Stuck like glue: Wood tar as a medieval stone adhesive
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https://hdl.handle.net/11250/3119282Utgivelsesdato
2023Metadata
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Originalversjon
Ebert, B., Bjelland, T. (2023). Stuck like glue: Wood tar as a medieval stone adhesive. I: Working Towards a Sustainable Past. ICOM-CC 20th Triennial Conference Preprints, Valencia, 18-22 September 2023. International Council of Museums Committee for Conservation (ICOM-CC).Sammendrag
This study outlines a medieval stone repair technique involving wood tar. In the process of condition assessment, an unusual adhesive was identified used for repairs and indents on Stavanger Cathedral, a medieval Norwegian soapstone structure. Based on appearance and context, an initial hypothesis was formulated that tar may have been used as a historic repair method. This hypothesis was subsequently tested and confirmed through analysis. Samples of the adhesive were investigated using light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy and gas chromatography–mass spectrometry. The material was radiocarbon dated and the date found to coincide with the reconstruction of the choir following a fire in the latter quarter of the 13th century. Several hundred findings of tar repairs have so far been identified on the cathedral, indicating comprehensive use of tar as a medieval adhesive for soapstone. These findings have implications for the development of an alternative conservation adhesive based on traditional materials.