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Author Topic: A lesson by the BM online  (Read 848 times)

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Taras

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A lesson by the BM online
« on: January 06, 2013, 10:44:27 am »
AES Grave 11.72 grammes

An interesting description of conservation and cleaning by the British Museum:

http://www.britishmuseum.org/research/search_the_collection_database/search_object_details.aspx?objectid=1172631&partid=1&searchText=aes+grave&fromADBC=ad&toADBC=ad&titleSubject=on&physicalAttribute=on&productionInfo=on&numpages=10&images=on&orig=%2fresearch%2fsearch_the_collection_database.aspx&currentPage=8

Treatment date
7 February 2007

Treatment proposal
Stabilize - chemically and physiaclly. Clean, repair and support as neccessary.

Condition
Objects are actively corroding. Surface covered in friable lead carbonates which have disrupted surface detail and decoration.

Treatment details
The objects were degreased and delacquered by soaking in acetone.

The objects were treated by consolidative electrolytic reduction, in a 5% solution of Sodium Carbonate. The objects were wired up as the cathode to the negative terminal of a Standard Museum Laboratory Power Unit MkVI galvanostat with tinned copper wire and lead strips and the counter electrodes or anodes were Molybedenum steel sheets. The treatment was started at 300mA and reduced to 50mA over the course of the treatment to prevent evolution of hydrogen. The treatment took 204hrs in total. The reaction was continued over night but the objects were removed at weekends and soaked in a slightly acidified wash water.

After reduction, the objects were neutralised in a pH 3-4 solution of sulphuric acid in distilled water for 30mins-1hr. They were then rinsed until neutral and dewatered by rinsing with acetone and left to air dry.

The surface of the objects were consoildated/lacquered with a 5% solution of Paraloid B72 in acetone and if fragmentary were readhered with HMG Paraloid B72. The objects were renumbered, photographed and, if decorated, drawn.

 

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