Conservation of Anglo-Saxon finds

Recently Pieta has been working on finds for Bucks County Museum. Discovered by a metal detectorist and donated to the museum, the collection is an assemblage of two copper alloy vessels (a bowl and a bucket) and two spearheads from the 5th/6th century.

Objects before conservation. Bucket (top right), bowl (top left)

Because they were reported through the Portable Antiquities Scheme, the finds were able to be excavated by the local Finds Liaison Officer (@Bucks_FLO), which allowed the maximum archaeological information to be gained- including spatial information on how the objects were buried.

Arwen James: Buckinghamshire Finds Liaison Officer. Excavation images from Twitter 

The primary aim of the conservation treatment was to ensure the finds were stable- newly excavated finds can sometimes begin to corrode as they adjust to the higher levels of moisture and air outside the burial environment.  The second aim was to clean and reconstruct the vessels as far as possible and clean to spearheads to reveal their original shape. Both vessels were heavily damaged on the rim due to a plough.

To have a closer look at the objects without removing any of the soil, an x-ray was taken. This also ensured that there were no further objects hidden inside the vessels.

X-rays of finds. Bucket (top right), bowl (top left)

To reveal the vessels the soil was micro-excavated. This involves slowly removing layers of soil so that all small loose fragments of the vessel can be recovered and any possible organic materials are identified. The removal of soil also showed the full extent of the plough damage and the iron handle on the bucket.

Vessels during and after micro-excavation. Bucket (top), bowl (bottom)

The vessels were slowly cleaned with cotton swabs with solvent (acetone with a few drops of distilled water added)- this allowed a controlled clean without any danger of scratching the metal surface. It took three days to remove the soil from both vessels.

A dramatic colour change to the surface as the soil was removed. Both images of the bowl.

During cleaning you often find little hidden details, such as this old repair inside the bucket. It’s rewarding to see how this vessel was used and valued during its lifetime.

Once all fragments were cleaned, the reconstruction of the loose fragments could begin. The walls of the vessels are very thin (0.3-0.5 mm thickness) so the fragments were clamped and a small piece of Reemay (a synthetic fabric) was applied to hold the joins together.

Bucket edge fragments during reconstruction

Once all of the fragments were reattached the Reemay had a slight white appearance in places. As this is visually distracting when looking at the vessels the white areas were over-painted with conservation grade acrylic paints. Caution was taken to only apply paints on the Reemay and not on the original object surface itself. 

Bucket with Reemay colour-matched 
Bowl after conservation
Bucket after consevation

Once the vessels were completed, the conservation moved onto the spearheads. The corrosion and attached small pebbles were removed with an air-abrasive- this technique uses very small particles of aluminium oxide to clean the surface. It’s a lot like a tiny sand blaster, but allows the slow and delicate removal of the corrosion so no damage takes place to the original surface.

Spearheads before conservation
After conservation

Now that the conservation is complete the objects will return to Bucks County Museum. It’s always a privilege to work on such wonderful objects.

Before and after conservation