Section 4: Composite artefacts (PDF 20858kb) - National Museum of ...

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Proceedings of Metal 2004 National Museum of Australia Canberra ACT 4–8 October 2004ABN 70 592 297 9673.4.2 Observations of GP300 Active Rust Inhibitor (ARI)All the promise of ARI has not been fully realised within the studies so far conducted.Ongoing product development coupled with regular formula changes has resulted in much effort forlittle useable return. Practical experience with ARI has taught that the product can require a variablenumber of coating applications depending on the degree of surface corrosion and the formula of thesolution. The changing formula during the development phase meant that some product batchesseparated in the container and this contributed to uneven and flawed coatings that for a period not onlyallowed recorrosion but potentially accelerated the phenomena. Subsequent re-application was requiredto obtain good coating distribution.Unfortunately all the questions initially posed for this product have not been answered, sinceeach new formula has fundamentally changed the characteristics of the product. The effectiveness ofARI can only be ascertained once the product’s development is completed and this is not yetforeseeable.3.4.3 PaperSince one of the rationales for trialling ARI was its potential suitability to consolidate both acorroded can body as well as a can’s label in situ, the effects of ARI on paper alone were trialled atCape Royds in 2001 with a range of concentrations applied to acid free paper. This paper experimentwas observed as recently as February 2004 and at that time, no deterioration, yellowing or staining ofthe paper swatches coated with ARI had occurred (Clendon and Bickersteth 2004).3.5 Observations of object treatment off-site versus on-siteOff-site conservation and replacement has been an effective model for the treatment of a verysmall number of selected artefacts. Difficulties in packing and transport from the ice werecircumvented by a careful choice of artefacts. Observations conducted annually since 1997 haveshown that Karel Peter’s 1987 objects returned to Cape Evans and Peter Maxwell’s 1998 objectsreturned to Cape Royds, post off-site treatment, have remained predominantly stable with only twoartefacts recorroding. This statement is subject to one very important caveat: none of these returnedobjects were relocated in a high risk microenvironment.In situ interventive experimentation which included treatment applications on corrodingartefacts has had mixed results. Prior to 1997 commercial products were applied to artefacts if atreatment was considered required. The most significant example of this was a polyurethane coatingapplied to the stove at Cape Royds.Since significant issues regarding the transport and use of commercial products in Antarcticaexist, ARI was trialled as an alternative product during its developmental phases. The subsequentdifficulties with ARI have been previously outlined and no baseline for comparative purposes was everestablished. Best applications of ARI were achieved when halogen lamps were shone onto the metalsurface, warming the environment and object surface. The re-treatment done at the rear of the CapeRoyds stove in 2000 best exemplifies the effectiveness of this method. Applications of any water borneproducts generally are applied above 10 o C for maximum performance.On the whole, in situ conservation is seriously constrained by the simple logistics of workingin Antarctic conditions and complying with Antarctic environmental requirements. It would be bold toput forward a view that an effective interventive conservation program encompassing all artefactscould be conducted within the existing framework of camping on the ice.4. ConclusionsIn regards to the conservation of outside objects, the current conditions and technology is suchthat no viable metal conservation treatment program can be conducted. Some preventive conservationwork may be suitable for a portion of this collection. The universal presence of chloride ions both as anaerosol or as salts in the earth and ice, combined with the effects of wind ablation and moistureavailability are usually beyond any control.Observations inside the huts, supported by the environmental data collected by Held et al2003, stress the importance of recognizing the effects of variation in environmental conditions betweenthe huts and within each hut when trying to preserve or prioritise the preventive or interventive© Published by the National Museum of Australia www.nma.gov.au497
Proceedings of Metal 2004 National Museum of Australia Canberra ACT 4–8 October 2004ABN 70 592 297 967conservation needs of interior artefacts. Artefacts located near the floor or outside walls havesignificantly increased rates of deterioration associated with greater moisture availability.During summer the RH is high and the temperature is above freezing. The potential and rate ofcorrosion activity is consequently much higher, and a focus on reducing the RH within the huts duringthese periods should result in a significant reduction in general corrosion rates and a universally morebeneficial environment for the interior artefact assemblage. It does appear from data acquired by Heldet al 2003 that visitor numbers to the huts have no significant impact on RH inside the huts.The major process of deterioration for metals inside the huts has been observed to be one ofcyclic corrosion, developing from pitting to sheet like corrosion. Obviously the presence of chlorideions will further accelerate this process on a case by case basis. Results from sampling and analysisshow that the presence of chloride ions is far from universal within the inside artefact assemblages.A full range of conservation practices is not recommended for all objects. Some objects insidethe hut have not been exposed to the outside environment or damp areas inside the hut and are notassessed as either significant or iconic. Objects which were located outside the hut prior to 1960, andthat have been brought inside because of their significance, have a range of conditions.The challenge put forward by the AHT is to preserve the large number of food cans in thecollection, where conditions vary from pristine to very poor. Treating objects off-site has been mainlysuccessful, however, the treatment of this wide range of objects is a costly and slow exercise. In theauthors’ view it is currently only possible to treat metal objects effectively off-site in a controlledenvironment, on-site activities should be restricted to preventive conservation only. For the long termconservation of the collection in situ the challenge is to stabilise the interior of the huts, and minimisethe effects of relative humidity in summer.AcknowledgementsThe authors would like to acknowledge New Zealand Antarctic Heritage Trust and team members ofK282, K440 and K021 and National Science Foundation BO-038-0. Thanks must go to Antarctica NewZealand staff in Christchurch and at Scott Base. Particular thanks goes to Ben Held, Joel Jurgens andRobert (Bob) Blanchette for use of their environmental data and to Robert Clendon and JulianBickersteth’s for their observations in 2003.Materials and suppliersGalmet Ionize A rust converter and sealer consisting of resin vinyl/vinylidene Chloride acryliccopolymer. ITW Polymers & Fluids. 100 Hassall Street, Wetherill Park, NSW, 2164 Australia.Tel: (02)9757 8800 Fax: (02) 9757 3855Dinitrol AV8 sulfonate corrosion inhibiting compound in an aliphatic hydrocarbon base GibsonChemical Industries. 138 Kingston Road, Underwood QLD 4119.Tel: (07) 3208 9333 Fax: (07) 38084865.Dinitrol 4010 A high temperature polyester modified wax dispersed with inhibitors Gibson ChemicalIndustries. 138 Kingston Road, Underwood QLD 4119.Tel: (07) 3208 9333 Fax: (07) 3808 4865Ferroguard Full Spectrum A solution of vinyl copolymers and organic corrosion inhibitors in anisopropanol base Senson Technology Pty Ltd Unit 1/69 Division Street, Welshpool, Western Australia,6106.Tel: 61-8-9358 3388 Fax: 61-8-9358 3390Valvoline “Tectyl 506” A wax emulsion with inhibitors present. Automotive outlets, e.g. Bumper toBumper, AutoBarn, ThompsonsActive Rust Inhibitor GP3000 (ARI) A water based polymer inhibiting product which has excellentproperties to maintain an “as found” appearance. Cairns Corporation Pty Ltd, 221 Brisbane Street,Ipswich, QLD 4306. Tel: (07) 5426 7285 Fax: (07) 5426 7589Rusticide A tannic/oxalic acid product used for converting active rust to a stable surface. Finish ismatt black, but requires overcoating to give maximum performance. A water based product. Flo-KleenProducts, 216 Balcatta Road, Balcatta, WA 6021. Tel: (08) 9345 3122© Published by the National Museum of Australia www.nma.gov.au498
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