Metals conservation
Encyclopedia
Preservation
Preservation may refer to:* Heritage preservation:** Historic preservation, of buildings, monuments, etc.** Preservation , of books, recordings, etc.** Conservation , of the natural environment...
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
Cultural heritage
Cultural heritage is the legacy of physical artifacts and intangible attributes of a group or society that are inherited from past generations, maintained in the present and bestowed for the benefit of future generations...
. 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
Knowledge
Knowledge is a familiarity with someone or something unknown, which can include information, facts, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject...
of basic metalworking
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...
techniques,history of metalwork, history of art
History of art
The History of art refers to visual art which may be defined as any activity or product made by humans in a visual form for aesthetical or communicative purposes, expressing ideas, emotions or, in general, a worldview...
, archaeology
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...
, corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
of metals, scientific research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
methods, theory
Theory
The English word theory was derived from a technical term in Ancient Greek philosophy. The word theoria, , meant "a looking at, viewing, beholding", and referring to contemplation or speculation, as opposed to action...
and ethics
Ethics
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...
of conservation-restoration.
Metals and alloys commonly used for cultural heritage objects
- GoldGoldGold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
- SilverSilverSilver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
- CopperCopperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
- BronzeBronzeBronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...
- BrassBrassBrass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
- NickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
- Nickel silverNickel silverNickel silver, also known as German silver, Argentann, new silver, nickel brass, albata,, or alpacca, is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named for its silvery appearance, but it contains no elemental silver...
- MonelMonelMonel is a trademark of Special Metals Corporation for a series of nickel alloys, primarily composed of nickel and copper, with some iron and other trace elements. Monel was created by David H. Browne, chief metallurgist for International Nickel Co...
- ChromiumChromiumChromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
- IronIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and SteelSteelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten... - Weathering steel(Corten)
- Stainless steelStainless steelIn metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
- TitaniumTitaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
- TinTinTin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...
and PewterPewterPewter is a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and lead. Copper and antimony act as hardeners while lead is common in the lower grades of pewter, which have a bluish tint. It has a low melting point, around 170–230 °C ,... - LeadLeadLead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
- ZincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
- AluminiumAluminiumAluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
Metals and alloys less commonly used for cultural heritage objects
- AntimonyAntimonyAntimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
- MagnesiumMagnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
- NiobiumNiobiumNiobium or columbium , is a chemical element with the symbol Nb and atomic number 41. It's a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite...
- PalladiumPalladiumPalladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...
- PlatinumPlatinumPlatinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...
- RhodiumRhodiumRhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
- MercuryMercury (element)Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
- ElectrumElectrumElectrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. It has also been produced artificially. The ancient Greeks called it 'gold' or 'white gold', as opposed to 'refined gold'. Its color ranges from pale to bright yellow, depending on the...
- TumbagaTumbagaTumbaga was the name given by Spaniards to a non-specific alloy of gold and copper which they found in widespread use in pre-Columbian Mesoamerica and South America.-Composition and properties:...
- ShakudoShakudoShakudō is a billon of gold and copper , mostly designed for its dark blue-purple patina. It was historically used in Japan to decorate katana fittings such as tsuba and kozuka...
- ShibuichiShibuichiis an alloy which can be patinated into a range of subtle muted shades of blue or green. Its name means "one-fourth" in Japanese and indicates the standard formulation of one part silver to three parts copper, though this may be varied according to the desired effect. A 5% silver / 95% copper alloy...
- Bidri
- HepatizonHepatizonHepatizon , also known as Black Corinthian Bronze, was a highly valuable metal alloy in classical antiquity...
Basic techniques
- CastingCastingIn metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process...
- ForgingForgingForging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...
- FoldingFoldingFold or folding may refer to:* Paper folding, the art of folding paper* Book folding, in book production* Skin fold, an area of skin that folds* Fold , in the game of poker, to discard one's hand and forfeit interest in the current pot...
- SawingSawingThe execution by sawing was a method of execution used in Europe under the Roman Empire, in the Middle East, and in parts of Asia. Some sources say that the method was probably never used. The condemned were hung upside-down and sawn apart vertically through the middle, starting at the groin...
- CuttingCuttingCutting is the separation of a physical object, or a portion of a physical object, into two portions, through the application of an acutely directed force. An implement commonly used for cutting is the knife or in medical cases the scalpel...
- BendingBendingIn engineering mechanics, bending characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element. The structural element is assumed to be such that at least one of its dimensions is a small fraction, typically...
- DrillingDrillingDrilling is a cutting process that uses a drill bit to cut or enlarge a hole in solid materials. The drill bit is a multipoint, end cutting tool...
- Filing
- Piercing
- Sanding
- PolishingPolishingPolishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection In some materials polishing is also able to reduce diffuse reflection to...
Some supplementary techniques
- Repousse
- Chasing
- RaisingRaisingRaising may refer to:*Raising , a syntactic construction*Raising , a change in a vowel towards a closer articulation*Raising , a metalworking technique...
- Metal spinningMetal spinningMetal spinning, also known as spin forming or spinning, is a metalworking process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part. Spinning can be performed by hand or by a CNC lathe....
- AnnealingAnnealingAnnealing may refer to:*Annealing , a heat treatment that alters the microstructure of a material causing changes in properties such as strength and hardness and ductility*Annealing , heating a piece of glass to remove stress...
Surface decoration techniques
- Enamelling
- NielloNielloNiello is a black mixture of copper, silver, and lead sulphides, used as an inlay on engraved or etched metal. It can be used for filling in designs cut from metal...
- EngravingEngravingEngraving is the practice of incising a design on to a hard, usually flat surface, by cutting grooves into it. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing...
- EtchingEtchingEtching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal...
- GranulationGranulationGranulation can refer to:*Granulation is the act or process of forming or crystallizing into grains*Granulation tissue, a product of healing in major wounds;*Granular synthesis, a sound synthesis method;...
- FiligreeFiligreeFiligree is a delicate kind of jewellery metalwork made with twisted threads usually of gold and silver or stitching of the same curving motifs. It often suggests lace, and in recent centuries remains popular in Indian and other Asian metalwork, and French from 1660 to the late 19th century...
- InlayInlayInlay is a decorative technique of inserting pieces of contrasting, often coloured materials into depressions in a base object to form patterns or pictures that normally are flush with the matrix. In a wood matrix, inlays commonly use wood veneers, but other materials like shells, mother-of-pearl,...
(DamasceningDamasceningDamascening is the art of inlaying different metals into one another—typically, gold or silver into a darkly oxidized steel background—to produce intricate patterns similar to niello...
) - Mokume gane
- Pattern weldingPattern weldingPattern welding is the practice in sword and knife making of forming a blade of several metal pieces of differing composition that are forge-welded together and twisted and manipulated to form a pattern. Often called Damascus steel, blades forged in this manner often display bands of slightly...
- PlatingPlatingPlating is a surface covering in which a metal is deposited on a conductive surface. Plating has been done for hundreds of years, but it is also critical for modern technology...
- Chemical coloring of metals(Patination´)
- Heat coloring
- Combining metals and other materials
Some contemporary techniques
- ElectroformingElectroformingElectroforming is a metal forming process that forms thin parts through the electroplating process. The part is produced by plating a metal skin onto a base form, known as a mandrel, which is removed after plating...
- 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
- LeatherLeatherLeather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...
- WoodWoodWood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
- PaperPaperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
- FurFurFur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...
- Feathers
- TextileTextileA textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...
- BoneBoneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
- HornHorn (anatomy)A horn is a pointed projection of the skin on the head of various animals, consisting of a covering of horn surrounding a core of living bone. True horns are found mainly among the ruminant artiodactyls, in the families Antilocapridae and Bovidae...
- TortoiseshellTortoiseshell materialTortoiseshell or tortoise shell is a material produced mainly from the shell of the hawksbill turtle, an endangered species. It was widely used in the 1960s and 1970s in the manufacture of items such as combs, sunglasses, guitar picks and knitting needles...
- AmberAmberAmber is fossilized tree resin , which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. There are five classes of amber, defined on the basis of their chemical constituents...
- Plant fiber
- ShellMollusc shellThe mollusc shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes...
- Pearls
- IvoryIvoryIvory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...
- CoralCoralCorals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
- Jet (lignite)Jet (lignite)Jet is a geological material and is considered to be a minor gemstone. Jet is not considered a true mineral, but rather a mineraloid as it has an organic origin, being derived from decaying wood under extreme pressure....
Inorganic materials
- Precious and semiprecious stones(GemstoneGemstoneA gemstone or gem is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments...
) - GlassGlassGlass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
- EnamelVitreous enamelVitreous enamel, also porcelain enamel in U.S. English, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 °C...
- NielloNielloNiello is a black mixture of copper, silver, and lead sulphides, used as an inlay on engraved or etched metal. It can be used for filling in designs cut from metal...
- Ceramics
- PorcelainPorcelainPorcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
- Plastics
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, SEMScanning electron microscopeA scanning electron microscope is a type of electron microscope that images a sample by scanning it with a high-energy beam of electrons in a raster scan pattern...
, electrochemical techniques, metallographyMetallographyMetallography is the study of the physical structure and components of metals, typically using microscopy.Ceramic and polymeric materials may also be prepared using metallographic techniques, hence the terms ceramography, plastography and, collectively, materialography.-Preparing metallographic...
Identification of corrosion processes and products
- Simple method - visual examination,spot tests
- The Oddy testOddy testThe Oddy test is a procedure created at the British Museum by conservation scientist Andrew Oddy in 1973, in order to test materials for safety in and around art objects....
- 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, chromatographyChromatographyChromatography is the collective term for a set of laboratory techniques for the separation of mixtures....
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
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.
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 WaxRenaissance WaxRenaissance Wax is a brand of microcrystalline wax polish that is widely encountered in antique restoration and museum curation. Although not appropriate for all materials, it is known to and used by almost every collection. It is also used as a primary finish for cabinetry and furniture....
/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 boardParticle board
Particle board, or particleboard , is an engineered wood product manufactured from wood particles, such as wood chips, sawmill shavings, or even saw dust, and a synthetic resin or other suitable binder, which is pressed and extruded...
, plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...
) must be avoided. Also do not use rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
, felt
Felt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
or wool
Wool
Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....
.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)
Important persons
- Georg Rosenberg
- William Matthew Flinders PetrieWilliam Matthew Flinders PetrieWilliam Matthew Flinders Petrie FRS , commonly known as Flinders Petrie, was an English Egyptologist and a pioneer of systematic methodology in archaeology and preservation of artifacts...
- Friedrich RathgenFriedrich RathgenFriedrich Rathgen, was a German Chemist and a founder of Conservation science.-Biography:Friedrich Rathgen was born in Eckernförde, Schleswig-Holstein, on 2 June 1862. He began his formal education at the University of Göttingen in 1881 where he studied the natural sciences...
- Alexander Scott
- Harold PlenderleithHarold PlenderleithHarold Plenderleith was a Scottish art conservator and archaeologist.-Biography:Harold Plenderleith was born in Scotland on 19 September 1898....
- 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
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
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
- Roemisch Germanisches Zentralmuseum,Mainz,Ausbildung zum Restaurator des Fachbereischs Archeologie
- Hochschule fuer Technik und Wirtschaft,Berlin, schwerpunkt Archaeologisch-Historisches Kulturgut
- Staatlische Akademie der Bildende Kuenste,Stuttgart,Objekt Restaurierung
- 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
- West Dean College,metalwork conservation
- 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.
25.Ronald Gobiet (Ed.),Die Salzburger Mariensäule - Zur Konservierung monumentaler Bleiplastiken / Sulla conservazione dei monumenti in piombo,Salzburg 2006.
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 Conservation2.The Modular Cleaning Program
3. Download free conservators documentation software
External links
1.ICOM CC WG Metals2. 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