Original and reformulated BEVA® 371: Composition and assessment as a consolidant for painted surfaces

Abstract

Many natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA^® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigation. This paper will discuss the development of BEVA^® 371, the chemistry, and roles of each component, and address a practical concern about the tack behavior of its replacement formulation, BEVA^® 371b.     

The treatment of ancient Portuguese tiles

Abstract

The preservation of the vast cultural heritage of tiles in Portugal requires the development of a systematic scientific and technological approach. In this communication the case of the treatment of a panel of ancient tIles is described. The main problem was the cleaning and consolidation of the piece, followed by restoration for exhibition. The treatment was preceded by a study of the materials, consisting of analyses of the ceramic body and the glazed surface. The removal of aged waxes and resins was achieved using appropriate solvents and the consolidation of the ceramic body was carried out by an inorganic treatment. For the reconstruction of missing parts and the mounting of the panel materials were chosen which would avoid interaction with the original material.     

SOME ASPECTS OF THE CONSERVATION OF WORKS OF ART IN BUILDINGS OF NEW CONCRETE

Abstract

This paper deals with the materials used in conservation treatments in the first half of the twentieth century for the preservation and consolidation of wooden art objects from the Saxony region in Germany. The use of such materials must be seen as early attempts to find a conservation treatment for wood. The documentation of conservation treatments provides a reference to the application of oils and oil–resin mixtures. The results from the chemical analysis of samples of historic preservatives from the beginning to the middle of the twentieth century (so-called 'Puckelin') carried out by gas chromatography–mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) analysis confirm the use of tung oil as a drying oil, whereas the use of linseed oil cannot be excluded. Colophony and, probably, amber varnish were used as resinous constituents. There are indications that a conservation material dating from the second half of the twentieth century most likely contained rapeseed oil.     

THE CONSERVATION AND TECHNIQUE OF SILVER BANGLES DISCOVERED AT ROJDI,INDIA

Abstract

The treatment of two silver bangles found at Rojdi and dated c. 2000 b.c. is described. The bangles were separated by removing the hard incrustations with a 20% sodium hexametaphosphate solution and 15% acetic acid. Silver chloride was removed with a 25% solution of 0.88 ammonia and a 20% aqueous solution of ammonium thiosulphate.

Silver sulphide was removed in a 20% formic acid bath. Polyvinyl acetate was used for consolidation, and a coating of polymethyl methacrylate was applied. The silver was found to contain copper and lead. The causes of embrittlement and the manufacturing technique are discussed.     

The repair of parchlllent: Filling

Abstract

Parchment is produced by processing the dermal layer of animal hide through limited mechanical and chemical treatment and then drying it under tension. The weak condition of many historical objects made of this material is caused by chemical, biological and mechanical degradation. Repairing these objects by filling gaps with parchment or paper patches may be inadvisable, due to important differences in intrinsic strength, which can create tensions between old and new materials. Alternative filling methods may be used, consisting of the application of solid materials in the form of a powder or a suspension, used to create a solid sheet of reconstituted parchment. The solids may consist of any kind of collagenous material (powdered parchment or hide, gelatin), paper or a combination of the two. Published methods describe preliminary treatments (e.g.relaxation), application media (water, solvents, additives), use of additional consolidating membranes (Japanese paper, goldbeater's skin), use of adhesives for pasting and surface consolidation purposes, preparation of mechanically isotropic templates for infills and tinting with synthetic dyes. A comparative investigation of methods confirms that the mechanical properties achieved in these infills, such as tensile strength and elasticity, as well as their reproducibility, are acceptable for application in conservation practice.     

Trust v. Antitrust

SUMMARY

The legal publishing industry in the United States went through a period of rapid consolidation during the last decade of the 20th century. Almost all United States publishers are now owned by foreign conglomerates that have a vast presence in the information business. The consequences of this change and consolidation of ownership has had far-reaching effects; some are already known, but some are certainly unknown at this time. In looking at the phenomenon, this article tries to give some historical perspective on legal publishing, examines the conglomerates as businesses (a “top down” approach), considers important legislation concerning databases, and wonders at the effects all this concentrated change may have on law libraries and the patrons they serve.     

An Inorganic Magnesium-based Consolidant for the Consolidation of Silica Sand (A Substitute for Weathered Sandstone): A Preliminary Exploration

ABSTRACT

Sandstone is a common sedimentary rock that is easily carved due to its weakly cemented fine grains and relatively low strength. Therefore, numerous large-scale grottoes in China are made of sandstone. However, these sandstone cultural heritage structures are often seriously damaged due to temperature and humidity changes, air pollution, biodeterioration, and repeated dissolution and crystallization of soluble salts. In general, it is imperative that a consolidant capable of providing cohesion by infilling pores between the stone grains is synthesized. In recent years, it has been reported that using organic consolidation materials for sandstone protection comes with various negative effects, such as a short lifetime, poor compatibility, and preservation damage. Using inorganic consolidation materials to protect sandstone seems to be one of the research trends for the future. Herein, this paper introduces a permeable, inorganic magnesium-based material (MMH solution) for silica sand consolidation. To assess this consolidant, the paper investigates the influence of varying molar ratios of MgO:MgCl₂·6H₂O:H₂O on properties such as penetration depth, consolidation weight, colour variation, and compressive strength. The results demonstrate that the molar ratios of MgO:MgCl₂·6H₂O:H₂O can significantly affect the consolidation performance. Additionally, it is believed that the MMH solution of MgO:MgCl₂·6H₂O:H₂O?=?5:1:16 can be successfully used for the consolidation of silica sand, as the cubic specimens’ surface micrographs show good compatibility between the consolidation product and sand grains. Experiments (i.e. weight loss rate and mineralogical compositions analysis) are performed to evaluate the cubic specimens’ water resistance properties after being immersed in water. Furthermore, the consolidation material’s failure mechanism as a self-sacrificing material is preliminarily analyzed. Results indicate that MMH solution is a promising conservation material that shows great potential for consolidating severely weathered sandstone.     

Ethyl Silicate for Unbaked Earth Tablets Conservation: Evaluation of the Physico-mechanical Aspects

ABSTRACT

Preservation of cuneiform tablets made with clay minerals is an ongoing conservation issue. A treatment based on TEOS consolidation has been used since 1996 at the Louvre museum. The characterization of the tablets pointed out kaolinite, illite, and smectite as the three main clay minerals constituting the objects. In this research, the physico-mechanical aspects of the treatment are investigated. The penetration depth of the TEOS solution and the gradient induced are quantified using laboratory samples. TEOS treatment preserves the macroscopic swelling and the vapour transfer properties, but modifies the clay’s affinity to moisture. Elastic properties are gradually improved for all clays, but only kaolinite’s strength increases significantly. The impact of TEOS treatment on the natural behaviour related to the respective structure of the clays is considered, and the amount of kaolinite required to create adequate reactions appears to be of interest for conservation treatments.     

Stone reinforcement by calcite crystal precipitation induced by organic matrix macromolecules

Abstract

The weathering of stone monuments results in the leaching of calcite, with a consequent increase in porosity and decrease in integrity. A new method of consolidation uses organic matrix macromolecules extracted from Mytilus californianus shells to induce the precipitation of calcium carbonate within the pores of the stone. The procedure has been tested in the laboratory on samples of bioclastic limestone and dolostone, by measuring changes in total porosity, amount of water absorbed and superficial cohesion. The results appear to confirm the success of the treatment.     

THE CONSERVATION OF PYRITIC STONE ANTIQUITIES

Abstract

The occurrence and identification of ‘fossil disease’ in stone artifacts is described, together with details of techniques for the stabilization and consolidation of the specimens.     

A SIMPLE METHOD FOR THE IDENTIFICATION OF INDIGO

Abstract

Before commencing the conservation treatment of a fifteenth-century coffered ceiling in the convent of Santa Fe, Toledo, the painting materials were analyzed. Elemental analysis of the pigments was carried out by XRF spectrometry. Cross-sections were made of the samples for optical microscopy. The binding media and the varnish were identified by gas chromatography, by analyzing the fatty acids, terpenes and amino acids. Once the painting had been studied, consolidation treatment was applied using different materials according to the solubility of the paint layers. Animal glue was mainly used, and Paraloid B-72 to a lesser extent, as a preliminary to the structural reinforcement of the support.     

Marine Aerosol Weathering of Mediterranean Calcarenite Stone: Durability of Ethyl Silicate,Nano Ca(OH)2, Nano SiO2, and Nanostructured Consolidating Products

ABSTRACT

Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol–gel, Ca(OH)₂, and SiO₂ nanoparticles. These were subjected to marine aerosol accelerated aging cycles and studied by several non-destructive tests and techniques to assess the stability of the products. Results show that weathering caused by salt crystallization is not inhibited but it is slowed down due to the enhancement of superficial mechanical properties (surface cohesion and micro-hardness) achieved after one month of treatments application. A high or low relative humidity of the consolidation environment significantly affects the final mechanical and aesthetical physical properties and therefore conditions the durability of the treated substrates, even producing higher damage than observed in the blank specimens, depending on the product.     

Fabrication of an Ultrasonic Nebulizer: Rate of Flow and Performance Studies

ABSTRACT

This article describes how to build, in-house, a new type of ultrasonic nebulizer and presents the results of tests to determine its rate of aqueous flow and its performance during the transport of a collagen-based adhesive (ratio of adhesive actually delivered to adhesive misted). It also reports on a consolidation treatment case study carried out with the new ultrasonic misting prototype: the NebulA-MG 14. This case study was applied to powdery paint layers of a medium-sized oil painting on canvas, 111.5?×?86.5?cm. The new device is shown to be both reliable and effective, particularly for consolidating medium and large-sized works.     

Approach to the conservation of a mexican saddle and anquera

Abstract

This paper deals with the approach to the conservation of a Spanish-style saddle and anquera (rump cover) from Mexico City and Puebla, Mexico, respectively. The objects were originally bought by an English explorer for a journey and are described in his book. The saddle and anquera are made from vegetable-tanned cowhide with punched and embroidered decoration and metal fittings. The condition, of the leather was assessed scientifically. It exhibits a number of conservation problems, notably surface deterioration and detachment of several sections due to acid attack. Previous conservation treatments have caused the leather to become overstuffed with dressing, resulting in a weakening of the substrate. The conservation ofthe saddle will involve four main stages: removal of excess dressing, stabilization of the leather, consolidation of the friable surface and repair of torn and broken areas. The suitability of various stabilizing agents, consolidants and methods of application was evaluated using mechanical tests alone and accelerated aging and mechanical tests. Naturall y aged and degraded leather was used as an experimental substrate. The results were used to formulate the approach to the conservation of the saddle and anquera.     

Some conservation problems encountered with turmeric on ethnographic objects

Abstract

The pH dependency of turmeric, used as a dye or pigment on ethnographic objects from the Santa Cruz Islands, can present a conservation problem. Great care must be taken with the cleaning, consolidation, repair, storage and display of objects of this nature. A section on the analysis of suspected turmeric is included.     

Conservation of Australian Aboriginal Bark Paintings

Abstract

This work combines our observation that the details of marble statues that have already been lost from the calcite surface are preserved in the gypsum layer, with our research on the mechanism of marble sulfation, to lead to a consolidation of the gypsum, transforming it back to calcium carbonate (calcite) using carbonate ions in solution. Our research shows the mechanism of the conversion of gypsum to calcite, the rate determining steps being the desorption and diffusion of CO^2?₃ We found that the reproduction of the surface detail and the improvement of the mechanical properties was very satisfactory.     

THE CONSERVATION OF A PRESERVED HUMAN HEAD

Abstract

Large ethnographical collections sometimes contain examples of preserved human heads. There are those from the Maori of New Zealand, the well-known Jivaro Indian shrunken heads, and others from Papua-New Guinea. The article describes the preservation process as practised in Western Papua by the tribal craftsman, and then the problems of conservation in the museum laboratory. The latter include the cleaning of the skin, and the painted areas of the face, with the non-ionic surface-active agent Lissapol N in distilled water, followed by consolidation of the painted surface with an application of 2 % soluble nylon in industrial methylated spirit. Clay and fibre within the head were consolidated with a 5 % solution of the polymethacrylic ester Bedacryl 122X (I.C.I.) in xylene; and the fibre ear ornaments, after cleaning with Lissapol N, were consolidated with a 5 % solution of soluble nylon in industrial methylated spirit. The specimen was fitted with a specially made polythene cover, and stored in an individual box.     

Main Issues in Cataloging Persian Language Materials in North America

ABSTRACT

The main problems of cataloging Persian language materials as it is practiced in North America are discussed. The problems are grouped by origin: those that originate from the implementation of the ALA-LC Romanization Tables for Persian; those that occur either because of misleading examples used in that Table's rules for application section, or a lack of functional knowledge of Persian; and those that appear in the treatment of names generally and choice and form of main entry specifically, due to the application of inappropriate rules for Persian names. Suggestions for dealing with these cataloging issues are presented.     

Relining with Glass-Fiber Fabric

Abstract

Thermoplastic resins such as Butvar B98 and Acryloid B72 used as consolidants in solution may retain solvents which lower the glass transition temperature and plasticize the polymer. These effect scan be minimized by using solvents with low boiling points. This study is part of a continuing effort to examine consolidation of deteriorated wood in a systematic manner.     

The CONSER/PCC Evolution

ABSTRACT

In October 1997, the CONSER Program will join the Program for Cooperative Cataloging (PCC). Hirons and Schottlaender discuss the developments that led up to the consolidation, the new vision for the combined program as expressed in a set of principles, and the benefits to each program. They also examine the potential for change in CONSER and PCC inherent in the acceptance of the principles.