Copper Flat Bar Class I (C11000) Copper Flat Bar is commerically pure copper and is most commonly used for welding fixtures, anodes, bus bar in electrical power installations, ground straps, commutators, etc. It is easily bent, soldered, drilled, riveted and formed to fit almost any design specification. Class II (C18200) Copper Flat Bar combines high electrical conductivity with high strength. Typical uses include welding electrodes, current carrying arms and shafts, circuit breaker parts, and all parts requiring higher strength than commerically pure copper yet requiring high electrical conductivity. Class III (C17510) Copper Flat Bar has high thermal conductivity combined with good hardness, wear resistance and high temperature strength. Machines better than C110 alloy.