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Thursday, May 29 • 2:30pm - 3:00pm
(Wooden Artifacts Session) Roccoco Drama - Dry Ice Cleaning the Ormolu Mounts of the Augustus Rex Writing Cabinet

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The Augustus Rex writing cabinet was made c.1750 for Augustus III, Elector of Saxony, possibly by Michael Kümmel, based in Dresden. The Victoria & Albert Museum acquired the cabinet in 1977. It had been completely restored and the ormolu mounts were regilded, though not recoated.

The cabinet’s bright appearance was at odds with the other objects in the gallery into which the cabinet was put on display. To remedy this difference, a thick layer of black-pigmented waxy material was applied to the mounts and surrounding wood. Thirty years of London dirt and grime blown in by the climate control system then settled into this layer.

In 2011 the cabinet was brought to Furniture Conservation for treatment during the renovation of the Europe 1600-1800 Galleries. As it would be one of two star objects highlighted in the Galleries, the curators wanted to bring Rex back to its Rothschild-era state of gleaming beauty.

The treatment of the one hundred and fifty ormolu mounts was particularly challenging. They are of the highest quality and detail, with incredibly fine chasing. The intractable wax was impossible to remove from the tiny crevices of the surface, and attempting to do so was not only overly time-consuming but caused damage to the regilding on the high points.

It was decided to clean the mounts with dry ice. This technique employs tiny pellets of dry ice (solid CO2) which are shot at the surface with the use of compressed air. The dry ice instantly sublimes upon contact with the surface, expanding by five hundred times and thus mechanically removing any soft surface coating. One major advantage of this technique is its ‘greenness’, as it utilises recycled CO2 instead of the gallons of solvent which otherwise would have been required.

The treatment was successful, removing the unsightly wax from the crevices of the chasing and leaving behind a clean but appropriately aged surface. Examination under magnification revealed that no damage had been caused to the gilded surface, some of which was highly burnished. In addition, cleaning of the one hundred and fifty mounts was accomplished efficiently and at low cost.

While dry ice was a good choice in this case, it is not appropriate for every surface or for every cleaning problem. Further study is warranted as well to confirm on a molecular level that no damage is being caused to the object surface.


Catherine Coueignoux

Associate Objects Conservator, Fine Arts Museums of San Francisco
Catherine is an Associate Objects Conservator at the Fine Arts Museums of San Francisco (deYoung and Legion of Honor). Prior to this she spent seven years in the Furniture Conservation studio at the Victoria and Albert Museum, first as a two-time Samuel H. Kress Conservation Fellow... Read More →

Thursday May 29, 2014 2:30pm - 3:00pm PDT
Regency Room