In large-scale pottery manufacture years ago, the furnaces (called bottle kilns from their shape) were heated by coal or coke furnaces. Flames, ashes and corrosive gases would have damaged the pottery if it wasn’t protected by being put into protective boxes called saggars, a word that seems to be a contraction of safeguard.
They were hollow squat cylinders with flat tops and bottoms so they could be stacked in the kiln, often in piles 30 feet high or more. Saggars were made from a type of fireclay that was mixed with a proportion of ground-up reused saggar called grog; they only lasted for about 40 firings, so every large works had its own saggar-makers:
Cups, saucers or even lavatory bowls or sinks are placed in saggars to protect them from dirt and slag. The saggars are placed in a pile known as a bung in a kiln as big as a living room, only higher. The top flat saggar is called a hiller. The saggars are made to match the shape of the porcelain inside. A saggar can hold about 15-20 plates. Saggars are still used in the industry for specialist items such as insulators for power stations in the electro-porcelain industry but the Clean Air Acts closed down coal-fuelled ovens.
The People, 23 Feb. 1997.
The speaker was Kevin Millward, at the time described as “probably Britain’s last remaining saggar maker’s bottom knocker”. His job was to act as assistant to the saggar-maker, making the heavy flat bottoms of the saggars, beating the fireclay into shape inside an iron hoop using a mallet called a mawl (pronounced “maw” in Staffordshire).
These and related jobs — such as the batter-outs who beat out the strips of clay for the sides of the saggars — vanished when kilns began to be fired by gas or electricity so that protective saggars weren’t needed.