What Are Piano Strings Made From?

It’s often easy to overlook the power of a piano string. Every acoustic piano uses strings and they are some of the strongest, most hard wearing and intricate strings within the musical world.

Every single time a piano key is pressed and the hammer strikes the string, the string resonates at a certain frequency, this is what generates that iconic piano sound as it is then transferred to the soundboard and rest of the instrument and projected out into the air.

Following our article on straight strung and overstrung pianos, today we wanted to take a quick deep dive into piano strings and piano wire, why they are so strong and how they impact the tone, feel and sound of your instrument.

What are piano strings made from?

Piano strings are almost always made from the same materials; high carbon steel, and copper. Both of these are incredibly long lasting, hard wearing materials that can keep up with the tension of the piano and most importantly, won’t snap easily, whilst still maintaining a fantastic ringing frequency when struck. In fact, high carbon steel is so strong and can be concealed so easily that it is also found in films and used as wire to hoist actors up!

The treble and middle of the piano uses three carbon steel strings per note, and the bass uses a carbon steel core with a copper winding. They are wound in the same way as a guitar string, in that they have a solid core, with an outer winding around the string, although on a piano, they are much longer, much thicker (especially in the lower end) and capable of a far higher tension.

The thickness of the plain piano wire varies from 0.2mm to about 1.5mm, with the thinner strings used for the higher pitched notes. This is because in order to create the signature bass range and general ‘fullness’ of an acoustic piano’s sound, the strings need to be thicker when the hammer strikes them to resonate at a lower and more powerful frequency. Around 50 different gauges (thicknesses) of string are available and found throughout the piano to ensure the tension of the strings are evenly distributed across the frame and soundboard

How strong is piano wire?


Piano wire is unbelievably strong. In fact, each string on a piano is tightened to between around 75kg and 100kg of tension, so one string on a piano has more tension than a whole guitar. All of this combined means the total tension of all the strings in a piano is around 20 tonnes, which is why a cast iron frame is needed.

Fun fact: That’s about the same weight as a fully loaded bus, or three African elephants!

Because of the required precision in tension and craft, in the bass end of the piano, the copper wound strings are hand wound in all instances. We use a local, Suffolk-based string maker, Barney Unwin, a master string crafter who is highly regarded as one of the best around.

What to do if a string on your piano breaks?

Despite being incredibly tough and hard wearing, piano strings do (very rarely) break. This is normally if the string has undergone a lot of sudden tension (for example not being tuned many for years) or has been kept in varying or damp temperatures as overtime the metal can become brittle.

The issue with piano strings is that unlike a guitar where a string can be casually replaced with a different string, piano strings are strung with a lot of precision to a very specific pitch. If a treble string on the breaks, the exact gauge must be matched and a replacement fitted, if a bass string breaks, the broken string has to be sent to our string maker, so an exact copy can be made. If it doesn’t match, the piano won’t hold the same sound it once did and often just sounds rather jarring!

The cost of replacement bass strings varies depending on the thickness and length of the string and the current price of copper.

Some piano wire makers produce a variety of different options from slightly different steels, some with a nickel coating, and each with their own unique tone and breaking load, which may suit unusual or antique instruments more than modern strings.

Think your piano is in need of restringing or tuning? Contact our piano tuning experts today!

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