Materials for Conservation. Organic Consolidants, Adhesives and Coatings

285 Pages·1987·5.99 MB·English

by  C.V Horie (Auth.)

Butterworths Series in Conservation and Museology
Series Editors : Arts and A rchaeology
Stephen G Rees- Jones
Courtauld Institute of Art, University of London
Architecture
Derek Linstrum
Institute of Advanced Architectural Studies, University of
York
US Executive Editor: Norbert S Baer,
New York University, Conservation Center of the Institute
of Fine Arts
Consultants: Sir Bernard Feilden
David Bomford
National Gallery, London
C V Horie
Manchester Museum, University of Manchester
Published titles: Artists' Pigments c. 1600-1835, 2nd Edition (Harley)
Conservation and Exhibitions (Stolow)
Conservation and Restoration of Works of Art and
Antiquities (Kühn)
Conservation of Building and Decorative Stone (Ashurst,
Dimes)
Conservation of Glass (Newton, Davison)
Conservation of Historic Buildings (Feilden)
Conservation of Library and Archive Materials and the
Graphic Arts (Petherbridge)
Conservation of Manuscripts and Paintings of South-East
Asia (Agrawal)
Conservation of Marine Archaeological Objects (Pearson)
Conservation of Wall Paintings (Mora, Mora, Philippot)
The Museum Environment, 2nd Edition (Thomson)
The Organic Chemistry of Museum Objects (Mills, White)
The Textile Conservator's Manual (Landi)
Related titles: Manual of Curatorship
Materials for Conservation
Museum Documentation Systems
Materials for Conservation
Organic consolidants, adhesives and coatings
C.V. Horie
Keeper of Conservation
The Manchester Museum
Butterworths
London Boston Singapore Sydney Toronto Wellington
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First published 1987
Reprinted 1990 (with corrections)
© Butterworth & Co (Publishers) Ltd, 1987
British Library Cataloguing in Publication Data
Horie, C. V.
Materials for conservation: organic
consolidants, adhesives and coatings. —
(Butterworths series in conservation and museology).
1. Art objects — Conservation and restoration
2. Museum conservation methods
I. Title
069.5'3 N8560
ISBN 0-408-01531-4
Library of Congress Cataloging inP ublication Data
Horie, C. V. (Charles Velson)
Materials for conservation.
(Butterworths series in conservation and museology)
Bibliography: p.
Includes index.
1. Coatings. 2. Adhesives. 3. Art—Conservation 1
and restoration. I. Title II. Series.
TP156.C57H67 1987 667'.9 87-13830
ISBN 0-408-01531-4
Composition by Genesis Typesetting, Laser Quay, Rochester, Kent
Printed and bound by Hartnolls Ltd, Bodmin, Cornwall
Preface
The conservation of historic materials requires the application of a
wide range of knowledge and skills. The aim of this book is to
provide background information on one aspect of conservation
treatments: the properties of organic consolidants, adhesives and
coatings as they affect the treatment of objects. The variety of
film-forming and binding materials, together with associated
materials such as oils, is not covered by a single descriptive term.
The inadequate word 'polymer' or 'resin' will often be used to
encompass these materials. The vast number of commercial
polymers and formulations creates considerable scope for harmful
as well as beneficial changes in the practice and philosophy of
conservation. Polymer science has increased our insight into
polymer properties, offering the potential for valuable improve-
ments in treatments and the materials used. It is my hope that the
reader will assess the use of both new and old materials on objects
more rigorously.
This review comes at the end of an era in conservation practice.
In the past, materials were applied in a traditional manner,
frequently with no evaluation of the merits or consequences of the
addition. When new, synthetic materials were introduced com-
mercially, these were used in the same role, often without much
evaluation because they appeared to be better. Testing of the
industrial products was later carried out, sometimes thoroughly, in
order to rank them in suitability for particular roles. This is the
phase of development which I hope is passing. In its place,
treatments are being developed, incorporating materials with
appropriately specified properties, designed to fulfil a defined
conservation need.
Conservators must know about the added material and its
effects on objects before making a decision on whether, and how
best, to incorporate a material into a treatment for the object. Part
I outlines the properties of polymers that are important in the
interaction of polymers with objects. Chapters 1 and 5 provide a
qualitative introduction and summary of the scientific basis for
V
vi Preface
defining and assessing those properties which are covered in the
intervening chapters. Part II provides a detailed consideration of
individual polymers, their properties and uses in conservation.
Most polymer types that have been used in the conservation of
objects are included. At the end of the book are appendices which
summarize data referred to in the text.
There are various introductory texts in this field for conservators
(Crafts Council, 1983; Feller et ai, 1971; Anon, 1968). Many
books are available for schools and the general public which
outline the concepts and properties of polymers. More detailed
reference books which assume some knowledge of chemistry
include Brydson (1982), Roff and Scott (1971) and Mark et al
(1964ff). The reader is assumed to have access to publications of
the International Institute for Conservation. Polymers that have
been adequately described in those publications have been given a
slighter treatment here to avoid duplication.
Conclusions
1. The interactions between objects and polymers, etc. are
ill-understood. Assuming that the object is the primary concern
of the conservator, consolidants, adhesives and coatings should
be applied only when necessary to the survival of the object.
They should not be used as an alternative to proper packaging,
environmental control, etc. Given the difficulties of removing
polymers, they should be applied sparingly.
2. One of the most difficult tasks of a conservator is reversing the
conservation treatment of an object before starting new
stabilization treatments, etc. Publication of past treatments,
assessments of their effects and reversal methods is rare but
most welcome to the conservator who must treat objects with
comparable problems. Conservation is dependent on the
material history that survives. The history of conservation,
which is rarely written, is an integral part of conservation
studies.
3. Most commercial polymers are produced for industrial
applications that are ephemeral by conservation standards.
Conservators both past and present have used products whose
suitability is untested. A few new products specified and tested
for conservation are coming on to the market, but their
composition remains proprietary. These must be viewed with
the suspicion held for any commercial material. There is
Preface vii
sufficient information available to enable formulations to be
developed to conservation standards and revealed in the public
domain. These recipes would reduce the need for commercial
products of unknown composition and variability.
Acknowledgements
The impetus for the writing of this book was given to me by
Professor R. G. Newton and I wish to thank him and Mrs J.
Newton for their support in the early stages of its formation. The
need for a conservation text on polymers, etc. has been made clear
to me by students of conservation at various institutions who, by
their interest and questions during lecture courses, have prompted
me to look more closely at the problems of objects and the
treatment of them. Miss L. Bacon, Professor S. Rees-Joncs, my
wife (Dr D. Kenyon) and Professor W. J. Feast have kindly read
through portions of the text and suggested valuable improvements
both in style and content.
The data on individual products has been collated from
information supplied by their manufacturers. The ready supply of
data sheets and samples of the products from all the manufacturers
listed in Appendix 5 enabled the compilation of the tables and, in
some cases, the evaluation of properties important for conserva-
tion. I was pleasantly surprised by how many manufacturers
provided advice and unpublished data on their products, so
increasing insight into their application for conservation.
I wish to thank the following for advice and data which helped to
clarify specific points or wider issues: Dr R. L. Feller, Dr S. G.
Croll, Mr G. Berger, Dr E. P. Mel'nikova, Professor Dr K.
Ueberreiter, Dr J. Winter, Professor W. C. Wake, Professor J. D.
Ferry and Dr N. Tennent.
Preface vii
sufficient information available to enable formulations to be
developed to conservation standards and revealed in the public
domain. These recipes would reduce the need for commercial
products of unknown composition and variability.
Acknowledgements
The impetus for the writing of this book was given to me by
Professor R. G. Newton and I wish to thank him and Mrs J.
Newton for their support in the early stages of its formation. The
need for a conservation text on polymers, etc. has been made clear
to me by students of conservation at various institutions who, by
their interest and questions during lecture courses, have prompted
me to look more closely at the problems of objects and the
treatment of them. Miss L. Bacon, Professor S. Rees-Joncs, my
wife (Dr D. Kenyon) and Professor W. J. Feast have kindly read
through portions of the text and suggested valuable improvements
both in style and content.
The data on individual products has been collated from
information supplied by their manufacturers. The ready supply of
data sheets and samples of the products from all the manufacturers
listed in Appendix 5 enabled the compilation of the tables and, in
some cases, the evaluation of properties important for conserva-
tion. I was pleasantly surprised by how many manufacturers
provided advice and unpublished data on their products, so
increasing insight into their application for conservation.
I wish to thank the following for advice and data which helped to
clarify specific points or wider issues: Dr R. L. Feller, Dr S. G.
Croll, Mr G. Berger, Dr E. P. Mel'nikova, Professor Dr K.
Ueberreiter, Dr J. Winter, Professor W. C. Wake, Professor J. D.
Ferry and Dr N. Tennent.
To my father
Many of the materials mentioned in this book are hazardous to the
operator or other people and property. Although some hazard
information has been provided, the responsibility for ensuring the
completeness or accuracy of the appropriate hazard information is
the responsibility of the person undertaking the process.
The mention of a material or process does not constitute a
recommendation for its use on objects - usually the reverse.
The author and publisher accept no responsibility for the
consequences of the application of information or opinion
expressed in this book.
1 Introduction
1.1 Use of resins in conservation
Resins are used for many purposes in the conservation of objects:
Consolidants
Adhesives
Coatings
Moulding
Casting
Support stands
Display and storage materials.
This list is ranked according to the intimacy of contact with the
object. The closer the contact, the more likely the object is to be
affected by the polymer properties. In the first four categories the
resin is applied to the object rather than the other way around.
These are therefore of greater concern.
In conservation it is an important discipline to study an object
before one works on it. One should:
(a) Find out what is wrong with the object.
(b) Discover the cause of the defect.
(c) Decide on the type of action.
(d) Choose the appropriate method and materials.
Neither (a) nor (b) are discussed in this work, but both (c) and (d)
are determined by the potential and limitations of the available
materials. The possible roles that the resin will play in the
conserved object must be examined closely. Resins frequently
serve two purposes at once. When sticking friable pottery, the
adhesive may also consolidate and strengthen the edges. When
coating loose paint, the varnish will both cover the paint flakes and
stick them to the substrate. These dual roles may be of great
importance when the time comes to reverse the treatment.
Now the role(s) of the material have been stated, the required
properties may be specified. In the real world one can never satisfy
3