Conserving a previously restored glass flagon

This amber-coloured, glass flagon, found in Buckinghamshire, had been previously restored, possibly in the 1970s. The old gap-fills were discoloured and crude in appearance and needed to be replaced.

Gap-filling missing areas of glass requires a high level of skill and knowledge. Conservators at The British Museum make detachable epoxy resin gap-fills to replace missing areas of glass where possible. This involves a lengthy process of modelling, moulding and casting.

The old restoration was removed and the glass cleaned with solvents. Once this glass flagon was assembled the areas to be filled were protected with aluminium foil and filled with an opaque, white, polyester paste using a sheet of dental wax for support. When hardened, the polyester gap-fill was detached from the flagon and sanded to a smooth surface. Using the polyester gap-fill as a template, a silicon rubber mould was produced. The conservator cast the rubber mould with an epoxy resin. Once set, the epoxy resin gap-fill was polished to a glassy finish and colour-matched using translucent amber-coloured paints. This process was repeated for each of the missing areas. The epoxy resin gap-fills were bonded into position using a reversible adhesive. The advantage of this technique is that all the work on the gap-fill is carried out away from the object, protecting the fragile glass from damage during fitting.