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    INSPIRATION AND CHAT

CURRENCY AND METAL

Posted July 18th 2016

Historically, different precious metals have been used to make coins used for currency. Indeed, before there were standardised currency systems with coins, metals themselves were used on their own as a precious commodity representing value – typically those considered precious metals such as gold and silver. Historical records show that gold was used for accounting in Egypt during the third millennium BC, and silver in Mesopotamia.

Coins can be found in many ancient cultures with the earliest coins thought to be made from electrum, a naturally occurring alloy of gold and silver, and traced back as far as Ancient India circa. 6th century BC. In Western records, the earliest coins are probably those traced back to Lydia circa. 680 BC. They were made from electrum and fashioned in ovals.

The traditional coinage system in Britain is derived from the Medieval monetary reform of Charlemagne, much like the French monetary system. The reform fixed a ratio of 12 to 1 on the price of gold to silver, with the aim that basic coins of the same weight were equally suited as a currency standard – gold coins were much more valuable and rarely seen by most. Over the years the monetary system used has evolved and changed multiple times to get where it is today. The metals used have also changed, from gold, silver and copper, to bronze, brass and silver alloy.

Today coins are typically made from less precious metals – nickel plated steel and copper plated steel maybe, depending on the coin. The process of making them involves three distinct phases – making the blanks, making the dies and striking the coins. First, the metals to be used are melted and then extracted in a continuous strip, before being rolled out to the thickness intended for the coin. Out of this ‘sheet’, the blank coins are cut and then softened in an annealing furnace, as the process of rolling the metal out makes it very hard. Once cleaned, the blanks can be used. Next, a plaster model is made with the agreed design and then scanned by a probe to make a digital record. The design is then engraved on to a piece of steel at the size the coin will be and this is used to make the dies which will strike the coins. Finally, the blanks are put into a coining press where the dies will strike them, applying a pressure of about 60 tonnes, and they will be turned into coins.

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LEAD

Posted July 5th 2016

Lead is a chemical element belonging to the carbon group. Its symbol is Pb and it has an atomic number of 82. Lead is a post-transition metal in the periodic table and is characterised by a blue/white colour when freshly cut, that gradually tarnishes to a duller grey with air exposure. In its liquid form, the metal has a shiny, silver-chrome colour.

Characteristic properties of lead include high density, malleability, ductility and rather poor electrical conductivity in comparison to other metals. It is very resistant to corrosion and can be alloyed to other metals easily, resulting in a significant change in its properties. For example, small amounts of antimony or copper can be added to lead to increase hardness and improve resistance to corrosion by sulfuric acid.

There are many uses for lead including construction, batteries, bullets, and nuclear radiation shielding. In the construction industry lead is used in roofing, cladding, flashing and gutters, as well as in decorative moldings to fix lead sheets. It is also used to make glazing bars for stained glass windows, although this is a practice that has become less common than it once was.

Lead is a key component in lead-acid batteries, which are the oldest type of rechargeable batteries. Compared to newer technologies they are relatively inexpensive and still widely used with 40-45% of batteries sold worldwide representing lead-acid batteries. Their main uses are in automobiles, lighting and ignition, as well as backup power supplies for alarm and small computer systems.

Lead is highly poisonous and can be hazardous to human health if ingested, whether that is inhaled or swallowed. Long term exposure can affect the nervous system and can cause nephropathy, weakness in the fingers, wrists and ankles, increase in blood pressure and brain damage. During the 20th Century, the use of lead in paints was dramatically reduced due to fears of lead poisoning and by the mid-1980’s lead use was heavily curtailed in most things other than battery products. White lead paint is no longer sold in industrialised counties and old paint should never be stripped by sanding as the dust is very dangerous if inhaled. Lead poisoning has been documented as far back as ancient Rome, with some having attributed the dementia of many Roman emperors to its use as a sweetener in wine.

Lead is sold by William Rowland in the form of full ingots which can be cropped to customer requirements, as well as sheets, shots, powder and wire.

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