The Thames river has been a great maritime route and economic resource throughout much of human history. It has also been a place for people to discard waste and rubbish, resulting in a large archaeological record. Mid-way through our second term we were given the chance to conserve leather objects from the Thames.
The aims of conserving the leather from the Thames were to ensure its stability. When we first received the objects, they were kept in polythene bags with water. If waterlogged leather is left to dry with no treatment it will become brittle and crack, therefore it required conservation treatment to stabilise.
First, we cleaned the leather using a thin stream of tap water and a soft bristle brush over a sink, using a mesh net to catch any fragile parts of the object which might be removed. It was important to keep the stream of water thin so as not to damage the leather further. I chose a leather shoe to conserve, and as I was cleaning, it became apparent that the shoe (although it appeared whole at first) was lots of different pieces of one shoe.
The leather was placed into a 20% glycerol solution for two weeks before being rinsed of any excess. Pieces of leather which were flat were placed between two pieces of cardboard so they would hold their shape when they were put in the freezer. They remained in the freezer for two days before being put into the freeze dryer for one week. Some of the objects, such as shoes, were three dimensional therefore pieces which were supposed to be standing had to be supported by sand bags and acid free tissue paper while they were in the freezer so they would hold their shape.
Once the leather was taken out of the freeze dryer it was appropriately repackaged. I chose to repackage the shoe in a cardboard box with shelving and plastazote to support the individual pieces all in one place. The plastazote stoppers ensured that any delicate pieces did not roll around while in storage.
Some leather had iron corrosion on them after being in the freezer, due to the way the objects had been manufactured and put together. This iron corrosion was stabilised using an appropriate solution so it wouldn’t continue to corrode while in storage.
Post-conservation the colour of the leather is lighter, however that is to be expected as it has dried out. It is still somewhat flexible, though not as flexible as before treatment. The shoe which I conserved originally came as one object, however I chose to repackage it as separate pieces. The shoe was repackaged in one box, though shelves made from acid free card and plastazote were put in so that each piece could sit in the box with support.
Katie.