A Dangerous Friend: the Characterization and Treatment of Cadmium Formate Corrosion Identified on an Assemblage by Edward Kienholz

The Friendly Grey Computer‐‐Star Gauge Model #54 by Edward Kienholz exemplifies the artist’s assemblage practice, where he constructed sculptures using found materials, including various industrial metal elements. Stored intermittently in a wooden crate for 45 years, the sculpture exhibited white, crystalline efflorescence on several metal components. The unknown efflorescence was characterized using ultraviolet-induced fluorescence (UVF), micro-Fourier transform infrared spectroscopy (µ-FTIR), Raman spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and handheld X-ray fluorescence (p-XRF) to inform treatment and long-term preservation. It was identified as cadmium formate dihydrate (Cd(HCOO)2 · 2H2O), a hazardous corrosion product resulting from cadmium-plated metal fastenings used in the sculpture. Solid-phase microextraction (SPME) coupled with gas chromatography – mass spectrometry (GC – MS) of the microclimate inside the crate showed the presence of formic acid, the likely cause of the formate species. The cadmium formate dihydrate was reduced with safety precautions in place, and the sculpture was rehoused in a newly constructed wooden crate lined with Marvelseal 360 to limit the emission of volatiles within the crate over time. Results from this study highlight where cadmium formate dihydrate can be found within heritage collections and provide insight into Kienholz’s artistic practice.