Blog

It's a wrap! How to bag a canoe

By: Heather Mackay, Category: Science, Date: 20 Oct 2011

Why would our Materials Conservation team put a 14.5 metre canoe in a plastic bag?

That's exactly what the Museum's online producer asked me when we uploaded this video. Well, here's my answer (along with some more of his questions and some more of my answers!):

What you can see is a large wooden 14.5 metre long war canoe from the Solomon Islands. It's being manoeuvred from its storage position into an open area where it can be sealed in a high barrier film bag for low oxygen fumigation. We are doing this because of a suspected insect infestation and we want to prevent any further damage occurring. The bag was made by heat-sealing four 18.5 metre long panels together. It's being fed under and wrapped around the canoe. The ends are heat sealed together to make it air tight. Once this is done, the fumigation process can begin.

Q. What fumigation techniques does the Museum use?

The Museum uses two types of insect fumigation, low oxygen and freezing. In low oxygen treatments, oxygen is purged out of an enclosure, such as a bag or chamber and humidified nitrogen is pumped in. We aim to get the oxygen levels down as low as 0.3% and maintain that for at least 3 weeks. When objects or specimens are frozen they need to stay in -18ºC for a few days. Both these fumigation methods are non-toxic (to humans) which is important as in the past pest treatments have not always been so.

Q. What can you tell us about this canoe?

The canoe was donated to the Museum in 1915. It comes from the Roviana region of the Solomon Islands and it's constructed of planks of timber sewn together with plant material and sealed with a caulking compound to make it water tight. The exterior is painted black and is heavily decorated with inlaid pearl shell. It is quite rare and is the Museum’s largest artefact. It was on display it what is now the Museum’s Indigenous Australians Gallery for 60 years from the 1920’s-1980’s. It's now in storage.

Q. And did you successfully protect it?

Yes, we did. We overcame some problems with innovative solutions which allowed the treatment to be carried out under the right environmental conditions. It was a unique experience to successfully treat such a large object and in fact it is the subject of a paper I’m co-presenting at the British Museum next week.