Wooden barrel with iron bars

A wooden barrel full of small iron bars was lifted from a medieval
wreck-site in the Finnish coast of the Baltic Sea in 2006. The iron
had corroded readily during the centuries of submersion forming a
concretion around the whole barrel and infesting the wood badly with
corrosion products.  Upon excavation in the lab about half of the
largely mineralized iron bars were removed and subsequently
stabilized. The remaining whole still consists of hundreds of iron
bars corroded together and several wooden planks of the barrel.

It is now dry and the plan is to leave it like that and display it
partially excavated. The problem is how to stabilize and display
such a composite artifact. Although the iron bars are largely
mineralized and seem to retain the shape well, there is still
substantial weeping. A display case with stable environment would be
one option, but defining the ideal conditions is difficult. Dryness
would stop corrosion but the wood might suffer. Any ideas of how to
approach this problem would be greatly appreciated.

Ulla Klemela, conservator
The National Board of Antiquities
The Maritime Museum of Finland
Hylkysaari
FI-00570 Helsinki
Finland


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                  Conservation DistList Instance 23:16
                 Distributed: Friday, November 6, 2009
                       Message Id: cdl-23-16-013
                                  ***