Saturday, May 31 • 10:30am - 11:00am
(Objects Session) Pine Pitch: New Treatment Protocols for a Brittle and Crumbly Conservation Problem

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The use of Pine Pitch as a coating has a long tradition. Various trees of the Pinus genus exude a thick liquid that can be heated and applied hot as a coating to American Indian baskets to make them water tight.

An item-by-item conservation survey and storage upgrade project funded with a Save Americas Treasures award provided access to over 4000 ethnological and over 20,000 archaeological baskets in the Arizona State Museum collections. Within the ethnology collections, over one hundred pitch coated baskets were survey examined. Nearly all were determined to be extremely unstable due primarily to severe oxidation of the pitch. Surfaces were characteristically, cracked, crizzled, brittle and crumbly. Entire surfaces at risk of imminent loss often accompanied by small zip-locking bags of crumbs placed inside the baskets revealed an urgent conservation need.

To prevent ongoing surface loss, these baskets were given conservation treatments mid-survey as triage. The treatments allowed the baskets to be moved on and into their new storage location without further damage and loss. This improved curatorial access for cultural location determination and initiated a study of further analysis and research on the materials of this technology by the conservation lab.

Designing a conservation treatment for so many similar examples prompted the development of protocols. A fine mist of ethanol was tested and used effectively to reactivate the damaged pitch and stabilize the basketry surfaces. Efficient and effective techniques for cleaning and securing the difficult surfaces during the process involved the use of brushes, Teflon film coated swabs and Kimwipes saturated with ethanol.

Self-sampled particles from all baskets were analyzed with Fourier transform infrared spectroscopy (FTIR). Standardized protocols were developed to analyze bulk samples, resinous extracts and inorganic fillers to note correlations with cultural, regional, temporal and stylistic differences that were collected with documentary information in the conservation database during the survey.

Conservation surveys have evolved greatly over the years at the Arizona State Museum. The conservation database provides more reliable information for researchers, curators, and conservators than the old catalog cards and the collection information system database. This is because the standardized information has been entered recently and by conservators focused on the entire basket collection. The survey, treatment, and analysis of the pine pitch baskets has allowed us to see patterns of manufacture among different cultural groups; changes in weaving techniques, container shape, and design use over time and geography; and sense of the expected forms of deterioration within museum collections. The project also informed our examination of archaeological examples of pitch coated items.


Christina Bisculca

Student, Materials Science and Engineering Heritage Conservation doctoral program, University of Arizona
avatar for Dr. Nancy Odegaard

Dr. Nancy Odegaard

Conservator, Patronato San Xavier
Nancy is the Conservator Emerita at the Arizona State Museum on the campus of the University of Arizona in Tucson where she is also a Professor Emerita of Anthropology. Since 1983, she led the effort to preserve the collections of the museum through loans, exhibits, excavations, research... Read More →
avatar for Marilen Pool

Marilen Pool

Project Conservator, Arizona State Museum
Marilen Pool is an Objects Conservator specializing in ethnographic and archaeological artifacts.  She is currently working as the Project Conservator on the IMLS funded “Conservation of Southwest Ceramic Vessels” phase of the Pottery Project.  She has worked previously in the... Read More →


Brunella Santarelli

Student, Materials Science and Engineering Heritage Conservation doctoral program, University of Arizona
avatar for Gina Marie Watkinson

Gina Marie Watkinson

Conservation Lab Manager, Arizona State Museum, University of Arizona

Madeleine Neiman

Graduate Student Intern, Arizona State Museum

Saturday May 31, 2014 10:30am - 11:00am PDT
Grand Ballroom B