QUEENSLAND'S GERMAN CONNECTIONS - PAST, PRESENT AND FUTURE

Lots of good inhibitions Mephisto

The conservation work began in October 2011 and was approaching successful completion a year later. The most time-consuming part of the treatment has been the cleaning of the interior and exterior surfaces. This was more thorough than that of the initial flood response and carried out in a similar manner, although the use of water was restricted. Stiff brushes, vacuum cleaners and compressed air were used to dislodge dirt and grime, and the surfaces were degreased to remove potentially damaging impurities. The corroding steel plate was cleaned and degreased before being treated with a corrosion-inhibiting wax emulsion. The tracks and drive mechanisms that had been submerged during the flood were inspected using an endoscope to check for internal corrosion. They were also cleaned and degreased, then coated with a protective inhibitor. Water was drained from the gearbox and both it and the engine compartment were flushed several times with a degreasing solvent before being filled with a corrosion-inhibiting solution. ‘Vapour phase inhibitors’ added to the engine and gearbox com partments and new bungs will limit air transfer and prolong the effectiveness of the inhibitors. The final stage of the treatment will be to in-paint the losses in the exterior painted surface to reduce the visual impact of the white undercoat spots on the tracks. Once the treatment is complete, a maintenance program of regular cleaning and replacement of inhibiting solution will be implemented and a conservation strategy for care of Mephisto will be developed and formalised, to help to guide decision-making around the preservation of Mephisto for many more years to come.

Above: QM technician Trevor Harvey drains fluid from Mephisto’s engine, and (below): conservator Jennifer Blakely and technician Steve Baker use an endoscope to inspect interior components.

The interior paint system has been largely lost and there was a build up of dirt and grime evident on the inside surfaces. This was not unexpected as, due to its relative inaccessibility while on display, the last documented clean of the interior space took place in 2008. Deterioration of the metal components has been relatively minor over the years, although there is evidence of galvanic corrosion occurring between electrochemically dissimilar metals in the engine and on some of the fittings. The engine and drive compartments were in reasonable condition but covered with a thick oil. An inspection of the gearbox revealed it to be full of water, which may have entered during the initial high-pressure water cleaning. As well, active corrosion was discovered in a section of steel plate in the floor below the gun emplacement, probably due to of the high humidity levels reached during the flood. The low level of overall deterioration observed is a result of Mephisto being displayed in a dedicated environmentally-controlled space. Thus, major intervention was not necessary and conservation work proposed focused on ensuring that all water from the flood and subsequent cleaning was removed, any corrosion in the internal spaces stabilised, the gearbox and engine components were maintained, and that aesthetic considerations, such as the white undercoat spots, were addressed.

Mephisto’s engine and gearbox compartments are filled with a corrosion-inhibiting solution.

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