Bell metal metal used is a high-tin alloy of copper and tin with approximately a 4:1 ratio of copper to tin (78% copper, 22% tin). This is a much higher tin component than that used in statuary bronze. A range of percentages of tin content can vary from 20 to 26%, depending on the founder who has arrived empirically at their own alloy ratio. It has been found that increasing the tin content increases the decay time of the bell strike, thus making the bell more sonorous. Taking into consideration overall properties, such as tensile strength, hardness, wear resistance, cast quality, sound,
Antimicrobial copper-alloy touch surfaces University Hospital in Manhasset, New York. An alloy of 90% Cu 10% Ni significantly lowered the microbial burden, primarily "Staphylococci", on arm surfaces of phlebotomy chairs versus wooden arm surfaces. The median reduction for total bacteria on the copper alloy chairs arms was 90%. Use of the chair with copper arm tops resulted in a 17-fold lower risk of exposure to environmental microbes than when patients used the standard chair. The majority of the samples from the chairs with copper components were below the 500 CFU/cm level believed to represent a risk to hospital patients. The microbiocidal properties of the