41st Annual Meeting, Object Session, May 30th, 2013. “Three-Way Plug Three Ways: Conservation Treatments of Three Editions of Claes Oldenburg’s Cor-Ten Steel and Bronze Giant Three Way Plug.”

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.