Rediscover Ornamental Ironwork

Rediscover Ornamental Ironwork

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By Chris Topp

Britain’s buildings are adorned with exquisite work thanks to expert foundries and talented smiths, such as Chris Topp, the art still thrives today.

Wrought iron takes its name from ‘worked’ iron – hammered into shape by a blacksmith. Tough and easy to forge-weld, it’s surprising so few architects use it today, especially given its superior corrosion resistance compared to its modern-day counterpart, steel. That so much ornamental work survives intact from 300 years ago says a lot more for the material.

Wrought iron has been used since medieval times. The traditional technique was to smelt porous iron ore over a charcoal fire, which allows carbon monoxide to reduce the ore to (still solid) pure iron that would be hammered into shape. Impurities would melt out during heating, but a small amount of carbon and other ‘slags’ – silicates, oxides and sulphides – remained, making the iron more fibrous, workable and less corrodible.

In William and Mary’s reign (1689-1702), immigrant wrought-iron workers from France and the Netherlands brought with them the Baroque style of decorative wrought ironwork. One of the finest was the French Huguernot Jean Tijou, who arrived c1689 and excelled at repousse work (see Glossary below). Examples of his artistry can be found at St. Paul’s Cathedral, Hampton Court Palace and Chatsworth. This was the beginning of wrought iron as high fashion. English craftsmen followed suit during the 1720’s and 1730’s, with the best examples from the likes of Robert Bakewell in Derby and brothers Robert and John Davies at Chirk Castle.

In 1709, at Coalbrookdale, the iron founder Abraham Darby pioneered the use of coke (much cheaper and more readily available than charcoal) for smelting iron. This made wrought and cast iron foundry pieces more affordable, setting in motion the rise of cheap ironwork that helped drive Britain’s industrial Revolution.

Toward the end of the 18th century, various techniques were explored to find more effective ways to produce wrought iron without charcoal. One of the most successful was the puddling furnace, devised in 1784 by Henry Cort. Molten ‘pig iron’ (brittle and high in carbon) was stirred to remove impurities. Wrought iron was prominent as an architectural art form into the industrial era, when it was steadily replaced by cast iron to make affordable mass-produced items, and then, from the 1850’s by mild steel.

Cast Iron
The Chinese were casting iron as early as 550BC, to make, for instance, weapons and figurines. In Britain, furnaces on The Weald used cast-iron moulds for domestic utensils, nails and cannon balls from roman times until the 1760’s. As the industrial Revolution progressed, cast iron was used mainly for structural purposes such as railway engines and bridges – in the late 1770’s Abraham Darby III built the Iron Bridge at Coalbrookdale.

It was only later, from the mid-19th century, that cast iron was more widely used to make railings, porches and balconies – offering a value-for-money alternative to wrought iron. At the great exhibition of 1851, Joseph Paxton’s Crystal Palace was made in new material, proving it could be used decoratively. Using moulds to cast identical designs, iron founders could now show customers pattern books, instead of using a master blacksmith to produce a unique piece.

Mild Steel
Another form of refined iron is mild steel. From the mid-19th century, steel rose to replace wrought iron, following Henry Bessemer’s invention of the Bessemer Converter in 1856. This produced steel by blowing air through cheap, molten pig iron, removing impurities at high temperatures by oxidation and led to the mass production of steel. More expensive wrought iron and the skills associated with it gradually disappeared until the last ironworks ceased production in the UK in 1974.

Today, Chris Topp Wrought Iron Works is possibly the only specialist wrought-iron manufactory still making puddle iron in bars or sheet form, then working it into pieces, mainly for restoration purposes.

What to look for in ironwork:

Wrought-iron railings. These were handmade – based on surviving fragment – by Chris Topp for a 17thCentury house in Ripon, North Yorkshire. Look for details such as simple delicate railing heads, tapered or flattened bar ends worked into snub ends or scrolls and riveted or forged joints.

Cast-iron railings at Whitwell Refectory, Derbyshire, made by Chris. Cast iron is often mass produced but can be complex shapes. Components tend to be thicker than the wrought iron. Railing heads are often chunky; sections linked by screws or nuts and bolts and lugs. Look for seams that run down the sides of cast items at the join between moulds. Mouldings are mitred and fastened using panel pins.

Mild steel railings (below, bottom) are often not as elaborate as historic wrought iron – unless made by an expert to mimic it, as these, in an art nouveau design, by Chris. Sections are slimmer than traditional wrought iron.

Techniques still used today

Expert Chris Topp explains some of the processes used to create pieces:

Chain straightening: ‘To make new pieces of wrought iron, we use scrap wrought iron in the form of heavy admiralty chain (links weigh about 100lb each). One link will be warmed and straightened to form an iron bar using a hammer and rolling mill.’

Traditional forging: ‘To shape a bar, we heat it and hammer it, stretch it, or punch holes in it. We use a hammer and anvil and wear a leather apron – exactly the same as Roman and Viking blacksmiths. Making railings, balconies or gates involves working the components into shape at the right size. We draw a template onto tin to check the pieces are the right size. Then we forge-weld the components using extreme temperatures – the joining edges become incandesant (dripping white hot). We don’t wear gloves unless a piece is very short when we’ll use tongs. An experienced smith will always feel a length of iron with the back of his hand before picking it up.’

Piling iron to make sheet iron: ‘We make a tower of shorter iron pieces which we will heat in a muffle furnace – a chamber generating temperatures up to 1,500°C. The pieces become white hot and stick together – a process we help along by ‘smiting’ the lumps with a hammer to knock them together. The metal is then rolled out into a sheet with a rolling mill.

Caring for wrought iron

• Consult an expert blacksmith for initial repair or restoration.

• Strip off old layers of paint by mechanical or chemical means (grit blasting removes the iron’s own protective layer of oxide).

• Look for signs of water lodging in and rust seeping from joints. Any chipping of well ventilated areas is not too significant.

• Attend to problems as soon as possible in warm dry weather so joints can dry out. Remove rust scale by local heating.

• Apply an oil-based rust inhibitor to joints then reseal damaged areas with paint.

• Repaint periodically, but at most five yearly.

Glossary

Blast Furnace – Used for smelting metals. Fuels and ore are supplied through the top of the furnace; air/oxygen is blown into the bottom of the chamber. End product is molten metal, slag and gas.

Bessemer Convertor – Process for converting pig iron into steel. Impurities are removed by oxidation at high temperature.

Cast Iron – Strong but brittle form of iron with low melting point. Made by re-melting pig iron to remove impurities, then ladling molten iron onto moulds to make castings.

Charcoal Wrought Iron – Early form made by reducing iron ore over a traditional charcoal/wood fire.

Puddling – Process of making wrought iron using reverbatory furnace and stirring rods to oxidise pig iron and remove impurities.

Puddled Iron – 19th Century form of wrought iron.

Repousse – Technique of pressing and hammering sheet of metal to raise it into a 3-D object, such as armour.

Slag – By product of smelting metal ores.

Wrought Iron – Tough and malleable. Has filaments of slag in the metal. Resists rust.

This article appeared in Period Living magazine – September 2007

Chris Topp & Co Ltd is a 30 year old company, based in North Yorkshire which is the only producer in the world today of genuine wrought iron and a leader in the restoration of heritage ironwork. They are one of the best known names for the design and creative production of modern and traditional iron work.

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