Shipping containers have become an icon of Christchurch City’s skyline over the past few years and the Air Force Museum tarmac is no exception. After decanting the Canterbury Rugby Football Union’s artefacts onto Recovery Centre shelves, naively I thought I would never need to see the inside of a metal box again, but there I was standing at the back gate waiting excitedly for another shipping container to arrive.
Freezer shipping container arriving on the Air Force Museum tarmac
As you can imagine, with objects coming into this space from all corners of the city at speed, pest control is one key factor that any museum professional would be wary of. As groups have been working through their collections, items showing signs of infestation have been isolated in plastic bags for monitoring. If infestation was found to be active, a treatment procedure would be discussed with a conservator and carried out according to their instructions. But what do you do with large objects?
Some groups in the Recovery Centre had large wooden objects with signs of Anobium Punctatum, also known as house borer. Borer is an evil little creature, their larvae living deep within wooden objects. When flight season comes around they burrow out of the object leaving a trail of dust, ready to fly off and take their place in the circle of life.
While using some form of treatment may work to kill flying insects, every year the root of the problem – the emerging bugs – starts the infestation process all over again. Therefore a treatment that kills the babies is the ultimate solution.
Double wrapping a piano from the Lyttelton Museum collection in polythene ready for freezing
After consulting a conservator, freezing these large objects was deemed the best way to go. So groups started off by rechecking their large objects for signs of borer. If dust was found, items were double wrapped in polythene, to insure that during the freezing process no condensation would land on the surface of the object, causing damage. Once this task was completed, items were placed in a holding area until they could be loaded into the freezer shipping container. For an effective kill the freezer was set at -20C for a week, slowly brought up to room temperature, then dropped back down again for a week; this insured that anything fooled into thinking it was summer would be caught in the second freeze. After this additional freeze the temperature was slowly brought back up again and the container emptied ready for the next load. After a month the process was complete, notes were added to catalogue records and the container was returned back to its original home.