↩︎

  6. Larson, D. (n.d.). Sanding mechanism [Photo]. The Strad. Accessed on the 15th of June at 14.13, from https://images.squarespace-cdn.com/content/v1/545bb8dbe4b04f070d4e7f30/1447707900372-BIOD7USD4CLWK9UJ3MA8/image-asset.jpeg?format=1000w ↩︎

  7. Nex, J. (2011, 26th of August). Gut strings: A strong stomach for strings. The Strad. Accessed on the 17th of May 2022 at 15:05, from https://www.thestrad.com/lutherie/gut-strings-a-strong-stomach-for-strings/13497.article ↩︎

  8. Larson, D. (n.d.). Making Gut Strings. Gamut Music. Inc. Accessed on the 14th of June 2022 at 20.23, from https://www.gamutmusic.com/new-page ↩︎

  9. Aquila Corde Armoniche. (2021, 3rd of January). The historical Italian way to make gut strings from the whole unsplit lamb intestine: demo. [Video]. YouTube. Accessed on the 14th of June 2022 at 20.27, from https://www.youtube.com/watch?v=630xalYuGsI ↩︎

  10. Petros Biris. (2010, 5th of January). How natural gut is made [Video]. YouTube. Accessed on the 15th of June 2022 at 14.42, from https://www.youtube.com/watch?v=WCHkNko0OvI ↩︎