How Gold Chains Are Made
Some of the first gold chains date back to the ancient cultures of Iraq and Greece. They were symbols of wealth, royalty and the divine. Luckily for us jewellers now make these personal treasures more affordable and more durable than ever.
In this factory all that glitters is gold. Pure gold is fairly soft and bright yellow so it's common to create an alloy to strengthen it and alter its colour. Copper lends a reddish hue and brass helps the alloy melt more quickly than gold and copper would alone. Depending on the ratio, adding the metals produces 14 or 18 karat gold.
The mix is melted in a crucible at more than 1000 degrees Celsius. Just three of these scoops are enough to make about 5000 14 karat gold chains. The molten alloy is poured into a casting machine, water cools the metal to around 370 degrees Celsius solidifying it. The metal passes through a round die which shapes it into a golden rod that's nearly 2 metres long.
After the rod is cut in half it's passed through what's known as a breakdown mill. The machine reshapes the rod from circular to square so it will be easier to stretch. The next stop is called a tandem mill, it has twelve rollers that stretch the rod until it's as thin a piece of spaghetti. As it emerges, rollers shape the rod into a coil that's 24 metres long.
The coiled metal is softened in an oven. Then, what is now a wire is uncoiled and continues to stretch as it's passed through a die lined with industrial diamonds. To prevent overheating, the machine sprays lubricant to cool the wire while reducing it to the width of a human hair, it's final size.
The wire then winds into a spool almost 3 kilometres long. Next, 32 of the spools are unwound and the wires are run through another oven which softens them further. Just in case you think that working here is a golden opportunity, you should know that security is very tight. Employees must pass through metal detectors before going home and wearing jewellery to work is strictly forbidden.
This machine makes what's called cable chain, it passes wire through a link and closes it to make another link. The machine makes 600 links per minute. Here a random quality check is being carried out.
This machine makes a venetian style chain. The wire passes through a channel where mechanical jaws bend it over a die to make a link with the proceeding segment. To make what's called a spider style, this machine passes a wire through up to 5 loops before closing the link.
For a Figaro style chain, this machine makes 3 short links before a mechanical arm moves the chain to another area to add one longer link. The arm then moves it back to add three more short links.
The simplest style is known as a rogue chain. To make it this machine threads a wire through then closes it to make another loop.
The finished chains are coated with a lubricating powder than prevents the links from sticking to each other during the next step when the chains are heated to 815 degrees Celsius. This activates a soldering agent which was added to the metals earlier. It fuses the ends of the links to each other.
This machine welds a link to a clasp on the chain. A tag indicating the gold quality goes onto the clasp. Finally the chains go through 4 chemical baths which clean them thoroughly then they're plated with a layer of 14 or 18 karat gold which creates a more vibrant finish.
After one last quality check these chains are ready to dazzle their way to a neckline near you.
The Perth Mint deals in precious metals, providing services and products all around the world.