My name is Jake Harding. I am an intern at the Iziko Museums of South Africa working in the Historical and Maritime Archaeology section. We are currently working on three major projects, each of which is at a different stage. This means that in the course of a day my duties are varied, both in terms of site and focus.
Our current sites are:
• Marion Island: An Island to the South East of South Africa with a history as a sealing station. This Island is also the site of a shipwreck that left its crew marooned for 3 months. We have a number of artefacts undergoing conservation from sites across the island.
• V&A Waterfront Grain Silo Shipwreck: A shipwreck was discovered during development of the Grain Silo Precinct at the V&A Waterfront early in 2012. This site included the lower parts of a wooden vessel (such as the keel, some planking and the lower frames) and a large number of iron objects including cannonballs, pieces of machinery and currently unidentified fragments. The majority of artefacts currently being conserved in the lab come from this site.
• Clifton Site (Sao Jose): Possibly the wreck site of the slave ship Sao Jose, the Clifton site is currently our primary field site. We have a small collection of artefacts undergoing conservation including copper alloy spikes and a cannonball. Plans for the future are to retrieve one of the cannons from the site for conservation and study.
Our facilities include an office and resource library for research and organization, a dive store for our more specialist fieldwork gear, a ‘wet lab’ facility for artefact conservation that requires the use of chemicals, an outside area for the dirtier aspects of this conservation and a store for our collection materials.
I am not a morning person. As such I survive the beginning of each day with the comforts of routine. I come in at 8am. First thing to do is log on to my computer. To allow it time to get ‘towards itself’ I then do a round of the lab to check on the various artefacts that we are working on in order to observe any changes during the night. Is the barrel stave from Marion Island consolidating in its polyethylene glycol (PEG) solution? How have the iron objects from the V&A Silo wreck changed overnight? Once I have done my round I ask my boss, archaeologist Jaco Boshoff, if there are any developments in the planning of projects or if there are specific tasks that need to be performed today. This is the time when I source quotes for gear and conservation materials as well as perform any necessary correspondence, such as organizing a presentation at the Institute of Maritime Technology (IMT) next month.
Jaco planning projects
Once this is done with the practical side of my day starts. As we currently have so many iron objects undergoing conservation (almost 200) the majority of my time will be spent working on them. These objects are kept in plastic bins or PVC lined milk crates, each with a code to describe where the contained objects came from on the site (context is everything after all).
So how are we doing today?
To prevent the degradation of the objects through cracking and oxidation (rust), the artefacts are kept in a weak caustic soda solution (5-10%). This increases the pH of the solution which slows down the oxidation process whilst the solution helps to desalinate the iron. Desalination is the removal of chlorides that have permeated the metal during its time in seawater and is very important in artefact conservation as these salts both speed up oxidation of the metal and create cracks from expanding crystals.
The solution needs to be changed in order to remove salts that have already been washed out and most of my day is spent doing this. As archaeologists and conservators we must record what we do to artefacts in our care so that if someone else wishes to work on the artefacts they can see what has already been done. As such we test the condition of the objects by testing the pH and conductivity of the solution both before and after treatment in order to gauge the progress of the desalination process.
Once the initial test is complete I remove the artefacts from their solution and place them on a pallet for cleaning. The solution is disposed of and the container cleaned. Cleaning the artefacts themselves requires everything from hammers and chisels to brushes and hoses. When iron oxidizes underwater it often develops a layer of corrosion product called concretion. This material is fixed to the object and extremely hard. This is where the hammer and chisel come in. Great care is needed to remove the concretion however as not only do we not want to damage the underlying artefact but the concretion itself may hold fragments of smaller objects. Having removed the majority of concretion from an object it is time to brush off any loose corrosion layers or irrelevant organic material. This requires the brush, hose and fine detail hammers. Having cleaned the artefacts I return them to their container and fill it with water to a known volume.
Jake’s choice of weapons
This process is repeated for as many of the containers as I can do in a day. Once the last container is processed I add caustic soda to each to create a solution of known concentration (usually 5-10%). I give the solutions about 30 minutes to begin reacting and then go back to them in the same order that I added the caustic soda to test their new pH and conductivity.
Once this is done the results of the days recording are added to a spreadsheet for future reference.
I end the day with a final round of checking the artefacts to make sure everything is ok.