HISTORIC IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.

Chapter 4.

4.1 Historic Availability, Characteristics and Use of Wrought Iron. 1/2.

Some scholars believe that the quality of wrought iron and the skill of the ironsmith reached its zenith early on and then steadily declined until its demise after the industrial revolution demanded more materials and faster processes that led to mass production and mechanisation.

In the book An Encylopaedia of Ironwork, Otto Hoever gives a precise description of the rise and fall of 'hand wrought ironwork from the middle ages to the end of the 18th century' when he believes it fell into unrelieved decline.

However he describes only the rich, ornamental work beloved of the church, wealthy merchants and kings, whose expectations were of the highest. In the 12th century, abbey and cathedral doors were being screened with superbly wrought and highly detailed charcoal iron gates with leaf and scrollwork of outstanding delicacy.

This tradition of excellence continued in the great European countries of Germany, France and Spain with the peak of craftsmanship appearing in France in the C13th. In England, it seems while the craftsmanship was not poor it was nothing but a shadow of its European counterparts. The quality declined according to the fashions of the times, from Gothic to Renaissance to Baroque to the final more simplistic nature of Classicism.

In one telling phrase he gives us an insight into the stock of iron available and its period of popularity;

'We may say that the use of one of the three main classes of bars; flat, round and square is a characteristic feature of a particular style. Thus Early Gothic favoured either narrow or broad iron bands, and Late Gothic, in the north, the round bar. In the south, above all in Italy, the Renaissance introduces the square bar which was also preferred by Rococo smiths, particularly by the French.' (Hoever.O, 1954).

In England there certainly was no shortage, and wrought iron and even steel for edging tools and making weapons was being imported early on. Iron was bought by the hundredweight (cwt) from Spain as early as 1266 and in 1275 cost 3s.1d/ cwt when brought to Canterbury. Iron from Pont-Audemer in Normandy was being bought in Norwich in 1285 for 15s.6d/ cwt. In 1316 they were buying Swedish Osemund, an iron almost like steel, by the sheaf. (Salzman LF. 1952 p286).

Iron production was localised and in particular flourished in the Weald. Although only one iron-making site is recorded in the Domesday Book of 1086 from the 12th Century there is evidence of a growing industry in the region, supplying markets in the south of England.

In 1496 the first documented blast furnace was established in England in Ashdown Forest in Sussex. Within fifty years the primitive bloomery furnaces, which had been used since the Iron Age, had been superseded by the technology of the blast furnace and Walloon finery already established on the continent.

Making use of water power led to a massive expansion of the industry during the second half of the 16th Century and resulted in over a hundred blast furnaces and associated finery forges being established in the Weald. (Wealdon Iron Research Group, 2002).

In 1724, Neve described the types of iron readily available in England.

(1.) English, which is a coarse sort of Iron, hard and brittle, fit for Fire bars, and other such coarse Uses.
(2.) Swedish, which is of all sorts the best we use in England. It is a fine tough sort of Iron, will best endure the Hammer, and is softest to file, and therefore most coveted by workmen to work upon.
(3.) Spanish, this would be good as Swedish Iron, were it not subject to Read sear, (as the Workmen phrase it,) that it is to crack betwixt hot and cold. Therefore when it falls under your Hands, you must tend it more carefully at the Forge. But tho' it be a good, tough, soft Iron, yet, for many uses Workmen refuse it, because 'tis so ill and unevenly wrought in the bars, that it costs them a great deal of labour to smooth it; but it is good for all great Works that require Welding; as the Bodies of Anvils, Sledges, large Bell-clappers, large Pestles for Mortars, and all thick strong Bars, &c. But 'tis particularly chosen by Anchor-smiths, because it abides the heat better than other Iron and when 'tis well wrought, is toughest.
(4.) There is some iron that comes from Holland, (tho' in no great Quantity,) but is made in Germany. This sort of Iron is call'd Dort-squares, (only because it comes to us from thence, and is wrought into Bars of ¾ of an Inch square) 'Tis a bad coarse Iron, and only fit for coarse Uses, as Window-bars, Brewers-bars, Fire-bars, &c.
(5.) There is another sort of Iron us'd for making of Wire, which of all sorts is the softest and toughest : But this sort is not peculiar to any Country, but is indifferently made where any Iron is made, tho' of the worst sort; for 'tis the first Iron that runs from the Minestone when 'tis melting, and is only preserved for the making of Wire. (Neve, 1726 p179). Appendix 3.


Experimentation in developing new methods of production was now widely reported. A Weekly Essay in April 1731 from The Gentleman's Magazine (Vol 1 1731 P166) outlines the efforts of a Mr Fallowfield in trying to use peat as a fuel and his feud with a Mr Wood who was trying to use 'Pulveris'd Ore' burnt with pit coal. Mr Wood, was in turn berated by a Mr Tomkyn for the poor quality of the iron and its difficulty in working. Mr Tomkyn significantly suggests the use of 'Pit Coal coak'd' and this is the direction mass production took.

Rising demand for iron, fuelled in part by increased mechanisation and therefore factory machinery was met by the 'Ironmasters'. In particular the dynasty of Abraham Darby who developed coke fired furnaces. At first only suitable for casting iron they were later refined to produce iron suitable for hammering into wrought iron. This laborious process which required 12 hours of water-powered hammering per ton was revolutionised by Henry Cort's puddle furnace of 1783-4 which by stirring the molten iron before rolling it in a mill could produce the same amount in only 45 minutes.

By 1775 'Iron-mad' John Wilkinson was using Watt's steam engine (which he had manufactured) to work the bellows of his furnaces (so that the location of the foundries was moved from the rivers to the coalfields) and output increased. Wilkinson supplied the components of the first iron bridge in 1779, built the first iron ship, the first iron lavatory and the first iron coffin - in which he was buried.

'Between 1800 and 1830 the iron industry suffered gigantic convulsions in output with the change from war to peace in 1815 and the first stirrings of railway building in the 1820s, coupled with a legacy of over-capacity from the period of rapid expansion between 1790 and 1810. Forge technique improved during these years and wrought iron regained its traditional position as the main end product of the industry, establishing itself as a major export good for the first time.' (Riven. P. 2002)

In the 1830's and 1840's iron production underwent another revolution, because of technological innovations like the 'hot blast' iron furnace and because of the advent of a major new customer, the locomotive railway which saw its commercial beginnings at the Rainhill Trials of 1829.

In the 1850's considerable scientific strides were taken in materials science and empirical values were demonstrated for the strength of wrought iron. Using Bramah's hydraulic press, wrought iron ties were tested to destruction in an experiment at Her Majesty's Dockyard Woolwich (The Builder, Vol X Mar. 1852 p199). This knowledge revolutionised the use of constructional iron as it was realised that the sectional strength could now be accurately calculated. This of course meant that the sections became more slender in the pursuance of economy.

Availability of puddled wrought iron reached its peak in the first half of the C19th. In 1856 mild steel, an alloy of iron and carbon was discovered during Henry Bessemmer's attempts to mass produce wrought iron and this new, inexpensive and easily machined material quickly superseded wrought iron for most uses.

However, it was not fashion or mild steel that killed off smithcraft but cast iron. Cheaper to produce, requiring unskilled labour except for the sculptor and founder, cast iron products could be produced en masse and all identical.

4.2 Observations

 

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