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Wrought Iron - The History, Wrought Iron - The Myth, Wrought Iron - The
Truth
Wrought iron is a raw material although the expression Wrought Ironwork is
frequently used today to describe fancy ironwork which is in fact made from mild
steel.
Wrought iron was first produced around 1750 when Abraham Darby II (1711-1763)
solved the problem of making a suitable pig iron using a coke furnace. His
father Abraham Darby I (1677-1717) had developed the first coke furnace at
Coalbrookdale in 1709 but the molten metal produced was poured into sand moulds
to make cast-iron goods.
The process of making wrought iron was complex, time consuming and it required a
highly skilled workforce. Molten iron was cast into ingots (pigs) and stacked
one way then the other in a pile on the puddling hearth. Here it was heated and
"puddled" to remove impurities. The iron was then transferred to the
shingling hammer which was a gigantic power hammer which was capable of
earth-shattering blows which formed the iron into a billet. This was then
rolled, cut up into lengths, re-stacked and the whole process repeated over
again. The more times the process was repeated, the better the quality of the
finished wrought iron.
The rolling process was an art in itself requiring a minimum of four men with
massive long handled tongs which hung down on chains from the factory ceiling. A
pair of men stood at each side of a line of rotating rollers and had to catch
the red hot bar as it came through the rollers and guide it back through the
next set. As the bar was rolled progressively smaller it grew longer and became
increasingly difficult to control. The risk of injury was ever present.
The result of all their labours was a fantastic material which was a revolution
in its time. However, there were, and still are, disadvantages which are
inherent in wrought iron. It is not homogenous like mild steel but it is
laminated like plywood and has a tendency to de-laminate over time when moisture
penetrates between the laminations and forms rust which expands the material to
many time its original size causing damage to any adjacent materials.
 Here
the natural stone coping into which the wrought iron post has been fixed with
lead caulking, has been broken away and will have to be replaced. The lead
caulking which would originally have been flush with the stone coping, has been
squeezed out of the stone by pressure from the expansion of the rusting wrought
iron. The post itself is now very thin and will also have to be replaced due to
loss of material as the wrought iron has rusted away. This collateral damage
would not have occurred if the post had been made of mild steel or pure iron
which are homogenous and only rust on external exposed surfaces.
Although wrought iron has not been manufactured for nearly fifty years there is
a great deal of reclaimed wrought iron available. Dismantled bridges, railings
and discarded anchor chain
being common sources. This can be used where a client specifically requests
wrought iron perhaps for restoration or reproduction of an antique. However,
given the uncertainties of quality and provenance inherent in the acquisition of
any re-claimed or salvaged materials, and the potential disruption of the
laminations during the jointing and re-rolling of salvaged wrought iron, we would
always recommend the use of new pure iron, mild steel or stainless steel. All of
these new materials are certificated with known composition, reliability and
performance and meet fully with our modern world's ever-increasing demand for
accountability and traceability.
For more information about pure iron visit our sister web site: http://www.pureiron.com
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