Testing and evaluation of treatments
The alum-treated objects from the Oseberg find must be re-treated to strengthen the weakened wood structure and avoid disintegration.
Existing treatment methods
The fragile wooden objects must be treated with an appropriate consolidation material to provide structural support. Existing methods for consolidating wood, as well as neutralizing acid and removing or moderating the effect of harmful metal ions will be critically evaluated and tested in re-treatment trials.
A protocol to test these treatments will look at:
Chemical analysis and imaging: The wood will be chemically characterized before and after treatment. Imaging techniques will be used to study the interaction of the different agents with the wood structure.
How to apply the materials: Most of the delicate Oseberg objects should not be completely immersed in a treatment bath, which is the usual way freshly excavated wood is consolidated. Possible alternatives may be the use of injection or poultices.
Penetration of the material into the wood: The consolidant should completely and evenly impregnate the object, without filling wood cells, for best strengthening effect.
Mechanical and chemical stability: The physical and chemical properties of the wood before and after treatments will be compared.
Different conservation methods for different states of preservation
The wooden objects in the Oseberg collection vary from relatively well-preserved to very degraded. Additionally, many objects are impregnated with linseed oil, and/or coated with an epoxy-based varnish, and there are differences in content and distribution of metal parts. A collection survey will examine objects based on optical appearance (color, condition, surface coating and extent of restoration) and (simple) chemical and mechanical tests. The objects will then be grouped based on their condition and previous treatment to better allow for determination of the optimal re-treatment procedure.