Date completed : 28 February 2019 Duration : 8 Months
Graciela Ainsworth

Following the 2014 fire the GSA decided to complete conservation works to specific very fire damaged plaster casts that in part just survived the 2014 fire and became important historic artworks.

We completed trials and analysis throughout the project, from analysis of the different surfaces of the casts, to CT scans of the plaster substrates, which included finding out the approx temperatures that the gypsum plaster had reached during the fire of at least between 130 and 180% C, and this was really important for the decisions on the different conservation works. 

The analysis also included endoscope, thermography and X ray. Through these forms of analysis and throughout our conservation works we learnt that each cast had different surface applications, from very little surface layers remaining to impervious bright pink layers found on Mercury, and very different substrate manufacture, different thickness of plaster walls, some areas hollow, some areas solid, some with internal armatures, and some without, and different forms of armatures from hessian to wood to metal.

We had the challenge of consolidating structurally from the inner substrate out. Our inspection found the large plaster casts to be hollow, yet the plaster gysum wall thickness varied from 5 mm to 40mm, with parts of the lower sections to be solid gypsum with hidden internal metal armatures. The actual gypsum hollow shells were very fragile and brittle and required consolidation work.

The visual surface patina was not just in colour but also in texture, and respecting the process that had occurred, we even grouted inside all the raised bubbles using hyperdermic syringes and needles, filling the spaces between plaster substrate and paint.  Our processes encompassing building and medical tools. The final treatment was to protect the new fire damaged surface patina.

The conservation work was a huge challenge and Final Reports with all analysis were documented for the GSA. Then the second fire of 2018 happened, and sadly the Laocoon was lost to the fire, but his hand which had been stored seperately was found, and this is the only physical remains of the plaster cast, and therefore even more emotive, and we were asked to make a display for it in 2019. Luckily we had moved the smaller GSA fire damaged plaster casts to our Edinburgh workshop, and therefore the figure of Mercury and all the Cantoria panels survive and have been returned to the GSA.

The whole project was lead by Polly Christie GSA Recovery Project Lead, Archives and Collections. She has continued working with the Laocoon plaster cast in a virtual form with designers and the GSA now have a virtual historic memory of the Laocoon plaster cast.

After GSA fire 2014
GSA Mercury plaster cast before 2014 fire
During conservation work of GSA Mercury plaster cast in our workshop
GSA Mercury after conservation
GSA Laocoon before 2014 fire
GSA Laocoon plaster cast after fire 2014
Themography analysis during conservation of GSA plaster cast Laocoon
During conservation of GSA Laocoon
GSA Laocoon after conservation work before fire of 2018
All that remains of GSA Laocoon is his hand 2019 after two fires 2014 and 2018

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