All metal bells can be damaged by age and abuse. Most common are the chips & dings at the lip that come with trauma to the lip. Cracks occur if the metal is too hard, cooled iregularly, with casting imperfections, struck with too much force, and as a result of metal fatigue with aging and repeated use. Very cold weather can result in temporary hardening that can increase the brittleness of the bell. Repeated freezing and warming can accelerate the metal fatigue that occurs naturally with age. Very large bells such as the Czar Kolokol in Moscow have excessive weight at the rim relative to the body and the shear weight can cause loss of a large piece of the rim, which happened to the Czar Kolokol.
Harry Long, MD