Occasionally a wire will be broken and need to be replaced. If the string is not replaced promptly, it can cause uneven wear on the hammer that will lead to additional repairs being necessary. A string can break for a number of reasons. In most cases of string breakage, there usually is the presence of rust that weakens the string. The string might break because of a kink or a bend in the wire, or there may be a defect in the wire. In tropical areas or areas with high humidity, pianos are made using tinned wire to prevent excess rust. Strings frequently become brittle with age, and the splintered ends of a broken wire can testify to that. Concert instruments and other pianos that receive a lot of heavy use are notorious for popping strings.
When a piano is being tuned and a string breaks, it is usually due to a weakness in the string as listed above. Sometimes the wire can also be broken by a piano tuner who does not use a proper technique in using the tuning lever. When the broken wire is examined and the wire shows evidence of "necking down" (the wire being overstretched to the point that the wire is damaged) it often is the fault of the tuner. If a piano is flat in pitch because it has been neglected, the pitch raise can cause rusty strings to break. However, I have successfully raised pitch on a number of old pianos that had very rusty strings and were more than a whole note flat in pitch, and often the entire tuning will proceed without any of the strings breaking. Other times I may be tuning a much newer piano that is not flat, and a string will just decide to break.
When a piano is being tuned and a string breaks, it is usually due to a weakness in the string as listed above. Sometimes the wire can also be broken by a piano tuner who does not use a proper technique in using the tuning lever. When the broken wire is examined and the wire shows evidence of "necking down" (the wire being overstretched to the point that the wire is damaged) it often is the fault of the tuner. If a piano is flat in pitch because it has been neglected, the pitch raise can cause rusty strings to break. However, I have successfully raised pitch on a number of old pianos that had very rusty strings and were more than a whole note flat in pitch, and often the entire tuning will proceed without any of the strings breaking. Other times I may be tuning a much newer piano that is not flat, and a string will just decide to break.
