Conservation and restoration of iron and steel objects

The conservation and restoration of iron and steel objects is an activity dedicated to the preservation and protection of objects of historical and personal value made from iron or steel. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer.

Historically, objects made from iron or steel were created for religious, artistic, technical, military and domestic uses. The act of conservation and restoration strives to prevent and slow the deterioration of the object as well as protecting the object for future use. The prevention and removal of surface dirt and corrosion products are the primary concerns of conservator-restorers when dealing with iron or steel objects, including nickel-iron meteorites.

An pillar, slightly fluted, with some ornamentation at its top. It is black, slightly weathered to a dark brown near the base. It is around 7 meters (22 feet) tall. It stands upon a raised circular base of stone, and is surrounded by a short, square fence.
The iron pillar of Delhi is an example of the iron extraction and processing methodologies of India. It has withstood corrosion for the last 1600 years.

History

Main article: Ferrous metallurgy

Metallurgy

Main article: Ferrous metallurgy

Conservation

Historical objects

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.

Research

Identification of metals and alloys

Identification of corrosion processes and products

Identification of materials associated with metals

Identification of technology used to produce objects

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.

Cleaning

Chemical Electrochemical Mechanical Ultrasound Laser Plasma
Ammonium citrate 5% / pH 3.5[1]

Phosphoric acid 10 - 20% + 1% tiourea[2]

EDTA 4% pH 5.5[3]

Thioglycolic acid 3-30% pH 7[2]

Polymethacrylic acid 10-15% pH 4.5 - 5.5[4]

Mixed organic acids

47.5 g citric acid

47.5 g sodium gluconate

4.9 g tartaric acid

1 L water[5]

 2-5 % NaOH, stainless steel anodes + Ecorr measurement! Precipitetd chalk/water mixture

fine steel wool

scalpel

micromotor and steel/or bristle brushes

microsanblasting unit

 NaOH 5-19 g

sodium carbonate 15-25 g

trisodium phosphate 49-60 g

water 1 L

Immerse objects 2–5 minutes, rinse well, repeat if needed.[6]

 Can be used[7] Can be used[8]

Blued, browned or blackened objects must be cleaned only with Balistol, WD 40 or petroleum/parafine solution.

Painted objects must be cleaned with polar/non polar solvents or solvent mixtures.

Structural consolidation

Screws,rivets,gluing,soldering,welding

Stabilization

Protective coatings

Archaeology objects

Cleaning

Only mechanical cleaning can be used(scalpel,micromotor and steel brushes and abrasive discs,microsandblasting unit,ultrasonic chisel).

Structural consolidation

Gluing only can be used,reversible types are the Best. Glass fibre reinforcments can be used too.

Stabilization

Protective coatings

Preventive conservation

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. Iron objects with active corrosion up to 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) [54]

See also

Further reading

Article: U. Peltz und O. Zorn (Hrsg.): KulturGUTerhalten. Standards in der Restaurierungs- wissenschaft und Denkmalpflege. Mainz 2009, p. 91-95

References

  1. ↑ H.Brinch-Madsen, "Die reinigung von eisen mit ammoniakalischer Citronensaure", Arbeitsblatter fur Restauratoren 2/1974
  2. 1 2 Stambolov,T.; Eichelmann,N.; Bleck,R.D. Korrosion und Konservierung von Kunst und Kulturgut aus Metall / I. Weimar 1987.
  3. ↑ Stambolov,T.;Eichelmann,N.;Bleck,R.D. Korrosion und Konservierung von Kunst und Kulturgut aus Metall / I. Weimar 1987.
  4. ↑ Nikitin,M.K.; Melynikova,E.P. Himiya v restavracii, Leningrad 1990.
  5. ↑ USPT 4,264,418
  6. ↑ Dasojan, M.A.; Palmskaja, I.J.; Saharova, E.V. Tehnologiya elktrohimicheskih pokritiy, Leningrad 1989.
  7. ↑ 1.Cooper, M.I. (2002) Laser cleaning of metal surfaces: an overview. Paper presented at the UKIC Metals Section ‘Back to Basics: Surface Treatments’ conference (Liverpool, October 1999). Published in ‘Back to Basics, The Metals Section' Press, 34-39.
  8. ↑ "NMA metals" (PDF). Retrieved October 1, 2013.
  9. ↑ 40 Logan. J., "Tannic acid treatment*. CCI Xotes 9/5, Canadian Conservation Institute. Ottawa (1997).
  10. ↑ Stambolov, T.; Eichelmann, N.; Bleck, R.D. Korrosion und Konservierung von Kunst und Kulturgut aus Metall / I. Weimar 1987.
  11. ↑ Gilberg, M.; Seeley, N. The Alkaline Sodium Sulphite Reduction Process for Archaeological Iron: A Closer Look, Studies in Conservation, London 1982.
  12. ↑ accessed May 23, 2012
  13. ↑ Sjogren, A.; Mathiesen, T.; van Lanschot, J.' Turgoose, S., and Hawkins. C 'Rapid low-temperature hydrogen plasma treatment of archaeological iron'. Zeitschrift für Schweizerische Archäologie und Kunstgeschichte 54 (1997) 34-40.
  14. ↑ "The application of subcritical fluids for the stabilization of marine archaeological iron". iiconservation.org. Retrieved November 28, 2014.
  15. ↑ "Maney Online - Maney Publishing". maneyonline.com. Retrieved November 28, 2014.
  16. ↑ "Painting Historic Ironwork". buildingconservation.com.
  17. ↑ "Restoration of Antique Wrought Ironwork". buildingconservation.com.

External links

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