Coaxing artifacts into giving up their ghosts

by Meghan Smith, Conservation Specialist

In 200 years, what kinds of everyday objects will illustrate our lives for archaeologists and historians? Perhaps iPads or cell phones will be the most compelling emblems of 2012. But looking back two centuries, things were undoubtedly simpler.

This month, our state historic site at New Harmony unveils a new exhibition featuring objects from the daily lives of its early citizens. Most of the artifacts come from archaeological digs, and look a bit worse for wear after spending so many years in the dirt. Metal objects, in particular, tend to suffer; environmental factors like oxygen and water cause damage. When they come out of the ground, these metal artifacts are covered with a hard crust made up of corrosion and matrix (which is a fancy term for the dirt around the object). While the damage can never be completely reversed, some of the crust can be removed so that the object underneath is a lot more recognizable.

But getting the corrosion and matrix to give up the ghost isn’t easy. When the objects for this exhibition first came to our lab, some of them were barely recognizable. “Wait, that’s a fork?” I asked, pointing to a lumpy-looking thing. “Yup,” said Bill Wepler, our archaeological curator. “It’s in there somewhere.” That fork and the accompanying knife, pictured below, were the most challenging artifacts we worked on for the exhibition.

Image of the knife and fork prior to treatment.

Removing the matrix and reducing the warty corrosion layer while preserving  the underlying object is tricky, time-consuming work. The unsightly corroded metal surface often detaches along with stable surface layers below, so we have to get as close as possible without actually removing any of the desirable surface of the object. Most of the work is done with scalpels, pin vises and brushes. Magnification and powerful lights are necessary in order to see in as much detail as possible. Still, as careful as we might be, things happen. Minute cracks in the object will cause one area to weaken while a nearby spot is worked on. Wicking adhesive solution into the crack helps stabilize the object, but bits will inevitably fall off. When they do, we carefully re-adhere them to the object.

During treatment, the fork’s bone handle came apart. Not to worry, fork: there is an adhesive treatment in your future.

Once we’ve removed as much of the matrix and corrosion as possible, the last step is to apply a thin layer of consolidant to the whole surface of the object.  The consolidant used is a specially formulated acrylic coating that stops any more corrosion from building up because of exposure to moisture; it also helps prevent any more pieces coming loose.

So, after a lot of hours spent peering through a magnifier and picking away bits of dirt and rock, the knife and fork look a lot more recognizable! You’d never mistake them for something out of your own cutlery drawer, but that’s part of their history. They’ve been indelibly marked by many years spent in the Indiana soil.

The finished product, on display in Community House No. 2.

And now the knife and fork, along with dozens of other archaeological objects, are on display at the New Harmony State Historic Site! It’s a beautiful place to spend a day or two, so head on down to discover another chapter in Indiana’s story.

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