What is the “tin” in Tinopolis? The science behind Llanelli’s history…
BY Rhodri Owen
02 April 2026
Nicknames for towns and cities have existed as long as the towns and settlements themselves, often reflecting its significance in its time. Llanelli has been known as Tinopolis for around 200 years and reflects its contribution to the tinplate industry during the 1700s, 1800s and 1900s, supplying markets across the world – the town’s name in this example “does exactly what it says on the tin” to quote a famed Ronseal advert.
The town’s rise as an industrial powerhouse was driven by several advantages. Its location on the South Wales coast provided easy access to imported raw materials and export routes via nearby docks. In addition, the abundance of coal in the region fuelled the furnaces needed for smelting and metalworking. By the late 1800s, Llanelli was home to dozens of tinplate works, employing thousands of workers and dominating the local economy.
At its peak in the 1880s, Llanelli produced 90% of the world’s tinplate, exporting to countries such as the United States and Argentina. Although the tinplate industry declined in the 20th century due to technological changes and overseas competition, its legacy remains a defining part of Llanelli’s history, with Trostre Works still producing approximately 400,000 tonnes per year of tin, chrome and ‘polymer’ coated steels. The nickname “Tinopolis” continues to symbolize the town’s proud industrial heritage and its once vital contribution to global manufacturing.
But why tin? What’s so special about it?
The tinplating of steel is widely used because it combines the strength and low cost of steel with the corrosion resistance and non-toxicity of tin. The most common application synonymous application these days is in the production of food and drink – however many items use tinned steel to store products from paint to oils and even toys. Tin is highly resistant to corrosion and does not readily react with water or oxygen, making it an ideal protective coating. Additionally, tin is non-toxic and does not impart taste or odour to food, which is critical for food packaging.
The main reason for tinplating is to protect the underlying metal from oxidation and rust. In nature iron and steel are prone to corrosion when exposed to moisture and oxygen which can significantly reduce their durability. Tin, on the other hand, is much more resistant to corrosion and forms a protective barrier that prevents environmental elements from reaching the base metal. This makes tinplated steel ideal for applications such as food cans, where both strength and resistance to contamination are essential.
Where does tin come from?
Tin is a soft, silvery-white metal that formed deep within the Earth through geological processes that predate life itself. Tin, like many elements, was created in the heart of stars. During the life cycles of massive stars lighter elements fuse into heavier ones under intense heat and pressure. When these stars explode as supernovae, they scatter their atoms across space. Over time, these atoms become part of new star systems and planets.
The tin found on Earth today was incorporated into the planet during its formation around 4.5 billion years ago. That’s hard to appreciate, but a good way to think about it is if that was January the 1st in any given year, dinosaurs would appear on December the 15th and the first humans will arrive on December the 31st at 11:58 pm. It’s a long time ago.
The earliest known use of tin dates back to around 3000 BCE, during the Bronze Age. Tin’s significance lies in its ability to alloy (mixture of two or more chemicals to enhance its properties) with copper to produce bronze, a metal that is harder and more durable than either metal alone. This discovery marked a major technological advancement, enabling the production of stronger tools, weapons, and artefacts. Once again humanity advances through finding the easiest means to kill each other.
The rise of civilizations in regions such as Mesopotamia, Egypt, and the Indus Valley relied heavily on bronze to give them an advantage, an advantage which is tied to tin production. However, tin deposits are geographically limited, one of the most famous historical sources in the UK was Kernow (Cornwall), where rich tin deposits were mined extensively. Evidence suggests that tin from Kernow was traded across Europe and the Mediterranean, reaching as far as ancient Greece and Rome.
It is the Romans we can thank for the naming of “tin” as a chemical element. We know it as an Anglo-Saxon name from Germanic tin-om but its Roman or Latin word is Stannum and is recorded as Sn on the periodic table due to that origin. Who gave the Latin name, or even the Germanic is lost to history.
The science!
In nature, tin is found in the mineral Cassiterite (tin oxide) and there has historically been plenty in Kernow. This mineral on its atomic level is two parts oxygen to one part tin, in solid form. To add to copper to make bronze, or even to line iron in tinplating, tin is placed in a furnace to get rid of the oxygen through a chemical reaction we may more commonly know as smelting.
The smelting takes the ore, Cassiterite, mixed with coal or coke and limestone and is heated. So what happens?
In chemistry the formula used is:
SnO2 + 2CO → Sn + 2CO2
What does this mean? Cassiterite (SnO2 – tin and two oxygens) needs the oxygen to be taken away. How?
The carbon from coal (or coke which is a purer form of carbon from coal) reacts with the oxygen from the air to create carbon monoxide (that really bad gas we can’t smell or taste so we need monitors in our homes if we have gas fires or boiler). Carbon monoxide has one carbon atom and one oxygen atom (hence mono- - ancient Greek for single).
Cassiterite (tin and two oxygens) is “weak” at its atomic level and the oxygen atoms are looking to partner up and leave the tin under the right circumstances. Carbon monoxide is that right partner as its structure means it ‘looks’ for oxygen, attracts it even, and in the reaction takes away the oxygen found in the Cassiterite. As oxygen is removed from Cassiterite it leaves metallic tin in a purer form. This oxygen combines with carbon monoxide (for those paying attention, the singular form) and is released as carbon dioxide (CO2 - … yes you got it, two parts of oxygen).
But that is not the only bits in ore, so limestone is used as a flux (a purifying ingredient) to take away other minerals or ‘impurities’, floating on the heavier purer tin, leaving tin to be tapped off (a small hole to let it out from the bottom of the furnace) for use in say bronze making or 5 thousand years later industrialised tinplating.
Our bronze age forefathers may not have known the chemistry, but somehow they certainly knew how to make it!
How was it industrialised?
Kidwelly Tin Works was the first industrialised tinplating works in the County in 1737; while in the Llanelli area, Dafen Tinplate Works started production in 1846/48.
These works, as well as others later, were started, funded or supplied by notable families with names now familiar to us that include the Vaughans, Nevills and Stepneys. That would be an article in its own right.
Hot-dip tinning is the older of the two techniques used in the tinning process and involves immersing the cleaned metal into a bath of molten tin. As the metal is withdrawn, a thin layer of tin solidifies on its surface. While this method is relatively simple and effective, it can produce coatings of uneven thickness and is less commonly used in modern large-scale production.
A more uniform coating was developed by electrolysis, which means using an electric current to form an even coating on the iron, ensuring its reliability and consistency.
The process of preserving food in a sealed container was invented by Frenchman Nicolas Appert in 1809 using glass jars, followed by fellow Frenchman Philippe de Girard who patented the use of tinning iron in 1810. But, as Britain and France were at war between 1803 and 1815 (which also funded the furnaces at Furnace that produced cannon balls), Peter Durand had the patent from king George III in 1810.
Early uses of tinplate was produced to manufacture kitchenware and utensils as well as other household items. Some local manufacturers took advantage of these new materials later such as Felinfoel Brewery Company, which became the first brewery in Europe to produce beer in cans in 1935 made possible by locally produced tinplate. The tin coating not only prevents corrosion but also provides a non-toxic, non-reactive surface that helps preserve the contents.
From an environmental perspective, tin production and tinplating present can present an opportunity and be destructive, such as coal extraction locally. Mining and smelting can generate waste and emissions, including tailings and gases such as sulfur dioxide. However, tin is highly recyclable, and recycling processes require significantly less energy than primary production. Tinplate, for example, can be easily recycled by melting and reusing the metal.
Tin and its applications have played a remarkable role in shaping both human history and modern industry, from the ancient development of bronze to the global tinplate trade that defined Llanelli. Tin’s journey from the heart of stars to everyday products highlights its enduring importance and the lasting influence it continues to have on technology, industry, and society.
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‘What happened to the wealth generated if we had 90% of the global market in the late 1880s?’
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