The conservation of Kore (Acc.No.1045A-D4)

Bertram MACKENNAL
Tragedy enveloping Comedy (c. 1908) (detail)
marble
219.4 x 76.2 x 55.7 cm (overall)
National Gallery of Victoria, Melbourne
Presented by Mrs Brough-Bell, 1910
485-2
Bertram MACKENNAL
Tragedy enveloping Comedy (c. 1908) (detail)
marble
219.4 x 76.2 x 55.7 cm (overall)
National Gallery of Victoria, Melbourne
Presented by Mrs Brough-Bell, 1910
485-2

Following my last blog post  on the conservation work on the NGV’s Kore (Acc.No.1045A-D4) I have some updates to share.

 

After one of the previously mended breaks came apart, all remains of the old adhesive needed to be removed. This cleaning process is now largely completed and I can start planning for the next step in the conservation treatment which is to find a suitable adhesive. The Kore is made from white marble, which presents a challenge for conservators due to the colour and translucent quality of the material. While one can find adhesives that are clear, many do become unsightly over time due to discoloration. The other main consideration in the selection of the adhesive relates to it’s strength. For the repair of the Kore, a marble sculpture of large size (approx. 130cm tall) we need a long-lasting strong adhesive.

 

Typically thermosetting resins (such as epoxy resins) tend to be stronger and harder than other resins used in conservation and are the preferred adhesive for structural repairs of stone. However, once cured the resin is very hard and cannot be re-softened making the treatment irreversible and future adjustments impossible. This is a disadvantage and my preference is therefore to use acrylic resins.

 

Acrylic resins belong to the group of adhesives that are thermoplastic, meaning they can be melted with heat and moulded multiple times. Some acrylic resins are very popular in conservation as they have proven to be stable and non-yellowing, making them suitable as a coating, consolidant and adhesive. Recently acrylic resins have been extensively tested by a team of conservators and scientists in the United States for their suitability in the repair of marble sculpture and I have been talking to  this group/ these individuals about their findings and to get some practical tips.

 

Lastly, we need to find a suitable filler to bulk up the adhesive, which will take care of any larger gaps. We need to be mindful that any added material might impact on the properties of the adhesive and may also affect the aesthetic quality of the fill. As mentioned above we aim to match the translucency of the marble. A range of different fillers are available, but two of the more commonly used fillers are fine marble dust or glass microspheres. The glass microspheres (also called microballoons), are lightweight and I have used this material in combination with acrylic resin before and am very happy with the result.

 

Above is an example showing a previous repair and subsequent improvement using glass microspheres and acrylic resin on Bertram Mackennal’s Tragedy Enveloping Comedy currently on long term loan to the Art Gallery of Ballarat.

 

There are still a few practical aspects that will need to be resolved, but as I proceed with this challenging conservation project I will continue to share my experiences and report on the progress via the NGV blog.

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