Author: Sylvia Schweri

Mark Erdmann, Conservator of Objects, ICA Art Conservation; Adam Jenkins, Conservator in Private Practice; Robert Marti, Co-Owner, and Marianne Russell Marti, President, Russell-Marti Conservation Services, Inc.
Presented by Mark Erdmann, this talk described the treatment of three versions of Claes Oldenburg’s Three-Way Plug sculpture by three separate conservators.  Erdmann treated the Allen Art Museum’s (AAM) version in Oberlin, Ohio; Jenkins treated Philadelphia Museum of Art’s (PMA) version; and Rusell and Russell Marti treated the Saint Louis Art Museum’s (SLAM) version. While working separately, the authors shared their experiences with each other, and seized a great opportunity by aggregating these experiences in one place to be referenced by others faced by similar challenges.
The outdoor sculptures consist of Cor-Ten steel and bronze plug prongs, assembled with no internal armature.  Uncoated at installation, the sculptures are sunk into the soil on gravel beds with no platforms, and contain drainage holes.  The authors’ research revealed interesting insights into Oldenburg’s intentions, both in installation and fate of the multiples; he wanted the Plugs to deteriorate in relation to the environment, and hoped they might end up in dramatically different environments that might shape their appearances.  This was not to be, and the sculptures experienced similar patterns of deterioration, primarily caused by accumulation of moisture and debris on the sculptures’ interiors.  Each Plug had been previously treated for corrosion at least once and given protective coatings.  Corrosion of the PMA and SLAM versions was most severe, with areas of localized steel collapse.   Galvanic corrosion also occurred at the interface of the bronze prongs and adjacent steel, and localized tarnishing was found on the prongs.
Treatment of all three Plugs involved removal of existing coating and corrosion, followed by coating reapplication.  The SLAM and PMA Plugs required partial replacement of the Core-10 body in areas of collapse, with patches welded in place following applicable ASTM standards and textured to match the original.  The AAM’s Plug was cleaned with glass bead peening, followed by coating with an epoxy coating.  The SLAM version was cleaned by sand blasting, followed by coating with a zinc primer and acrylic/polyester/polyurethane topcoat.  The PMA’s Plug was also abrasion-cleaned, followed by coating with a Tnemec Co. zinc urethane primer and epoxy topcoat.  The most notable difference in approach was that of treatment of the interior – while the interior of AAM’s Plug was coated overall with Ship-2- Shore marine coating containing corrosion inhibitor, the interior of the SLAM’s Plug was only locally coated, and the interior of the PMA’s plug was left uncoated in favor of ongoing maintenance and inspection.  It will be interesting to compare preservation outcome of the three in relation to this difference in approach.
To address deterioration due to galvanic corrosion at the prong’s bronze-steel interface of the AAM’s version, joins were strengthened via TIG welding.  The authors acknowledged this would not remediate the problem, but solutions involving disassembly and isolation of the metals were financially unfeasible.  Cathodic systems for overall corrosion protection were likewise financially out of reach, and difficult to monitor over the long term.  In each case the prongs were cleaned and re-coated, and drainage was improved.  Most importantly, each conservator recognized that frequent inspection and removal of debris from the interior was key to the preservation of the Plugs, and emphasized this to the owners.

Presented by Catherine Williams, the talk started with a warning for more sensitive viewers – alluding to forthcoming descriptions of welding, an uncomfortable proposition for many conservators.  The Menil Collection in Houston, Texas conserved a collection of sculpture by John Chamberlain in preparation for the museum’s 25^th anniversary in 2012.  Ranging from 8 to 22 feet in height, Chamberlain’s sculptures are composed of multiple pieces of salvaged sheet metal covered with layers of original automotive and applied artists paint, joined by mechanical fasteners and tack welds.   Several sculptures were structurally unstable due to the spontaneous nature of their assemblage, with poorly prepared surfaces and poorly executed oxyacetylene welds. (The authors observed that the quality of welds improved after around 1981, when Chamberlain’s assistants executed more of the welding.)  Paint (both the artist’s and original automotive) was lifting and flaking, and the sculptures were dirty.
Chamberlain’s studio was consulted over the course of treatment planning, but played a limited role in part due to the artist’s death in 2011.  An interview with Chamberlain archived through the Artists Documentation Program offered guidance in terms of the artist’s priorities, especially in terms of aesthetic reintegration. In the end, it was determined that adhesives would not be sufficient to stabilize failed joins, and Chamberlain’s studio concurred with the conservators that welding would be an appropriate solution.  The conservators contacted Guido Schindler of Schindler Metalworks in Houston to execute TIG weld repairs.  It was emphasized by both the authors and responding audience members how much the eventual success of these treatments depended on the expertise of this highly skilled craftsman.
In executing the welds on four sculptures, Schindler added welding rod only where necessary, working around existing slag on surface and retaining the original welds’ “messy look.”   In response to priorities expressed by the Chamberlain in an interview, artist’s paint was given priority in reintegration, though both the artist’s and automotive paint layers were stabilized.  Balanced cleaning of the pastiche sculptures with so many contrasting surfaces proved a challenge.  Careful documentation of each sculpture included painstaking numbered mapping and description of each intervention.  In all, 20 sculptures were documented, 12 were cleaned, and 4 were structurally stabilized in preparation for exhibition.