Metals conservation

The bronze apoxyomenos, ,dated between 1st and 2nd century BC,found and recovered from Adriatic sea near small island Vele Oryule,near island Loshiny, example of archaeological metals conservation, Croatia

Metals conservation, or more precisely conservation-restoration of metals is the activity devoted to the protection and preservation of historical (religious, artistic, technical and ethnographic) and archaeological objects made partly or entirely of metal. In it are included all activities aimed at preventing or slowing deterioration of items, as well as improving accessibility and readability of them as objects of cultural heritage. Despite the fact that metals are generally considered as the relatively permanent and stable materials, in contact with the environment they deteriorate gradually, some faster and some much slower. This applies especially to archaeological finds.

It is very important that a conservator of metals has knowledge of basic metalworking techniques,history of metalwork, history of art, archaeology, corrosion of metals, scientific research methods, theory and ethics of conservation-restoration.

Metals and alloys commonly used for cultural heritage objects

• Gold
• Silver
• Copper
• Bronze
• Brass
• Nickel
• Nickel silver
• Monel
• Chromium
• Iron and Steel
• Weathering steel(Corten)
• Stainless steel
• Titanium
• Tin and Pewter
• Lead
• Zinc
• Aluminium

Metals and alloys less commonly used for cultural heritage objects

• Antimony
• Magnesium
• Niobium
• Palladium
• Platinum
• Rhodium
• Mercury
• Electrum
• Tumbaga
• Shakudo
• Shibuichi
• Bidri
• Hepatizon

Basic metalworking techniques

Basic techniques

• Casting
• Forging
• Folding
• Sawing
• Cutting
• Bending
• Drilling
• Filing
• Piercing
• Sanding
• Polishing

Joining techniques

• Soldering
• Welding
• Mechanical joining
• Gluing/cementing

Some supplementary techniques

• Repousse
• Chasing
• Raising
• Metal spinning
• Annealing

Surface decoration techniques

• Enamelling
• Niello
• Engraving
• Etching
• Granulation
• Filigree
• Inlay(Damascening)
• Mokume gane
• Pattern welding
• Plating
• Chemical coloring of metals(Patination´)
• Heat coloring
• Combining metals and other materials

Some contemporary techniques

• Electroforming
• Reticulation
• Anodizing
• Photoetching

Deterioration of metals

An essential cause of deterioration is corrosion of metal objects or object deterioration by interaction with the environment. As the most influential factors of deterioration of historical objects should be pointed out as the relative humidity and air pollution while in archaeological objects a crucial role has composition, depth, humidity and amount of gasses in the soil. In cases of marine or fresh water finds the most important factors of decay are the amount and composition of soluble salts, water depth, amount of dissolved gases, the direction of water currents and the role of both microscopic and macroscopic living organisms.

Deterioration of materials associated with metals

Associated materials deteriorate depending on the origin whether they are organic or inorganic materials. Organic materials usually fail in a relatively short period of time, primarily due to biodegradation.With inorganic materials are these processes considerably longer and more complex.Amount of gases,humidity,depth and composition of soil are very important . In case of salty and sweet water finds essential are amount of gases dissolved in water,depth of water,direction of currents ,and microscopic and macroscopic living organisms.

Organic materials

• Leather
• Wood
• Paper
• Fur
• Feathers
• Textile
• Bone
• Horn
• Tortoiseshell
• Amber
• Plant fiber
• Shell
• Pearls
• Ivory
• Coral
• Jet (lignite)

Inorganic materials

• Precious and semiprecious stones(Gemstone)
• Glass
• Enamel
• Niello
• Ceramics
• Porcelain
• Plastics

Metals conservation planning

Basics

As with the conservation and restoration works on any other material, here are the basic tenets of conservation-restoration based on the quality of execution and the best possible preservation of cultural , historical and technological identity and integrity of objects. Minimal intervention , reversibility and repeatability of preferred treatment are essential, as well as the possibility of easy identification of restored parts. Recently non-toxic nature of used materials and procedures becomes important too, both in relation to objects and conservator-restorer as a performer,but also in relation to the environment.

Research

Nowadays scientific research is an integral part of the metals conservation treatment ,at least in highly developed countries.

Identification of metals and alloys

• Simple methods - visual examination,spot tests,specific gravity
• Scientific methods - XRF, XRD, Particle-induced X-ray emission, LIBS, SEM, electrochemical techniques, metallography

Identification of corrosion processes and products

• Simple method - visual examination,spot tests
• The Oddy test - for copper, silver, and lead
• Scientific methods - xrd, SEM, metallography

Identification of materials associated with metals

• Simple methods - visual examination,spot tests,specific gravity
• Scientific methods - xrf, chromatography

Identification of technology used to produce objects

• Simple methods - visual examination
• Scientific mehods - metallography, x-ray radiography, x-ray computed tomography

Decision making

In preparing the strategy of the metals conservation project interdisciplinary approach to the same is essential.It implies the participation of as many experts as is possible , as a minimum, we can take curator (archaeologist, historian, art historian), scientists specialized for corrosion of metallic objects of cultural heritage and the conservator - restorer.

Documentation

Systematic and well-managed documentation is today an essential prerequisite for quality executed conservation and restoration treatments , including documentation of the state of objects before, during and after treatment. Identification of materials and procedures used to produce object and the results of any scientific research must be part of documentation too.Last but not least- an integral part of the documentation must be a recommendation for further care of object.

Ethics and ethical problems in metals conservation

The ethical concept of conservation of metal objects in principle is the same as those in other fields of conservation-restoration of cultural heritage.

But there are several specific problems that can only be found in the conservation of metals - problem of heat treatment of archaeological objects, and the problem of radical restoration of historic, mostly technical, but also architectonic objects too.

While in the first case problem is primarily in the destruction of valuable scientific data, in case of the technical, the architectural, and somewhat less often, historical objects problem is that a radically restored items just simulate the original appearance of the object, and so in some ways that objects can be considered even as ,more or less successfull fakes, which only superficialy simulate long-lost or never existing state of object.

According to the above-mentioned ,whenever it is possible real historical substance must be preserved.Thoroughly documented and technically professionally executed restoration of objects,must be avoided because such objects must be seen only as freshly painted surrogates of authentic historic substance.

Ethical problems connected with conservation of sacred metallic heritage objects objects can be included too^[1]

Conservation

Preventive Conservation

Metallic heritage objects are sensitive to environmental conditions such as temperature, humidity ,air pollution and exposure to light and ultraviolet light. They must be protected in a controlled environment where such variables are maintained within a range of damage-limiting levels.

Preventive conservation is an important element of museum policy and collections care. It is an essential responsibility of members of the museum profession to create and maintain a protective environment for the collections in their care, whether in store, on display, or in transit. A museum should carefully monitor the condition of collections to determine when an artifact requires conservation work and the services of a qualified conservator.

Interventive conservation

Cleaning

The simplest and most common procedure(but it can be very complex too) . We distinguish between mechanical, chemical, electrochemical, ultrasonic and laser cleaning. In principle, aimed at removing of dirt and corrosion products.

• Mechanical cleaning and removal of corrosion products
• Chemical cleaning and removal of corrosion products
• Electrochemical cleaning and removal of corrosion products
• Ultrasonic cleaning and removal of corrosion products
• Laser cleaning and removal of corrosion products

Structural consolidation

Aimed at strengthening of the physical structure of the object, and correcting the shape of the object.

• Mechanical joining - riveting / tab and slot / overlaping / screws
• Soldering - soft / hard
• Welding - oxyacetilene / electric arc / TIG / tack / laser
• Gluing/Cementing

Reconstruction of missing parts or surface decoration

In certain cases, metals conservator must re-create the lost parts of objects or restore original surface decoration . This approach is accurate only if we have an exact documentation or photographs of items in a complete, currently non-existent state that we want to return.

New parts must be clearly and visibly marked and at least they must be minimally different from the original historic material.

If needed, those parts must be easily and completely removable from the object, and with methods which will not harm it.

Stabilization

Focused on slowing of deterioration of objects - in case of archaeology objects the thorough removal or blocking of chloride salts.In case of the historical objects it is focused on the use of corrosion inhibitors ,conversion coatings ,rust converters or eventually oxygen free storage.

• Chloride removal
• Corrosion inhibitors
• Rust converters
• Conversion coatings
• Oxygen free storage

Protective Coatings

Still mainly focused on use of clearcoats and waxes,in case of technology objects oil coatings can be used too. In general it supports the stabilization process.

• Clearcoats - Paraloid B 72 / Paraloid B 67 / Paraloid B 44 /Paraloid B 48 N / Incralac / ORMOCER
• Waxes - Renaissance Wax/Cosmolloid 80 H / Dinitrol 4010
• Oils - WD 40 / Ballistol / 80 parts white spirit+20 parts fish oil
• Combinations - base coat Paraloid B 72 / topcoat Renaissance Wax etc.

Storage of metallic heritage objects

The items should be stored in rooms that are protected from polluted air, dust, ultraviolet radiation, and excessive relative humidity - ideal values are temperature of 16-20 °C and up to 40%(35-55% according to recent Canadian Conservation Institute recommendations) relative humidity, noting that if metal is combined with organic materials, relative humidity should not be below 45%. Archaeological objects must be stored in rooms (or plastic boxes)with very low relative humidity, or in the case of particularly valuable items in the chambers with nitrogen or argon. Objects with active corrosion of copper or copper alloys up to 35% RH. Iron objects with active corrosion 12-15% RH. Shelves in the storerooms must be of stainless steel or chlorine and acetate free plastic or powder coated steel. Wood and wood based products(Particle board, plywood) must be avoided. Also do not use rubber, felt or wool .When you are handling metal objects,always wear clean cotton gloves . Lighting levels must be kept below 300 lux (up to 150 lux in case of lacquered or painted objects,up to 50 lux in case of objects with light sensitive materials)^[2]

History of metals conservation

Important persons

• Georg Rosenberg
• William Matthew Flinders Petrie
• Friedrich Rathgen
• Alexander Scott
• Harold Plenderleith
• Mstislav Vladimirovich Farmakovskiy
• Albert France-Lanord
• Hanna Jedrzejewska

Specializations within the profession

• Conservation of Historical Metal Objects
• Conservation of Archaeological Metal Objects
• Conservation of Technological Metal Objects
• Conservation of Etnographic Metal Objects
• Conservation of Architectural Metal Objects
• Conservation of Metal Sculpture
• Conservation of Gold and Silversmiths Works

Training

USA

• Bufallo State College,Art Conservation Department,objects specialization
• UCLA/Getty Masters Program - Conservation of Archaeological and Etnographic Materials
• Winterthur/University of Delaware Program in Art Conservation, objects specialization

Canada

• Queens University,Art Conservation,objects specialization
• Fleming College, Collections Conservation and Management

South America

• Chile

Centro Nacional de Conservacion y Restauracion,Santiago de Chile,objetos arqueológicos, etnográficos e históricos

Australia

The University of Melbourne,Centre for Cultural Materials Conservation

Europe

• Austria

Universitaet fuer Angewandte Kunst,Wien,Konservierung/Restaurierung von Objekten

• Belgium

Koninklijke Academie voor schone kunsten,Antwerpen,metalen conservatie

• Croatia

Sveučilište u Dubrovniku,konzervacija restauracija metala(BA+MA)

• France

• Germany

1. Roemisch Germanisches Zentralmuseum,Mainz,Ausbildung zum Restaurator des Fachbereischs Archeologie
2. Hochschule fuer Technik und Wirtschaft,Berlin, schwerpunkt Archaeologisch-Historisches Kulturgut
3. Staatlische Akademie der Bildende Kuenste,Stuttgart,Objekt Restaurierung
4. Fachhochschule Potsdam,Metallkonservierung

• Hungary

Hungarian Academy of Fine Arts,Budapest,conservation of metalwork and goldsmiths works

• Italy

Instituto Centrale per il Restauro,Roma

• Netherlands

Instituut Collectie Nederland,Amsterdam,metallrestauratie

• Poland

Nicolaus Copernicus University in Torun, Institute of Fine Art, Department of Conservation and Restoration of Historic and Artistic Works, graduate program , metal conservation

• United Kingdom

1. West Dean College,metalwork conservation
2. University of Sussex,metalwork conservation

• Switzerland

La Chaux de Fonds,Haute Ecole de Conservation-restauration Arc,objects conservation

Russian Federation

• Akademiya Imeni S.G.Stroganova,Moscow-katedra"Restavraciya hudozhestvennogo metalla"(Conservation of artistic metalwork)

Further reading

1.Corrosion and metal artifacts : a dialogue between conservators and archaeologists and corrosion scientists,Washington 1977.

2.Conservation & restoration of metals : proceedings of the symposium held in Edinburgh, 30-31 March, 1979.,Edinburgh 1979.

3.Stambolov, T. The corrosion and conservation of metallic antiquities and works of art - a preliminary survey ,Amsterdam 1985.

4.Townsend,J.H.;Child,R.E. Modern metals in museums,Cardiff 1988.

5.METAL 95,Proceedings of International Conference on Metal Conservation,London 1997.

6.METAL 98,Proceedings of International Conference on Metal Conservation,London 1999.

7.METAL 01,Proceedings of International Conference on Metal Conservation,Perth 2002.

8.METAL 04,Proceedings of International Conference on Metal Conservation,Canberra 2005.

9.METAL 07,Proceedings of International Conference on Metal Conservation,Amsterdam 2007.

10.METAL 2010.,Proceedings of International Conference on Metal Conservation,Charleston 2011.

11.Scott,D.A. Metallography and Microstructure of Ancient and Historic Metals,Santa Monica 1991.

12.Scott,D.A. Ancient and Historic Metals-Conservation and Scientific Research,Santa Monica 1994.

13.Scott,D.A. Copper and Bronze in Art-Corrosion,Colorants,Conservation,Los Angeles 2002.

14.Scott,D.A. Iron and Steel in Art-Corrosion,Colorants,Conservation,London 2009.

15.Selwyn,L. Metals and Corrosion-A Handbook for Conservation Professional,Ottawa 2004.

16.Draymann-Weiser,T. Gilded Metals-History,Technology,Conservation,London 2000.

17.Dillman,P.;Beranger,G.;Piccardo,P.;Matthiesen,H. Corrosion of metallic heritage artefacts-Investigation,Conservation and Prediction of long term behaviour,Cambridge 2007.

18.Cronyn,J.M. The Elements of Archaeological Conservation,London 1990.

19. Rodgers,B. The Archaeologist Manual for Conservation-A Guide to Non- toxic,Minimal Intervention Artifact Stabilization,New York 2004.

20.Stuart,B. Analytical Techniques in Materials Conservation,Chichester 2007.

21.May,E.;Jones,M. Conservation Science-Heritage Materials,Cambridge 2006.

22.Untracht,O. Metal Techniques for Craftsmen,New York 1968.

23.La Niece,S.;Craddock,P. Metal Plating and Patination: Cultural,Technical and Historical Develpoments,Boston 1993.

24.Horie,C.V. Materials for Conservation,Oxford 2010.

25.Smith,R.D. Make all sure : the conservation and restoration of arms and armour,Leeds 2006.

26.Appelbaum,B. Conservation Treatment Methodology,New York 2007.

Some important books on Metal conservation in languages other than english

1.Heinrich,P.(Hrsg.) Metallrestaurierung,Muenchen 1994.

2.Stambolov,T.;Bleck,R.D.;Eichelmann,N. Korrosion und Konservierung von Kunst und Kulturgut aus Metall,Weimar I/1987.,II/1988.

3.Mourey, W. La conservation des antiquités métalliques, du chantier de fouilles au musée, Draguignan 1987.

4.Volfovsky,C.;Philippon,J. La Conservation des metaux,Paris 2001.

5.Marabelli,M. Conservazione e restauro dei metalli d`arte,Rome 1995.

6.Schemahanskaya,M.S. Restavraciya metalla,Moscow 1989..(online)

7.Minzhulin,O.I. Restavraciya tvoriv z metalu,Kiev 1998.

8.Catello,D Il restauro delle opere in argento.Restoration of silver artifacts,Napoli 2008.

9.Meissner,B.;Doktor,A.;Mach,M. Bronze ud Galvanoplastik-Geschichte-Materialanalyse-Restaurierung,Dresden 2000.(online)

10.Mach,M. Metallrestaurierung/Metal Restoration,Muenchen 1997.

11.Krist,G. Metallrestaurierung-Metallkonservierung:Geschichte,Methode und Praxis,Wien 2009.

12.Schmidt-Ott,K. Das Plasma in der Metallkonservierung-Moeglichkeiten und Grenzen,Zurich 2010.

13.Anheuser,K. Im Feuer Vergoldet,AdR-Schriftenreihe zur Restaurierung und Grabungstechnik, Band 4 / 1998 .

14.Diaz Martinez,S.;Garcia Alonso,E. Tecnicas metodologicas aplicadas a conservacion-restauracion del patrimonio metalico,Madrid 2011. (online)

15.Barrio Martin,J.;Chamon Frenandez,J. Proyecto Dorados:tecnología, conservación y restauración de los metales dorados medievales,Madrid 2011.

16.La técnica radiográafica en los metales históricos,Madrid 2011. (online)

17.Salvi,A. Meteo e metalli.Conservazione e restauro delle sculture al aperto.Dal Perseo all arte contemporanea,Florence 2007.

18.Bruecke,D.Die Konservierung pigmentierter Altbeschichtungen auf Stahlbauten,Saarbrucken 2011

19.Fischer,A. Reste von organischen Materialien an Bodenfunden aus Metall – Identifizierung und Erhaltung für die archäologische Forschung,Muenchen 1997.

20.Schlaepfer,B.R. Metais:Restauracao e conservacao,Rio de Janeiro 2009.

21.Gaomez Moral,F. Conservacion De Metales De Interes Cultural ,Quito 2004.

22.Krause,J. Sarkofagi cynowe : problematyka technologiczna warsztatowa i konserwatorska ,Torun 1995.

23.Mach,M.;Moetnner,P. Zinkguß, die Konservierung von Denkmälern aus Zink ,Muenchen 1999.

24.Barrandon,J.N.;Meyer-Roudet,H. A la recherche du métal perdu : nouvelles technologies dans la restauration des métaux archéologiques,Paris 1999.

Important older books

1.Rathgen,F. Die Konservierung von Altertumsfunden,Berlin 1898.(chapter on metals conservation).(online)

2.Flinders Petrie,W.M. The Method and Aims in Archaeology,London 1904.(chapter on conservation)(online)

3.Rosenberg,G. Antiquités en fer et en bronze : leur transformation dans la terre contenant de l'acide carbonique et des chlorures et leur conservation ,Copenhagen 1917.

4.Scott, A. The cleaning and restoration of museum exhibits (report upon investigation conducted at the British Museum, Department of Scientific and Industrial Research). London 1921.

5.Scott, A. The cleaning and restoration of museum exhibits, 2d report. British Museum, Department of Scientific and Industrial Research. London 1923.

6. Fink,C.G.;Eldridge,C.H. The restoration of ancient bronzes and other alloys,New York 1925.

7.Galnbek,I.A. Ochistka i sokhranenie metallicheskikh predmetov drevnosti. ,Lenigrad 1925.(first book dedicated to metals conservation/not only bronze and iron/!)

8.Scott, A. The cleaning and restoration of museum exhibits, 3d report. British Museum, Department of Scientific and Industrial Research. London 1926.

9.Nichols, H. W. Restoration of ancient bronzes and cure of malignant patina. Chicago 1930.(online)

10.Lucas, A. Antiques: Their restoration and preservation. London 1932. (online)

11.Plenderleith,H.J. The preservation of Antiquities,London 1934.(Chapter on metals conservation)

12.Ocherki po metodike tehnologicheskog issledovaniya restavracii i konservacii drevnih metalicheskih izdeliy ,Moscow 1935.

13.Farmakovskiy,M.V. Konservaciya i restavraciya muzeinih kollekciy ,Moscow 1946.(chapter on metals conservation)(online)

14.Plenderleith,H.J. The Conservation of Antiquities and Works of Art,London 1956.(chapter on metals conservation)

15.France-Lanord,A. La conservation des antiquites metalliques,Paris 1962.

Free software that can be used in metals conservation

1.The Use of Expert Systems in Conservation

2.The Modular Cleaning Program

3.Download free conservators documentation software

External links

1.ICOM CC WG Metals

2.BROMEC - Bulletin of Research On Metal Conservation

3.METALConsninfo

4.PROMET project

5.MEDAL project

6.UCLA metals course-archived presentations

7.Society for Historical Archaeology-Conservation FAQ and facts

8.Building Conservation-articles on metals conservation

9.Research Into Protective Coating Systems for Outdoor Bronze Sculpture and Ornamentation(article with links to some other similar articles)

10.R.W.Hoge:Conservation Rules for Coins and Medals

11.A Framework for Conservation of metals

12.Recognizing Metals and their Corrosion Products

13.*Schotte,B.Adriaens,A. Treatments of Corroded Lead Artefacts - An Overview

14.A Simple Guide for Archaeological Materials Characterization

15.International Conference on Strategies for Saving Indoor Metallic Collections,Cairo 2007.-conference papers

16.Russian article on tannin based treatment of "bronze disease"(in russian - Try Google Translator,it is free)

17.Metallography and Microstructure of Ancient and Historic Metals-download free book

18.Ancient and Historic Metals-Conservation and Scientific Research-download free book

19.METAL 2004-proceedings of conference

20.Big Stuff 2004.- conference papers

21.Big Stuff 2007.-conference papers - DEAD LINK

22.CONSIST project

23.Hamilton,D. Methods of Conserving Archaeological Material from Underwater Sites

24.Methodic Recommendations for conservation of metals(in russian!-try Google translator-it is free,translation can be very silly)

25.Native American Jewelry Conservation Project: Part 2

26.Koh,Y.S. Laser Cleaning as a Conservation Technique for Corroded Metal Artifacts,doctoral thesis,Lulea 2006.

27.Siano,S. Laser Ablation in Conservation of Artworks

28.CCI Notes 9/2 Storage of Metals

29.CCI Notes 9/1 Recognizing Active Corrosion

30.CCI Notes 9/4 Basic Care of Coins and Medals

31.Watkinson,D. Preservation of Metallic Cultural Heritage,2010.

32.Boissonnas,V. An introduction to the history of metals conservation

33.Preservapedia - Metals conservation

34.Grissom,C.A. The Conservation of American War Memorials Made of Zinc

35.Bailey,G.T. Stabilization of wrecked and corroded aluminium aircraft

36.CCI Notes 9/3 The Cleaning,Polishing and Protective Waxing of Brass and Copper

37.CCI Silver Care and Tarnish removal

38.CCI Notes 9/8 Mechanical Removal of Rust fom Machined Ferrous Surfaces

39.CCI Notes 9/5 Tannic Acid Treatment

40.Care and Conservation of Pewter

41.Conservation of lead sculpture

42.Conservation of lead and lead alloys

43.Diaz Martinez ,S.;Garcia Alonso,E. Tecnicas metodologicas aplicadas a la conservacion-restauracion del patrimonio metalico,Madrid 2011.

44.Watkinson,D. Conserving cultural material : Ethical challenges for the conservator

45.Mach,M.;Doktor,A.;Meissner,B. Bronze und Galvanoplastik-Geschichte-Materialanlyse-Restaurierung,Dresden 2001.

46.Minimum Common Standards Definition – Model Curricula Metals -EQF Level 7 - ECPL

47.Laboratorie d archeologie des metaux,Nancy

48.The TIGHAR Guide to Aviation Historic Preservation Terminology

49.Hayha,H.THE HISTORY OF IRON PROTECTION. DESCRIPTION OF MATERIALS AND EVALUATION OF THEIR PROPERTIES

50.La técnica radiográafica en los metales históricos(english translation included),Madrid 2011.

51. National Research Laboratory for Conservation of Cultural Property,Lucknow,India-research papers,some good articles on metals conservation

52.Regis Bertholon: La limite de la surface d origine des objets metalliques archeologiques - doctoral thesis

53.Castillo Narrea, L.E.J.A. Conservacion y Restauracion de algunos objetos arqueologicos:Arte,Tecnica y Metalurgia,Santiago de Chile 2008. - thesis

54.L.B.Brostoff:Coating Strategies for the Protection of Outdoor Bronze Art and Ornamentation (thesis)

55.Care and Handling of Bronze Objects

56.Wanhill,R.J.H. Brittle archaeological silver- identification,restoration and conservation

57.Strandberg,H. Perspectives on Bronze Sculpture Conservation. Modelling Copper and Bronze Corrosion,thesis

58.Conservation of iron and steelwork in historic structures and machinery/Maintenance handbook

Metals conservation video files

1.Conserving Bronze: The Lamp with Erotes from Vani

2.Caring for Metals - Housekeeping for Historic Sites

3.USS Monitor Engine Removed from Water

4.Laser Cleaning of Bronze Eagle in Oak Park

5.Re-Constructing Silver Objects from the Staffordshire Hoard

6.Erik Risser Describes the Conservation of the Apollo Saettante at the Getty Villa

7.CoinScubber - Cleaning Ancient Coins

8.Cleaning an Outdoor Sculpture Part I

9.Parlament Wien, Quadriga, Restaurierung, Bronze

10.Dorure au mercure

11.Repatination of a Bronze WWII Memorial Plaque

12.how to care for bronze sculptures

13.Restoring an Artifact at the SCCRRMM

14.Clemson Conservation Center: H.L. Hunley submarine - Part 1/3

15.NCPTT Iron Fence Repair - Cemetery Monument Conservation

16.Restoration of the USS Monitor

References

1. ^ Thompson,J.C. :On restoring sacred objects http://cool.conservation-us.org/byauth/thompson/sacred/
2. ^ Budija Goran:Čišćenje,zaštita i održavanje umjetničkih predmeta i starina od metala,version december 2010.,Zagreb, http://www.e-insitu.com/images/fbfiles/files/BUDIJA_Ciscenje2.pdf