Mammal Bones Conservation

Over the next year, Worcestershire Archive and Archaeology Service and Museums Worcestershire are working on a Heritage Lottery funded project to celebrate Worcestershire’s Ice Age past through exhibitions, events, blogs and workshops.

As part of the project, conservation work is being carried out on some of the earliest items that came into the Worcester City collection.

No.128 Bos / bison skull and horn cores from Bricklehampton.

Ice-age conservation

This specimen was in several pieces (see image below). It had clearly been put together in the past with glue and plaster of paris, with a wooden dowel inserted into the left side of the skull and into the left horn core, held with plaster. The plaster had given way.

The edges of breaks were consolidated with Paraloid B72 consolidant and then pieces were glued back together with Paraloid B72 adhesive. The wooden dowel was re-used as support is required for the large, heavy left horn core. Once the adhesive had set, plaster was applied around the dowel inside the horn core. NB there is a metal rod acting as a supporting dowel in the tip of the right horn core. Large cracks were filled with plaster of paris. All plaster was painted to closely, but not perfectly, match the surrounding bone so that an expert eye can tell where the gap-filler is.

Ice-age conservation2

Above, the repaired specimen with the plaster unpainted. Below, with the plaster painted.

Ice-age conservation3

No.173 Taurus primigenius horn core from Eckington.

The proximal end of this horn core was in several pieces. Many could be relocated, but not all.

The edges of breaks were consolidated with Paraloid B72 consolidant and then pieces were glued back together with Paraloid B72 adhesive. Once the adhesive had set, large gaps were filled with plaster of paris to provide additional strength and robustness to the specimen. All plaster was painted to closely, but not perfectly, match the surrounding bone so that an expert eye can tell where the gap-filler is. One piece of bone in this bag does not belong to this specimen.

Ice-age conservation4 Ice-age conservation5

Above left: the specimen before repair. Above right, the specimen after repair.

No.143 Bison priscus limb bone from brickyard

Ice-age conservation6This specimen was in two pieces, where an old repaired break in the mid-shaft had failed. Old glue was removed with a scalpel, the edges of the break was consolidated with Paraloid B72 consolidant and then the two pieces were glued back together with Paraloid B72 adhesive.

General

All the specimens were inspected to see what further conservation work was required. As the surfaces were generally quite friable and fragile, only limited cleaning could be undertaken. This consisted of using an airbrasive unit utilising compressed air laced with a small amount of sodium bicarbonate powder, followed by cleaning with just compressed air. A few vulnerable friable areas were consolidated with Paraloid B72 but this was kept to a minimum so as not to adulterate the specimens.

Thanks to Nigel Larkin for this report.

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