The Tippecanoe Battlefield Fence Restoration: A Case Study
May 5, 2009
A cold rain fell throughout the night and into the early morning of Nov. 7, 1811. Along the banks of Burnet’s creek in the Indian Territory – later to be known as Indiana – 1,000 U.S. troops camped on little more than 100 acres of high ground near where the Tippecanoe and the Wabash rivers flow together. Their commander sensed an ambush in the making, despite the promises of a truce by Tenskwatawa - chief of the Shawnee – just the previous day. Several hours before dawn, the war cries of the Shawnee and other confederated warriors, accompanied by bullets, confirmed he was right.
The commander, William Henry Harrison – later known as “Ole Tippecanoe” and who eventually became the ninth President of the United States – became famous for the events that took place that fateful morning. In the end, 62 soldiers and officers were dead, with another 100 wounded. Although the actual Native American casualty count remains unknown, the biggest damage was to their spirit. The confederacy formed by Techumseh and his brother Tenskwatawa “the Prophet” was effectively crushed at this site. Historians mark this as the first battle leading up to the war of 1812.
Almost 75 years later a fence was commissioned to surround the “Tippecanoe Battlefield” as it became known. An iron fence, started in 1873, with gates and some modest ornamentation was constructed in nearby Lafayette and assembled on the site of the historic battle. Built by “Thomas Harding, Contractor and Builder,” the fence surrounds the historic battlefield, and serves as a monument to the memory of those that fought and died there.
Constructed of 440 sections, each 8 feet in length, the fence surrounds the entire battlefield, running a length of almost three quarters of a mile. A large cast-metal eagle with a wingspan in excess of 6 feet perches on the archway of the main entry gate in the fence (Image 1). The fence is itself a monument, built at a time when “craftsman” truly described a man’s work. During assembly, pre-crafted vertical pickets were placed in the top, middle, and bottom horizontal rails of the fence, held in place with a small iron “bead” welded onto the picket (Image 2).
The rails are bolted to posts embedded into the soil. The corner and gate posts all contain filigree-style wrought iron. The gate latches were at once simple in design and construction, but robust enough to survive both use and the elements for decades. Over the years this historical fence has since served its purpose as both monument and marker. Countless visitors have come to this wooded park to learn the history of the battlefield, and to pay their respect to those that died here. In 1963 the Tippecanoe Battlefield was designated a National Historic Landmark by the National Park Service.
The current stewards of the battlefield and its monuments are the Tippecanoe County Parks & Recreation Board and the Tippecanoe County Historical Association. These two organizations agree that the fence, now nearly 135 years old, was in need of attention. Corrosion and the failure of previous protective coatings on the fence were the most obvious threats to the fence’s future (Image 3). In addition to nature’s effects, a car had skidded off the adjacent snow covered road and crashed into the fence, creating outright damage to six sections (Image 4). These threats, and the approaching bicentennial anniversary of the battle, highlighted the need to restore the fence and protect it for future generations.
Allen Nail, superintendent for the TCP&R board, was already in the midst of a campaign to gain funding assistance from the state of Indiana for the restoration. A little-known clause in the state constitution (Article 15, Section 10) states that, “it shall be the duty of the General Assembly to provide for the permanent enclosure and preservation of the Tippecanoe Battle Ground.” The TCP&R board acts as an agent for the general assembly, which was constitutionally obligated to provide the funding. With the help of local legislators, and a great deal of effort by all involved, the State Budget Committee was soon convinced of their obligation to this preservation effort.
As part of the effort to examine the available options for restoration and preservation the board contracted Thomas M. Meredith, Architect, LLC. Meredith evaluated the latest technology available for the protection of iron structures. A coating system recommended by Sherwin Williams Industrial and Marine Coatings would eventually prove itself worthy of the application, and provide many years of protection once applied to the fence. A properly applied system consisting of a zinc-based primer (for cathodic protection), followed by a fast cure epoxy (for impact resistance), and finally a top coat of hi-solids polyurethane (for color and finish) would create a lasting coating capable of withstanding the elements for many years to come. The life cycle of this package has been proven on countless bridges and similar structures. As with most painting applications, proper surface preparation is critical to the success of the coating’s application. In this case it was determined by Sherwin Williams that an SP-6, “near white metal” finish was required prior to coating.
With the coating process decided, the next step involved evaluating the actual means of applying it. Several companies that specialize in restoration of iron fences were contacted. It was soon apparent that these firms preferred to do the re-finishing in their factories. This involves cataloging the parts; disassembling the pieces; shipping the lot to the factory; chemical stripping of the paint and de-rusting of the iron; coating the cleaned parts; return shipping everything and, lastly, reassembling the structure. There was little doubt the cleaning and stripping could be accomplished in a factory setting, but at what cost to the fence and the battlefield?
The way this fence was constructed it is rigid when in place, but very flexible and prone to damage if disassembled. Further, the bolts and nuts used in the original construction - historically significant themselves - would surely be damaged in the disassembly process due to their corroded and fused state. Lastly, the fence had actually become a part of the battlefield grounds. The trees in the battlefield area are in very close contact with the fence (Image 5). In fact, in some areas the fence is actually embedded in the trunks of growing trees (Image 6). Due to the intrusive nature of this method of restoration, Thomas and the board determined that this would be inappropriate for a monument of this nature and significance, and another search began.
In early 2008 the team contacted Grand Northern Products, a manufacturer and distributor of metal finishing processes. GNP was convinced that the project could be done in place, with minimal impact on the battlefield, and – most importantly – limiting the damage to the fence itself. By using the proper stripping method, and containing the process, preservation of the fence would be possible, without sacrificing the integrity of the monument.
Media blasting involves “throwing” abrasive materials with compressed air at a surface to clean it. Blasting would allow the fence to be stripped and coated on-site and in-place. Containing the blast process and providing a controlled environment for the coating process would both be challenges. The bigger concern with this on-site option was the possibility of damaging the iron with an over-aggressive blasting process.
Severe damage can occur with typical hard abrasives commonly used for blasting of iron structures. Traditional sand blasting would be too damaging to the historic fence, not to mention the forest and park. Sodium bicarbonate, commonly known as baking soda, had a short, but well-earned, reputation as an abrasive that could remove coatings without damaging delicate substrates. The process, if proven acceptable, would be ideal for blasting the fence in-place.
By February, the process had been tested at a local contractor’s shop on one of the gates that had been removed for other repairs. It was immediately apparent that the baking soda media was able to remove paint and surface corrosion. This was, however, not enough to meet the SP-6 requirements of “near white” metal. The addition of a small percentage of aluminum oxide to the mix was all that was required to meet the SP-6 specifications. In most areas a mixture of 90 percent baking soda and 10 percent aluminum oxide was sufficient to meet the requirement while removing minimal excess metal. In areas of excessive rust, mixes of up to 50 percent aluminum oxide were tested. Although the blasting proved very effective, it was apparent to all that an effective means of containment would need to be employed.
The state of Indiana provided the funding for the restoration of the battlefield fence, so they set the rules. After review by their historical review board, they approved the specifications of the blast media and the coatings package. Soon after, bids were sent out to qualified contractors. By late spring of 2008, the bids were opened and a contract was awarded to general contractor J.R. Kelly Company, Inc. of Lafayette for the restoration of the fence, with their sub-contractor Shelby Coatings of Shelbyville, Ind., to perform the blasting and coating operations. The winning bid was just over $650,000; small by government standards, but a great victory in the campaign to preserve the monument.
The hands-on work of restoring the fence officially began on June 30, 2008 (Image 7). It was determined that two sets of 90-foot-long scaffolding would be set up end-to-end over the fence. These two long sections were wrapped in reinforced plastic, creating two contained areas – one section for blasting, one section for coating (Image 8). Each section was placed under negative pressure using axial fans and dust socks to “turn over” the air and capture the process debris (Image 9). Blasting would take place in the first containment.
A double venturi nozzle (#7) was used for the blasting at 90 PSI. Blasting air was provided using a portable diesel air compressor (375 CFM). When blasting of 80 feet of fence – 10 sections – was completed, the fence was thoroughly “air washed” with compressed air delivered through the blasting system. The blasting then moved into the next containment to proceed, leaving the prepared fence ready for the coating process (Image 10). The galvanizing primer, epoxy base layer, and polyurethane top coat were all applied using spray gun methods. When the coating process was completed, the trailing containment was then moved forward of the blasting section to repeat the process (Image 11).
Progress proved to be steady. While work was not scheduled during rainy days, the shelter of the containment sections provided the ability to continue work on days with unexpected weather. A crew of five or six blasted and repainted an average of nine to 14 sections per day, depending on the percentage of rust and old coatings to be removed. By Thanksgiving the project was approaching its end. The use of the containment sections had allowed the blasting and coating to be done while the park remained open to the public the entire time (Image 12).
Impact to the environment was absolutely minimal. According to Jason Strassburg, project supervisor for Shelby coatings, “Deer and other animals were a constant reminder that this job was in the woods, and the people, always friendly and encouraging, a reminder that this was a public park.”
Work in the park proved to be a refreshing change from the average jobsite. “There were no squabbles, we all had the same goal – everyone involved in this project worked hard to do the best job we could,” Strassburg said. TCP&R Superintendent Nail described the effort as, “A project without animosity from beginning to end.”
Everyone involved with this project felt a sense of pride and accomplishment with the completion of the fence restoration. Battlefield visitors are overwhelmingly supportive of the restoration.
“The results that we achieved were beyond anything we expected at the outset,” Nail said. “The blasting proved capable of finishing the fence, with minimal damage to fence or battlefield, and the coating is appropriate to this monument, protecting it for generations to come.”