Case Study: 1722 Liverpool Delftware Plaque from Merchant Taylors Boys' School, Crosby, Liverpool
A dated Liverpool delftware plaque; biscuit coloured fabric with tin-glaze and cobalt blue decoration. Decorated with the armorial of Merchant Taylors and motto, and inscribed, “THIS SEAT WAS ERECTED BY JOHN HARRISON AND HENRY HARRISON OF LEVERPOOLE 1722”. This plaque commemorates the purchase of a pew in 1722 by John and Henry Harrison, who were related to the school's original founder, John Harrison. It was sited in St. Michael’s Church in Crosby, Liverpool, on the wall over the pew near the middle of the church. It is thought to have hung in the church until it was demolished in the C19th, after which it was acquired by the school. It was made at the pottery of Alderman Thomas Shaw, which was at the end of Fontenoy Street and Dale Street in Liverpool
On receipt of the plaque, previous repair was present; it had been broken into three sections, repaired with an epoxy resin, missing areas in-filled with epoxy resin and titanium dioxide, and retouched. The alignment of the sections was very good and the joins appeared strong and stable. Retouched and in-filled areas had discoloured and, overall, much dirt was ingrained on the upper and reverse surfaces. Numerous chips and wear were present along all four edges and corners; a characteristic of this type of pottery; as low-fired and with a thick glaze, it is prone to chipping and glaze loss. As the glaze had been applied thickly, it had crawled in several areas, almost peeling and pulling back from the clay body, creating deep pits and exposing substantial areas of clay body, particularly to the right hand side of the plaque.
All over-painting was initially removed using a scalpel blade under magnification. The surface (both back and front) was then cleaned by firstly applying a weak solution of Synperonic A7 and deionised water, applied by stencil brush, followed by the controlled use of a Derotor Steam Cleaner GV.
As much in-fill material as possible was removed with a scalpel blade. The join lines were then painted with deionised water to form a barrier layer, followed by the application of Nitromors, after which the plaque was covered in Clingfilm to concentrate the action of the Nitromors. Prior to this various solvents had been tested to determine which one may reverse the previous repairs. Over two weeks the Nitromors was removed and reapplied, but there was no movement in the joins; it was ineffective. The plaque was finally fumed with dichloromethane in a sealed container for several days; this was ineffective.
It was decided not to continue trying to dismantle the previous joins as this could actually put the object at risk of further damage; the adhesive used in the previous repair was stronger than the ceramic body itself.
All chips, along join lines, edges of glaze and clay body were consolidated with a 20% solution of Paraloid B72 in acetone, applied by brush. The glaze layer was then mimicked using a coloured epoxy paste; a mix of Hxtal NYL-1, Cab-O-Sil ® and Artist’s Dry Powder Pigments.
Once cured, the epoxy fills were refined with various grades of Micro- Mesh™. They were further hand-retouched with Rustin’s Acrylic Water-Borne Ceramic Glaze and Artist’s Dry Powder Pigments. Retouched areas were refined and polished with Micro- Mesh™ . The chipped areas to the unglazed back face of the plaque were filled with a mixture of Polyfilla and Artist’s Dry Powder Pigments. These fills were refined with a scalpel and various sands papers and then retouched with Artist’s acrylic paints.
(Images reproduced courtesy of Merchant Taylors Boys' School, Crosby, Liverpool)
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