Conservation of a 17th Century Font Cover

By Franciszek de Sage

Historical context

This late 17th century font cover comes from Saint Magnus the Martyr Church near London Bridge which is recorded in a confirmation of a grant made by William the Conqueror to Westminster Abbey in 1067. The medieval church was repaired in the early 17th century and completely rebuilt by Christopher Wren after the Great Fire of London in 1666. The total cost of the work was £9,580 and made it one of the most expensive churches rebuilt by Wren after Great Fire. The font cover possibly is from that period, but there is no evidence it is based on Wren design.


The cubical of the font cover is made of oak with an octagonal moulded base and floral carvings on each of four sides. At first glance they look like a frame and panel construction, but unusually they are made from a solid piece of wood and attached to the rail on the inside. The domed top is built around a cross section that sits on the rails. The gilded metal hook with four cherub faces is attached to the inner cross section.

Condition before treatment

A frame and panel construction allows for movement in the wood; however, as this cover was made from solid pieces, many elements had cracked and become loose. The sides were cupped, pushing apart the octagonal base and moulded arches creating large gaps (up to 12 mm). When the font cover was lifted, the weight of the cover caused cracks to form on the domed top. Most of the gaps were filled in previous repair with a wood dust and animal glue-based gap filler, which had responded to fluctuations in humidity and come loose. The main treatment goal was to make it structurally sound and to reduce the visual impact of the multiple gaps.


First stage of the conservation was to dismantle all the loose parts, remove old adhesive and re-glue using hot animal glue. The octagonal base was glued back with specially made jig to ensure that all 8 corners met accurately.

The surface under the arches was cupped and it was not possible to place them in the right position with conventional clamps, so fibreglass shimbari clamping sticks were used to give better control with more pressure points.

Because the sides were so badly cupped it was impossible to close most of the gaps not putting more stress into construction. To fill the gaps with slivers, balsa wood was chosen because of its low compression modulus. It was especially important because of a much different conditions in the workshop and the church which has a fluctuating environment. All the slivers were slightly lower than the surrounding parts so reduce their visual impact.

Previous poor repair patches, (which had incorrect shape and grain direction), were replaced with better fitting ones in oak.

The final stage included cleaning the surface with cotton swabs and de-ionised water. Gentle abrasion with the cotton swabs mechanically removed a top layer of modern varnish, which was poorly attached to the underlying surface. The balsa wood fills were coloured using acrylic paint and a thin layer of beeswax was applied and buffed to add a degree of shine to the surface.