Voices from the Field (2019-07-01)

Later

Elena Mars & Leah Balagopal

The conservation lab treats a variety of objects, but this week our focus is metal! Because Kaymakçı is a Bronze Age site, the metals we see are usually either copper alloys or lead. Archaeological metals can be found in varying states of deterioration due to past use, burial, environment, and the excavation process. Luckily most recovered metals are in good condition with no active corrosion.

Metal objects are typically covered with a layer of burial accretions (calcium carbonate rich material that is naturally deposited) and soil that obscure the form and surface of the object.

Accretions or calcium carbonate coatings that develop during burial

 

Accretion removal is a delicate process which entails first removing any loose soil with a stiff brush. To tackle the accretions, we turn to the scalpel. Slow mechanical cleaning with a thin blade coupled with a few drops of ethanol can free soil trapped within layers of accretions, thus removing them both. We also use unorthodox materials to safely remove surface layers including porcupine quills.


Our tool kit! Including porcupine quills found on site at Kaymakçı. The quills are used to mechanically remove unwanted surface deposits.
On this copper alloy a glass bristled brush was used to aid accretion removal while preserving the protective and stable malachite oxide layer.
Once the obscuring accretions have been removed the form of the needle is revealed.
On the left: before treatment; On the right; after treatment.
Elena treating a copper needle under the microscope.
Leah treating a copper awl –a puncturing tool.

Our conservation team is working hard to conserve the artifacts from the site and hope to “Cu” Later!

Look forward to more posts from Gygaia Projects over the course of the year!

Posted in Conservation, Uncategorized.