Hello, my name is Yasmeen, and I am one of the students from the Hassanamesit Woods field school in Grafton this year. As an anthropology student from UMass Boston completing her last year, I think it was a wonderful experience to have been a part of. Some of us have gone on to do a lab course after the field school wrapped up. The lab is where we get to clean the artifacts we found and see them in a new way. After they have been cleaned, one can determine what steps are necessary in preserving the artifacts.
One method we learned is iron conservation. We find quite a few iron objects at the Sarah Boston Site, and when they come out of the ground, they are always rusty and in some cases, corroded beyond recognition. Since the metal is fragile, it must be treated with care. By conserving the metal, we are helping to prevent it from further corrosion and deterioration. It will not look as it originally did, but it can be preserved in its current state. We found items such as kettles, lamps, tools, nails, eating utensils, and buttons. These objects provide a powerful material connection with the past and help us piece together what life was like for Sarah Burnee and Sarah Boston on Keith Hill in the late 18th and early 19th centuries.
There is a specific way metal objects must be treated when being conserved. The first step is to soak it in a container filled with distilled water. While it soaks, we gently brush the object with a small wire brush. Doing this helps to remove some of the dirt that has accumulated over the years. The tub is refilled as needed, and the gentle brushing away of the dirt is repeated until the artifact is cleaned.
Once the dirt is cleaned off, we can begin to remove the rust. This is done very carefully and delicately, as metal in this state can be easily damaged or broken. The removal of rust can be done with tools such as very small chisels, dental tools, and small, scissor-like tools called forceps that are used to “crunch” the rust nodules off. This process requires diligence, because getting the rust off can be tricky. Because these objects are so old and sometimes rusted completely through, the lab technician must remove the rust cautiously, so as not to compromise the integrity of the object as a whole. We often use references to get an idea of the original shape of an object, so we can preserve its original form as much as possible.
Once the rust has been removed completely, the next step is to apply a 10% tannic acid solution to the artifact. The solution, when introduced to iron or iron oxide (rust), hardens and dries, effectively suspending the oxidation process and giving the conserved iron artifacts a shiny black surface. The application is usually done with a small wire brush that resembles a toothbrush. The brush is dipped into distilled water in between tannic brushings to avoid cross-contamination. The object is brushed completely with this solution and allowed to dry at least three times, followed by a period of five or so days to observe how the artifact is reacting to the treatment. If necessary, the process is repeated until no further rusting is visible. When the object turns completely black, the rusting process has been sufficiently halted, and the conservation is complete.
I found metal conservation to be very educational and interesting. I believe that it is a great way to see the care and methods that go into the preservation of these precious objects. Thanks for reading, and I hope you enjoyed learning about the process as well!
By Yasmeen Abdaluah