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Greetings Vern,
In the Iron & Steel Preservation Newsletter of June 2015, I wrote about wrought iron and my experience with it while working for the Calhoun County Historic Bridge Park restoring nineteenth and early twentieth century riveted truss bridges. To this day I continue to learn about wrought iron. A.M. Byers Company's handbook (1939), Wrought Iron: Its Manufacture, Characteristics and Applications (by Byers metallurgists Aston & Story), has led me to books and publications that have convinced me that if wrought iron had continued to be produced and refined it would have important applications in today’s infrastructure and building architecture. It is surprising that a metal widely used for centuries was so soon forgotten by many in the engineering and industrial fields. Although wrought iron is no longer found in recent construction, structures containing wrought iron are still in use today, and knowledge of the characteristics of this metal is valuable for its maintenance and preservation.
Vern Mesler 2023
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Wrought, Iron. The image most people have when they hear those two words together is of a fence at the entrance of an old cemetery, or maybe patio furniture fabricated from steel round-stock with simple bent scrolls made in China (and on sale). We are surrounded by metal, and for most people there is no difference between an old cast iron fence surrounding a cemetery or the polished metal on a new vehicle. Look around the home, business, or the local coffee shop, and it is steel in many forms and shapes one will encounter, not wrought iron. Wrought iron was last commercially available over fifty years ago, and for those who work with metals the knowledge of wrought iron has receded further into historic materials records. Today, many in the metal professions confuse cast iron with wrought iron and wrought iron with steel. These three are very different metals. One of the last mills to produce wrought iron was A.M. Byers Company, in Pittsburgh, Pennsylvania, established in 1864 and closed in 1969. | |
"Wrought iron is best described as a two-component metal consisting of high purity iron and iron silicate, a particular type of glass-like slag. The iron and the slag are in physical association, as contrasted to the constituent of other metals. Wrought iron is the only ferrous metal that contains siliceous slag." (Aston & Story) | |
Beginning in the early eighteenth century, wrought iron was produced in a hand-puddling furnace, and the worker who manned the furnace was called a puddler. "The quality of the wrought iron produced in the hand-puddling furnace was directly proportional to the skill of the puddler and beyond that skill no scientific control was possible." (Aston & Story). It took exceptional observational skill and physical ability of the iron puddler to produce (with his helper) 800 pounds of quality wrought iron in less than two hours. Byers began developing their mechanical puddling process in 1915 to replace the iron puddler, and in 1930 Byers opened a new industrial plant in Ambridge, Pennsylvania, to manufacture wrought iron, increasing output to 6,000 pounds of quality wrought iron in less than two hours. | |
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An open-air museum operated by the Ironbridge Gorge Museum Trust was built on the former industrial complex located in the Madeley area of Telford, England. On our 2019 historic bridge tour* in England and Wales, I had an opportunity to inspect a wrought iron puddling furnace at the Ironbridge Gorge Museum. I was surprised at its interior construction and realized the furnace could be replicated. A local blacksmith artist, Vincent Thompson, accompanied us through the museum’s industrial machinery (after which we enjoyed a traditional fish and chips lunch with his family). Thompson is a skilled craftsman artist whose Facebook site is testimony to his skills. We hope to return to the Ironbridge Gorge Museum for a detailed inspection and documentation of the museum's puddling furnace.
*Nan Jackson planned and organized a detailed three-week tour of some of UK’s historic bridges, museums, and industrial sites. We have much more to see and hope to plan another bridge tour.
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A puddling furnace can accommodate about 500 pounds of pig iron. The furnace is charged by hand, the “pigs” lifted through the charging door. | |
Vincent Thompson and Vern Mesler at Blists Hill Victorian Town, Ironbridge. Vincent and Vern re-enact charging the furnace. | |
G. R. Morton Ironworks puddling furnace displayed at Blists Hill Victorian Town, Ironbridge. | |
In this historic photo, the puddler pries up the pig iron from the bottom of the furnace with an iron bar. He keeps it exposed to the oxidizing flame until all the iron is melted. “The mixture of slag and iron becomes thick and pasty and the iron is said to have ‘come to nature’” (H. M. Boylston 1936). The bloom, while still retaining its heat, is moved by hand tongs to rollers and rolled into bar form (known as “muckbars”). | |
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Wrought iron in the early twentieth century was still considered to have a future because of its unique qualities.
"During the past decade there has been a rapidly growing demand for wrought iron in many different products. This demand has been accompanied by a need for information on the qualities of the material and their application to present day problems." (From the preface to the second edition of the A.M. Byers Company's handbook, Wrought Iron: Its Manufacture, Characteristics and Applications, 1939.)
At the Twenty-Seventh General Meeting of the American Iron and Institute (1925), James Aston (metallurgist for the A.M. Byers Company) promoted two properties of their wrought iron products that they considered to be superior to steel: “Superior ability to withstand the fatigue of shock and vibration, and the ravages of corrosion.”
Through published books, advertisements in trade journals, and company technical bulletins, A.M. Byers supplied technical assistance in applications where these outstanding characteristics were used.
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Dr. David B. Steinman, design engineer for Michigan’s Mackinac Bridge, took advantage of one of these features of wrought iron for the protection of the bridge’s concrete substructure against wet-dry corrosion and abrasion by winter ice in the straits of Mackinac, specifying over 270 tons of wrought iron plate for this application, delivered by Byers.
The Mackinac Bridge opened to traffic in 1957 and remains a vital transportation link today.
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Wrought Iron in Bridge Construction | |
Wrought iron was still being used in the fabrication of bridges in the early and mid twentieth century and was recognized by bridge engineers for its corrosion resistant qualities. Iron, slag, and the fibrous nature of wrought iron arrested and resisted corrosion. An article in Railway Age (March 3, 1934) details the installation of wrought iron plates on a bridge deck for a Missouri Pacific underpass at Little Rock, Arkansas, one of many examples detailed in Byers’ book, Wrought Iron in Bridge Construction. Railroad bridge engineers maintaining railroad structures provided Byers with engineering documentation for many of the articles in Byers’ book on bridge construction. | |
Byers Genuine Wrought Iron Pipe | |
Whether it is wrought iron plate in a bridge deck or in a boiler on a steam ship or miles of wrought iron pipe for steam heating and plumbing systems in large buildings, the corrosion resistance and fatigue characteristics of wrought iron have been attributed to what Byers calls “The Vital Element,” namely iron silicate, a “time-defying factor in Byers Genuine Wrought-Iron Pipe” distributed by their rolling process uniformly as fibers throughout the material (1930 Time Magazine article “Old Man River”). Byers promotes their wrought iron products as resistant to corrosion and able to withstand shock and constant vibrations. Their publication, Byers Pipe (1922), highlights the use of wrought iron in buildings such as the Cleveland Arcade, erected in 1889 in Cleveland, Ohio, that used 60,000 feet of Byers pipe. | |
Wrought Iron into the Future | |
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Preparing for this newsletter, I’ve acquired books, publications, and online printed materials about the production of wrought iron. It is the A.M. Byers Company, this country’s oldest and largest producer of wrought iron, that I found to be of greatest interest. I plan to continue to research and document Byers’ wrought iron manufacturing process, both the manual puddling and the mechanical puddling processes, with a future objective of building a working wrought iron manual puddling furnace (based on the design at Ironbridge) for educational use in promoting knowledge and understanding of the process and the material. I am scheduling a WebEx meeting (February 3, 2024, 4-5pm EST) to invite people interested in the history and production of wrought iron to explore the feasibility of such a project. Email me if you are interested in attending the meeting.
Vern Mesler
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Click on the image to view a video about the Calhoun County Historic Bridge Park, produced by Central Michigan University for Destination Michigan, a program aired through PBS. | |
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Iron & Steel Preservation Program Fund
Lansing Community College Foundation
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Please consider contributing to the Iron and Steel Preservation Program Fund. This fund was established to support projects, research, conferences and scholarships related to the repair, rehabilitation, and restoration of metals. The Lansing Community College Foundation is a nonprofit 501(c)(3) corporation. Use the link below, and specify "Iron and Steel Preservation Program Fund" as the designation in the online form. Thank you for your support!
Iron and Steel Preservation Program Fund
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