Kiln furniture from North Hylton

​Right, a saggar recovered from the North Hylton site.  Saggars were used to shied delicate pottery items in bisque state from the high temperatures of the first firing.  Ruffel writes that they were 'made from thick "grogged" fireclay – that is clay mixed with crushed pottery to give it a coarse texture – to withstand high temperatures'.

In this case it looks as if the saggar was constructed in sections and pottery placed carefully inside.  See page 10 of Bell's book on Tyneside Pottery for an image of plates being stacked within enclosed, oval-shaped saggars.
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Photo Keith Cockerill

Bell writes,  'When hard and dry the vessels were placed in saggars and stacked in the biscuit kiln.  When the latter was full the opening was bricked up; fires lighted beneath were kept stoked for 48 hours (maintaining a temperature of approximately 1200 degrees C) and then allowed to go out.  About three days later the kiln was unbricked and emptied.  The ware in its biscuit state was hard, brittle, and porous like a plant pot'.

In order to stop plates and other items fusing together in the firing, spacers and stilts of various descriptions were interspaced between the items.  It's not uncommon to find indentations (stilt marks) on plates and plaques made by kiln furniture.  See various examples below of ring stilts and tripod stilts found at the North Hylton site.

Below left, a large lump of white clay.  Baker reports that North Hylton was 'sited near good beds of natural clay'.    However, the local clay was brown and coarse.  One competitive advantage for the Sunderland potteries was being able to use white clay from Devon and Cornwall, sent back as ballast in returning coal ships.  The centre and right images below perhaps show small chunks of kiln wall with jewellike deposits of cobalt blue glaze.