- THE MAGAZINE
The Hightstown Historic Preservation Commission (HHPC) from the Borough of Hightstown, New Jersey was charged with overseeing a $1.7 million streetscape project funded by the American Recovery and Reinvestment Act. Restoring a Civil War memorial was part of the project.
The monument was erected in 1875 and is engraved with the names of 35 soldiers. The 23-foot-high obelisk is carved from unpolished white Italian marble, and rests upon a large block of American granite in tribute to the local heroic volunteers. Beneath the monument, resting upon granite blocks, are four Confederate Parrot guns known as the Brooke-type cannon.
The ProblemAs part of the overall project, the HHPC wanted to restore the monument to its original state in preparation for the 150th anniversary of the Civil War. The monument had never been cleaned; it sits in a triangular park between two streets, and was coated with 136 years of traffic grime, minerals and dirt. In fact, the granite eagle at the top of the monument, once white, was completely black.
The detailing on the monument was a big concern. The seals of the United States, New Jersey and Mercer County are chiseled into the white marble above tablets bearing soldiers’ names. The front exhibits full-size carvings of a Springfield rifle, a sword and standard. In addition, the marble eagle sitting on top of the monument has very delicate wings. Many areas on the monument – some carved as thin as 1/8” – were cause for concern for those in charge of the restoration. “We were very worried about the potential of damaging the structure during cleaning,” Buriak said
The SolutionThe contractor, USCleanBlast.com, suggested dry ice cleaning. Dry ice media, blasted using pressurized air, sublimates upon impact with the surface being cleaned, lifting away dirt and contaminants safely without leaving behind any secondary waste.
Using a Cold Jet Aero 40, Tom Monacelli, field supervisor at USCleanBlast.com, was able to successfully clean the monument’s carved surfaces. The dry ice cleaning easily lifted contaminates without leaving behind any secondary waste.
Most of the structure took only one pass to clean off. Where there was green moss or algae, a second pass completely cleaned it off.