How to make a Coade sculpture

Landmark's Historian Caroline Stanford takes us through the process of making Eleanor Coade's eponymous artificial stone that was favored by the great Georgian architects of the day.

It’s a mistake to think that in its replication, Coade stone was mass-produced. It was rather a highly skilled process involving many different stages.

First, a skilled sculptor would create the model figure, carefully sized to be about one thirteenth bigger than the desired final result (since this was the shrinkage that could be expected in the kiln). A plaster mould was taken of this model. Once dry, this cast was cut into two or more pieces.

Eleanor Coade produced catalogues showcasing Coade stone's potential. Image: Sir John Soane's Museum
 

Meanwhile, the ingredients for the Coade stone were assembled, and the dry constituents ground to just right fineness for the particular piece, using a grindstone turned by hand. After combining everything in a trough, the raw mixture was rolled into a flat sheet perhaps half an inch to an inch  (1.5 - 3 cm) thick. This sheet was then pressed by hand into the mould pieces – the craftsman’s or –woman’s fingerprints are often still apparent on the inside of Coade pieces. Turned out, these impressions were carefully reassembled, using iron rods to hold them together in the case of larger works, and allowed to dry in the air until the clay had hardened to something like leather. The pieces were then dismantled again to be fired in the kiln (contrary to the impression given by contemporary engravings, the wood fired kilns were could not be very large, no more than two meters or so in diameter, to ensure even heat penetration).

The kilnsman’s job was a highly skilled one, requiring him to work through the night during firing to keep the temperature constant, and he was paid more than other employees. After firing, the pieces were cooled and then reassembled with great accuracy, reinserting the iron rods and concealing the joints with slip.

250 years of frost and rain later, most of Coade stone pieces are as crisp as the day they came out of the kiln. When we restored Belmont, we were astonished by the revealed detail of the female keystones’ lace collars, and the dimples on the acorn cups in the cornice frieze. Indeed, the only weakness in Coade stone is very often the corrosion of the iron rods inside.

Before and after cleaning Coade stone at Belmont in Lyme Regis

 


Learn more about Eleanor Coade and Belmont

Mrs Eleanor Coade

Where to find Coade stone

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