Conservation of Historic Metals by Waterjetting Techniques

Abstract

Water cleaning has long been used in the conservation of historic metal artefacts and structures and has been fairly well documented in the conservation literature. Typically, low and medium pressure (not exceeding 4,000 psig) water cleaning techniques such as nebulous mist, steam, and power washing have been used to assist the conservator in implementing conservation treatments, not only because they are safe and effective, but also because conservators are not usually fully versed in the principles and technology behind high and ultra-high pressure waterjetting. High to ultra-high pressure (4,000 psig to 50,000 psig) waterjetting is a specialized technique that has been utilized in the commercial cleaning and surface preparation industry for years but has only been used in the conservation field on a handful of projects. In addition to low and medium pressure cleaning techniques, the authors have used high and ultra-high pressure water cleaning techniques extensively on historic metal artefacts for the removal of coatings, corrosion products and soluble salts while making it possible to preserve desirable original coatings and patina materials.

In metal conservation there exists a delicate balance between the goals of the conservation treatment including surface preparation, with its technical aspects of surface profile or roughness, visible cleanliness, and non-visible cleanliness, and ethical issues of minimal intervention and maximum preservation of original material. Since the late 1980s, conservators have studied the effects of medium and high (not exceeding 35,000 psig) water pressures on bronze monuments in an attempt to replace abrasive blasting techniques to remove unwanted corrosion products while still retaining the aesthetically desirable patina layers. Since then, the authors have performed testing and implemented treatments on steel and aluminium historic artefacts using high and ultra-high waterjetting techniques.

This article will provide a practical introduction to waterjetting technology with specific cases of its use in the conservation of metals. A brief recounting of the application of low to medium pressure waterjetting techniques used by outdoor sculpture conservators will be provided, followed by recent applications of high and ultra-high pressure waterjetting in the conservation of the ‘Big Piece’, a salvaged steel hull section from the Royal Mail Ship (R.M.S.) Titanicwreck-site and for the conservation of two Saturn V rockets on display at Johnson Space Center in Houston, Texas and the United States Space & Rocket Center in Huntsville, Alabama.

Additional information

Notes on contributors

Joseph Sembrat

Biography

Joseph Sembrat, President and Senior Conservator, Professional Associate, AIC

Joe Sembrat has been immersed in the conservation field for over 14 years providing conservation assessments, design, and implementation of conservation treatments and lecturing on relevant topics in the field. His extensive experience in the treatment of masonry and metals led to the development and creation of the unique firm Conservation Solutions, Inc (CSI) which he co-founded with his wife, Julya, in 1999 excelling in the treatment of historic monuments and sculpture, industrial artefacts, and buildings. High-profile projects include artefacts from the salvaged R.M.S. Titanic wreck-site, such as the ‘Big Piece’, the conservation of two Saturn V rockets, the treatment of 12 sets of over life-sized bronze gates at the US Commerce Department Building in Washington, DC, and a nineteenth-century Cotton Gin facility located in Scott, Arkansas. Sembrat achieved his Professional Associate status in AIC in 1996 and served as the Architectural Specialty Group Program Coordinator and Chair from 2000 to 2002.

Patty Miller

Patty Miller, Conservator, Professional Associate, AIC

Patty Miller has been an active participant in the preservation field for more than ten years. As a conservator and project manager for CSI, Patty directs surveys, investigations, testing programs and treatments of historic architecture, monuments and artefacts. Since joining Conservation Solutions Inc. in 2003, she has been pivotal in the expansion of the in-house testing laboratory which enables CSI to service such diverse projects as the restoration of two Saturn V Rockets, the conservation of hundreds of artefacts salvaged from the R.M.S. Titanic wreck site, including the 17-ton ‘Big Piece’ of the Titanic hull, and numerous analyses of historic building materials dating from the seventeenth to twentieth century. Patty Miller's breadth of experience in conservation and her dedication to education within the field of preservation is evident by her resume of lectures and papers. Most recently, Patty has had the opportunity to participate as an instructor at the 2004 Cemetery Monument Conservation Seminar and Workshop held by the National Center for Preservation Technology and Training, and co-author of a paper on ‘The Use and Effectiveness of Dispersed Hydrated Lime in the Conservation of Monuments and Historic Structures’.

Jee Skavdahl

Lydia M. Frenzel, Chief spokesperson for the Advisory Council

Lydia M. Frenzel is a professional member of the National Speakers Association. Lydia is a native Texan with a Ph.D. in Chemistry from the University of Texas, 1971. Lydia donates significant time, primarily as a Chairperson, to standards organizations such as ISO, NACE, and SSPC, and is a director for 1995–2007 for the WaterJet Technology Association. Among her recognitions are: Steel Structures Painting Council 1996 Technical Achievement Award; Alpha Gamma Delta Sorority, Distinguished Citizen Award, 1997, and Rotary International District 5190 Governor 1997–98, and selected by JPCL as one of the ‘Twenty people who have helped change the protective and marine coatings industry in the past 20 years’.

Lydia Frenzel

Jee Skavdahl, Project Manager

Jee Skavdahl joined Conservation Solutions, Inc. in December 2003 as a Conservation Technician and now serves the firm as a Project Manager for the Saturn V rocket conservation project at the Johnson Space Center in Houston, Texas. She has been closely involved in the management of both the treatment of the Saturn V and in the construction of the temperature and humidity-controlled building which currently houses and protects the Saturn V during the preservation process. Jee Skavdahl holds a Bachelor of Science in Physiological Science from the University of California, Los Angeles, California.