PLASTER CASTS AND CORROSION AN EXPERIMENTAL STUDY ON REMOVAL OF CORROSION PRODUCTS FROM PLASTER CASTS
Abstract
Conservation of plaster casts is complex due to the nature of the material itself. Corrosion of
armature and metal structural supports is one of the most common causes of damage in
plaster casts and subsequent corrosion staining. This study examines the use and efficiency
of different cleaning systems in removing corrosion staining from plaster casts. Three
different carriers were employed - commercial grade liquid latex, Arbocel® and xanthan gel -
all in combination with varying concentrations of chelating agent EDTA. Evaluation of
efficiency was based on ease of use, removal of corrosion products and damage to the
plaster substrate. A combination of colorimetry, visual examination and documentation,
microscopy and XRF analysis was used to evaluate results.
Results of this study demonstrate that corrosion staining in plaster casts can be treated
efficiently with xanthan gels and Arbocel® poultices, albeit some original material may be
removed in the process. The influence of prior cleaning and condition of the plaster object
itself proved highly relevant. Latex cleaning systems proved unreliable and difficult to control
on break edge surfaces; systems left residue and overall removed an excessive amount of
original material. Arbocel® systems indicated the most potential; comparatively less damage
to the plaster substrate and efficient removal of corrosion products.
It is further concluded that a combination of XRF and microscopy as a means of evaluating
cleaning systems provided more supplementary data than colorimetry values - due to the
surface stratigraphy of the experimental material and uneven severity of corrosion staining,
reliable values were difficult to obtain.
Furthermore, results of this study strongly suggest that surface stratigraphy, substrate
condition and extent of staining is highly relevant when choosing a carrier for delivering
cleaning agents.
Degree
Student essay
Other description
Degree project for Bachelor of Science with a major in Conservation with Specialisation in Conservation of Cultural Heritage Objects 2023, 180 HEC
Second Cycle
2023:34
Collections
View/ Open
Date
2023-11-07Author
Zimmerman, Gabriella
Keywords
plaster cast conservation, iron corrosion staining, xanthan gel, Arbocel®, latex cleaning, chelating agents
Series/Report no.
ISSN 1101-3303 2023:34
Language
eng