Conservation Department

Object conservation

Paperclay

Research is currently being carried out by NGA Objects conservators in collaboration with Materials Scientists from the Australian National University, to test the viability of paperclay as a gap filler to compensate lost sections in earthenware ceramics.

Paperclay is a material made by the addition of paper pulp to any type of clay. Archaeological ceramics often require treatments that involve the filling of large losses. Clay would be a logical material to choose for this, having similar properties of strength and weight as the ceramic object. Unfortunately, it cannot be used in its raw state and when fired, suffers from a high shrinkage rate. Paperclay was chosen because it is considered to have better working properties, green strength and lower shrinkage rates than ordinary clay. In the initial round of testing, four properties of paperclay, namely shrinkage, working properties, unfired strength and fired strength were tested and the results were published and presented at the AICCM Objects SIG Symposium and Workshop 2005.