Staffordshire Potteries

The following is an overview of the history and techniques used in the Staffordshire Potteries for several centuries. Many past techniques described have been replaced by mechanical processes using clean technology such as electric firing.

BOTTLE KILNS OR OVENS
The Potteries skyline was once dominated by smoking bottle kilns using coal to fire the pottery wares. Some small factories had only one but other large firms had as many as twenty-five. There were up to 4,000 bottle kilns in the Staffordshire Potteries with some 2,000 still standing in the 1950s. The Clean Air Act made them obsolete but 47 still stand, all as listed buildings. No two ovens were alike for they were each built according to the builder’s or owner’s whim. They might be grouped around a yard, placed in a row or incorporated into the workshops with the chimney protruding through the roof.

Some terms describing their use are as follows:
SAGGAR - an oval or round container made of clay used to protect pottery from the flames and smoke during firing. A Saggar usually lasted for 30 to 40 firings. The wares were REARED or DOTTLED to separate them in the Saggars using PINS, SADDLES, THIMBLES or SPURS.
BUNGS - vertical stacks of Saggars that extended from the floor to the ceiling. The oven floor was usually sloping so that the heavy Bungs had to be wedged with pieces of broken Saggar to allow them to stand upright. Temperatures within the oven varied widely and it was necessary to place different wares in carefully selected locations.
SETTING – contents of the oven.
HOVEL - the outer bottle-shaped structure that acted as a chimney, rising up to seventy feet tall. The Hovel created a draught to take away the smoke and protected the oven inside from the weather.
KILN - the inner part containing the Saggars. It was a round structure with a domed roof, the CROWN, and its wall was approximately one foot thick. Iron bands known as BONTS set about twelve inches apart ran around the circular oven to strengthen it as it expanded and contracted during the firing.
CLAMMINS - a doorway built into the kiln surrounded by a stout iron frame and just large enough for a man with a Saggar on his head to pass through.
FIREMOUTHS – openings around the base of the oven to allow fires to be lit. The exact number depended on the size of the oven.
BAG - a small firebrick chimney directly above each Firemouth inside the oven. It directed flames from the fires below into the oven to protect the nearby Saggars.
FLUES – ducts under the floor of the kiln leading from each Firemouth to distribute heat throughout the interior.
WELL HOLE – an opening in the centre of the kiln floor over which Saggars with their bottoms knocked out were placed. 
PIPE BUNG - a chimney to allow the smoke to escape.
DAMPERS - flaps made from iron and firebrick which the fireman could operate by means of pulleys. Opening selected Dampers increased the draught in different sections causing the fires to burn more fiercely so as to raise the temperature. Closing the Dampers caused the temperature to be kept steady or lowered.

There were four main types of bottle ovens.
UPDRAUGHT OVEN. This was the basic type of oven. It consisted of an inner chamber with a domed roof containing the wares. Flues lead from the Firemouths to the centre of the oven to conduct heat up through the Setting and out through the top. A large kiln could hold up to 3,500 Saggars.
DOWNDRAUGHT OVEN. This oven was developed in the early 20th century to use heat more efficiently. It was similar in shape but the draught was controlled so that heat would first rise and then be forced downwards through the Setting and out through holes in the base of the oven. Hot smoke was then sucked up through a nearby straight chimney which heated neighbouring ovens.
MUFFLE KILN. This was much smaller and was used to fire decorated ware to make their colours permanent. It did not require as high a temperature as was used for Biscuit or Glost firing. Flames did not enter the firing chamber and the oven was heated by encircling flues to protect the delicate colours.
CALCINING KILN. This was used to prepare the flint and animal bones that were added to clay to make up the material from which bone china was made. By being burnt or Calcined they became brittle and could be easily powdered.

THE WORKERS
SAGGARMAKER - a skilled man producing the finished Saggar using his thumbs to join the side and base.
SAGGARMAKERS BOTTOM KNOCKER - a young boy who made the base of the Saggar from a lump of fireclay that he then knocked into a metal ring using a wooden mallet or mawl (pronounced mow).
FRAME FILLER - a male apprentice who flattened a mass of clay to produce a rectangle that was wrapped around a drum to make the side of the Saggar.
PLACERS – men who would carry full Saggars into the oven balanced on their shoulders and heads. The weight of a full Saggar was approximately half a hundred weight. They wore rolls of old stockings wedged into the front of their caps to protect their heads. They gradually worked their way around the ovens setting the Bungs from the centre towards the Clammins until the oven was full.
FIREMAN – the worker who controlled the temperature by opening or closing Dampers.

The Saggarmaker

                                                                      The Saggarmaker's Bottom Knockers

The Placers at work

THE WARES
BISCUITWARE - all pottery after its first firing.
GLOSTWARE - ware in the process of being glazed.
HOLLOWARE - cups, bowls, jugs and vases. These were packed on a thin layer of powdered flint or silica sand on the bottom of each Saggar.
FLATWARE - dishes, plates and saucers. These were BEDDED on a layer of powdered flint or silica sand then covered with another layer of sand and flint continuing with successive layers until the Saggar was filled.

Fine china was made from combinations of China Clay or Kaolin from Cornwall, Ball Clay from Devon or Dorset, China Stone from Cornwall and Flint. Each was broken down in a BLUNGER or mixing chamber to form a liquid termed a SLIP. The four Slips were then mixed and placed in a SETTLEMENT VESSEL. Powdered animal bone might then be added to make fine Bone China. The mixture was later converted to a BODY or earthenware mix by a machine that squeezed out the water to leave thick slabs to be later taken for THROWING or MODELLING. The MODELLER would wet the clay and make a shape according to the DESIGNER and this would be fired to form a Mould or MASTER BLOCK. For complex shapes, these would be made in sections from Plaster-of-Paris. From this would be made a MASTER CASE used for WORKING MOULDS. These would last for some 30 or 40 times before they lost their shape when they would be renewed from the Master Block. To make a piece, the mixed Slip would be poured into the mould which would absorb water leaving a firm clay. Excess Slip would be drained, the piece removed from the Mould and placed on a shelf to dry after which it would be sent off for Biscuit Firing. Subsequently, the background colour would be painted on and any pattern applied using a transfer from ink on a copper plate onto special tissue paper. The piece would then be fired in the Muffle Kiln. The piece would then be dipped in a liquid glaze using ingredients for making glass including silica, alumina, and different metal oxides for pigmentation such as Iron for red and Cobalt for blue. The piece would then be sent back for Glost Firing.

FIRING THE BOTTLE KILN
On average, Updraught ovens were fired once a week. A Biscuit (first) firing took three days and a Glost (second) firing took two days. It required about fifteen tons of coal to fire one bottle oven once. Almost half the heat generated would go up the chimney as smoke. The air became terribly polluted. In Longton, the town with the greatest number of bottle ovens, it used to be said, "It was a fine day if you can see the other side of the road. When the bottle ovens were firing it was almost impossible to see your hand in front of your face”.
After placing the Bungs, the Clammins was blocked with bricks and sand and fires were lit in the Firemouths and BATTED - that is, coal was loaded onto the fires - at intervals of about four hours.
In the early stages of firing, the temperature was kept low while moisture in the ware was driven out, known as SMOKING .
After about 48 hours, a maximum temperature between 10000C and 12500C was achieved and maintained for approximately two to three hours. Fine control of the draught was achieved by altering the position of the Dampers in the Crown. The fires were then left to go out.
When the firing was over, the Clammins was broken down and the oven left to cool for about 48 hours. When it was sufficiently cool for a man to enter without being harmed by the heat, the oven was emptied or drawn. Frequently, the oven was opened early to fill an order, and the men would then go in when it was too hot protecting themselves with wet rags over their hands and faces wearing overcoats and jackets wrapped around their wrists to lift down the Saggars with padded arms.

THE POTTERIES OF STOKE-ON-TRENT
Today's city is a collection of what was once six separate towns - Burslem, Fenton, Hanley, Longton, Stoke and Tunstall. After acrimonious dispute, they finally came together as the one county borough in 1910. Their proximity to water, coal and clay as well as a large labour force combined to create the world centre for production of ceramics. There is evidence that the Romans and Saxons made pottery in the area and the earliest finds date from as far back as 2000 BC. The earlier production was for sanitary wares and utilitarian earthenware. However, master potters gradually learned the secrets for making fine white porcelain which had been a Chinese speciality. The popularity of pottery increased partly associated with the tea trade from the East Indies as did the number of factories in the Potteries. More than 200 factories were operating in the region by the end of the 19th century and more than 1,500 potters came and went during this time. The success of the potteries around Stoke had bad effects on public health. Lead poisoning from lead glazes was responsible for 'potter's rot' and there was a permanent haze and pollution throughout the area. Regulations were progressively introduced to correct these problems.

TUNSTALL. John Adams established a factory in 1787 and the family dynasty has lived on. Other famous potters include Alfred Meakin, Thomas Booth and Enoch Wedgwood. Decorative ceramic tiles are still made by H and R Johnson-Richards Tiles Ltd. It was also the birthplace of Clarice Cliff and Susie Cooper.

BURSLEM. William Adams of Burslem was recognized as the first master potter in 1617. By 1710, Burslem was well known as a pottery centre and its fame increased greatly when Josiah Wedgwood rented the Ivy House Pottery Works, Burslem from his uncles John and Thomas Wedgwood to set up a factory in 1759. Other famous potters in the town included Burgess and Leigh and Enoch Wood. The Doulton Works moved there from London in 1877.

HANLEY. Famous potters in the town included Miles Masons and Job Ridgway working in Cauldon Place later to be the site for Cauldon China. Nothing is left now of other Hanley pottery manufacturers such as New Hall, Neale & Wilson, Meigh or Brown-Westhead and Moore.

STOKE-UPON-TRENT. Famous potters located in the town have included Thomas Minton and Josiah Spode. Josiah Spode I was apprenticed to Thomas Whieldon in 1749 and Spode china later to become WT Copeland and Sons has been produced on the same site in the centre of town since 1770. Grimwades Ltd. was established in 1885. The frontage of the Minton-Hollins tile works still stands. The original factory and bottle kilns for the Falcon works where Goss china was made are still present. 

FENTON. The town’s greatest manufacturer was Thomas Whieldon, the most pivotal figure of 18th century pottery. Other distinguished Fenton potters include Miles Mason and his son Charles.

LONGTON. The first Staffordshire pottery was made here by William Littler in 1742. The firm of Collingwood Bros. was established in about 1780. Herbert Colclough started manufacture in 1890. Of the older pottery firms only Aynsley survives, but many china firms such as Paragon and Royal Albert still dominate the town,

Reference: thepotteries.org