Before the advent of steel, copper, bronze and brass were the workhorse metals of the day. With recorded use for more than 10,000 years, they have long been valued for their malleability and corrosion resistance. Some of the earliest tools, weapons and jewelry incorporated the use of these metals. Many early civilizations owe their prosperity to the discovery and ability to smelt, alloy, fabricate and trade copper.
Copper is a very malleable metal element prized for its high electrical and thermal conductivity. Today it is used primarily in electrical wires, roofing, plumbing, industrial machinery and ballistic tips for the military and firearms industries alike. Machining of copper is possible, but producing intricate, smooth parts is difficult. Many of the isotropic finishing methods, vibratory deburring, tumble polishing and centrifugal barrel finishing for example, allow for more complete copper polishing without the need to alloy it with other metals.
Most copper is mined from open pits by crushing the ore rich rock into smaller bits, pulverizing them into a powder and sending it through a chemical leaching process that finally extracts the pure copper. Chile currently produces roughly a third of all copper in the world, followed by the United States, Indonesia and Peru. Half of all the copper mined in the world is used to manufacture electrical wire and cable conductors.
Brass is an alloy of copper, zinc and other trace elements and is prized for its gold-like sheen. By adjusting the proportions of trace elements certain strength and surface finishing characteristics can be achieved. Brass has a very low friction coefficient making it ideal for locks, bearings, shell casings, valves, musical instruments, plumbing fixtures and electrical components. Many OEM’s, aerospace and automotive manufacturers use vibratory deburring and centrifugal polishing to make their parts into finished products.
Bronze is another alloy of copper and contains about 12% tin. Historically it was used for tools, weapons and other pre-steel applications requiring a metal with strength greater than that of brass. Today, bronze is used for bushings, bearings, springs, gears and other high stress and wear applications. Bronze is ideal for many of the deburring and polishing options available by mass finishing. From guitar and piano strings to poured bronze castings, musicians and sculptors alike are familiar with the benefits bronze offers.
ISO Copper Polishing experience has made us the natural choice for firearms manufacturers, precision machining houses and OEM’s alike. By selecting the appropriate tumbling media for each specific copper alloy and combining it with our isotropic copper finishing expertise, we’re able to create the best surface finishing techniques for each specific application. Take a look at some of our previous projects or send us a sample and we’ll process it for free so you can see first-hand why machine shops to Fortune 500 corporations choose ISO Finishing as their partner for copper polishing.