Glossary P-Z

Here, in this glossary, is an alphabetical list of terms used in the firing of a traditional Potteries Bottle Oven. For definitions of more general terms used in a traditional Potbank click here>

The Last Bottle Oven Firing in The Potteries 1978 : GLOSSARY

These words have been collected during a lifetime in potbanks. Some are specific to a particular factory, others are more general. Some vary from potbank to potbank and from Tunstall in the north to Longton in the south. Some are technical, and some feature the very special dialect of The Potteries. Some words are being lost as potbanks close or manufacturing methods change.

P

PEELER Equipment. Tool. Similar to a punching poker.

PEEPHOLE Same as spyhole. Part of a bottle oven. Small opening just above the regulator hole above the firemouth in a bottle oven. Allows viewing of the condition of the fire in the bag (which itself can have a hole in its far side to allow viewing straight through into the oven beyond. Sometimes covered with a metal slide or a brick end.

PIECE Item of pottery ware. Flatware or holloware are known as pieces. It is unlikely, though, that a large piece of sanitaryware, a toilet, would be known as a piece.

PIGEON HOLE BOTTOM Particular type of construction of the floor of a biscuit bottle oven. The floor was constructed in such a way as to allow the hot gases from the fire mouths to penetrate deeper into the oven and thus create a more even spread of heat.

PIN Equipment. Kiln furniture. Used in cranks or sometimes called racks. Located in the upright posts (called rods) to support dipped ware prior to the glost firing. The top piece in the rack is called the crown.

Pins in a crank supporting glost plates

PINNING Process. Fixing pins in the empty holes in posts of cranks.

PINNER Occupation. Ovens department. Person who carries out the pinning process.

PINCHING Process. In saggar making.

PIP Kiln furniture.

PIPPER Occupation. Ovens department.

PIPE BUNG Part of a bottle oven. Sometimes called the well hole pipes. A chimney, made up of saggars with no base, standing in a bung over the well hole in the centre of the bottle oven. The height of the pipe bung depends on the height of the oven to the crown. Has no effect on the draught of the oven.

PLACER Occupation 1. Ovens department. A placer is the person, usually male but could be female, who places individual clay pieces or dipped biscuit pieces into saggars before they are placed (or set in) the oven for firing. If the firing was glost then he or she would also need to place wads of wad clay on the top rim of the saggar before it was taken into the oven.




PLACER Occupation 2. Ovens department. Male.  The placer is the man who fills or sets the oven with saggars containing the ware which had been placed into the saggars by the previous placer. The placer works for the cod, his boss.




Placing a bung of glost saggars. Notice the wad between each saggar Ted Locket at the Last Bottle Oven Firing
Cod Placer
Placing a bung of glost saggars. Notice the wad between each saggar
Ted Locket at the Last Bottle Oven Firing
Photo: Terry Woolliscroft Collection  Date: August 1978

PLACERS ROLL Equipment. Used by a placer.  A rolled up roll of fabric (or more usually ladies stockings) to form a doughnut shape, then tucked inside his hat to steady and help balance a saggar on his head.  Also known as a Donut

Placer's Roll or Donut
Photo:courtesy of Nerys Williams of Gladstone Pottery Museum


PLACING  Process in the ovens department. Loading the oven with saggars full of ware ready for firing.  Also known as SETTING IN

PLATE Equipment. Used in the saggar making shop. Large flat metal sheet pierced with holes of about 2" diameter. Used by the saggar maker's bottom knocker to transfer the recently made saggar bottom onto a whirler prior to the saggar maker constructing of the sides of the saggar.

Saggar Maker's Bottom Knocker holds a plate
Saggar Maker's Bottom Knocker holds a plate

PLUCKER Equipment. Used by the saggar maker. A piece of wood with bevelled edges used to flatten and shape the saggar clay to secure the saggar bottom to the sides. (Source: Alfred Clough during the Last Bottle Oven Firing 1978)

PLUCKING UP Process. During saggar making. Attaching the bottom to the sides of the saggar by manipulating the clay from which the saggar is made using a plucker.

POST Kiln furniture. An upright in a crank. Three posts are used in a crank. Also larger refractory columns used as kiln furniture to support kiln shelves.

PRICKING Ovens dept. State of flame in the firing of a coal-fired bottle oven. Could be seen through one of the spy holes in the bottle oven.

PRIMARY AIR The air which passes through the firebed in the mouth of a bottle oven to aid the burning coal.

PROP Kiln furniture. One of three uprights in a crank.

POST Kiln furniture. Part of the kiln furniture used in a bottle oven.

PUNCHING POKER Equipment. Tool. Used during the firing of a bottle oven. About 6 feet long and an inch and a half thick. Sometimes called a peeler.

PYROMETER Equipment. Device for measuring the temperature in the bottle oven or kiln.

PYROMETRIC CONE Equipment. Ovens department. Device used to gauge heatwork during the firing. The cones, often used in sets of three are positioned in a kiln with the ware to be fired. They provide a visual indication of when the ware has reached a required state of maturity, a combination of time and temperature. Thus, pyrometric cones give a temperature equivalent, they are not simple temperature-measuring devices. Sometimes called 'seger cones.'  In 1782, Josiah Wedgwood created accurately scaled pyrometric beads. This led him to be elected a fellow of the Royal Society.




PYROSCOPE Equipment. As Pyrometric cone. Or may be a Bullers Ring.  A piece of specially blended ceramic body which is designed to bend , shrink or melt at specific temperatures. These were placed in the oven prior to firing in places where they could be viewed or extracted and measured during the fire and near to the end of the firing process. The pyroscope enable the fireman to judge how well or badly the fire was proceeding.


Q


QUARTERS Part of a bottle oven. Areas within the bottle oven. The circular oven divided into four.

QUARTER DAMPERS Part of a potter's bottle oven. A substantial hinged brick and iron flap operated by iron levers and pulleys to close or open the hole in the domed roof (or crown) of the oven to control the flow of the hot combustion gases passing through the oven during firing. Four (or more depending on the size of the oven) quarter dampers were positioned equidistant around the circumference of the oven crown. Not to be mistaken with the crown damper which was the one in the top centre of the dome or crown of the oven.


Quarter damper on the crown of a bottle oven.

R

RAWNGED Dialect. A particular manoevre of the body which is un-natural and therefore causes some discomfort, and even pain in the muscles. Or the cause of a back back. Straining. PLacers sometimes suffer this.

REARING Process. Not to be confused with dottling. Placing glazed pottery ware on edges using thimbles and stilts, ready for glost firing in saggars.



REGULATOR HOLE Part of a bottle oven. Found above the hob. Used to control the amount of secondary air entering the oven through the bag. Sometimes fitted with metal (cast iron) slides otherwise loose bricks are used to cover the holes and regulated the movement of air. Above the regulator holes is the spy hole which allowed viewing into the bag.

Regulator hole with iron slider cover

REPAIR Process.  Bottle Ovens were notoriously fragile - they wore out during use. They regularly needed to be put out of use and repaired.

RIDDING Process. In the bottle oven. The thorough repair and relaying of the flues, oven bottoms, and bags in a bottle oven. A major operation which puts the oven out of use for some considerable time. Needed to be done every three years or so - depending on the work that the oven had been put to. In 1920 ridding would cost around £30. (A complete rebuild of a bottle oven, excluding the hovel, was required every 20 years)

RING Part of a bottle oven. Name of the circle of saggars as placed. 1st, 2nd, 3rd and 4th rings in the oven.

RING DAMPER Part of a bottle oven. Used in some updraught bottle oven designs. These dampers where positioned on the oven crown above the first and second rings of bungs of saggars. Extra to the crown damper and quarter dampers to give a little greater control of the draughts during firing.

RINGER Kiln furniture. Saggar with no bottom. Used in a bottle oven. Used to add height to a standard saggar. Also used to create greater packing density within the oven. For instance in glost placing using a ringer the lower half of one pot (basin) enters into the upper half of the saggar below.



ROBEY OVEN Type of bottle oven. Downdraught. Patented by C Robey in 1873.

ROLLS Part of a bottle oven. The decorative brickwork found at the top of the neck or stack of the oven. Formed by the use of bull nosed or pig nosed bricks. A typical feature used by kiln builders to create a decoration to the oven structure.

ROLOK COURSE Part of a bottle oven. The row of bricks, laid end on, to finish the courses of bricks up to hob level in the firemouth.

RUN OF KILN or RUN OF OVEN A trade term that died out in the mid 20th Century. More of a merchants description than a manufacturer's. It implies that the ware is unselected and goes more or less straight from the kiln into the crate or caskBestseconds and even thirds are packed together at one fixed price; and usually a low one.


S

S HOLE Potter's name for the ash pit underneath the firemouth in an oven. Also a Potteries dialect word. "S Hole is simply a dialect way of saying ash hole [found in coal fires in domestic premises] rather than a specifically industrial word." Many thanks to Brian Jones for this update 18 March 2016 

SADDLE Kiln furniture. Used during firing to support glost pottery in a saggar. Consists of a bar of refractory ceramic with a triangular cross section.


SAGGAR - "One of the big essentials in a successful pottery business is a good saggar" 

Hand-built kiln furniture. Sometimes SAGGER or SHRAGGER. Used during firing. An open box, in different shapes and sizes, made of  fireclay or saggar marl with added pre-fired grog and fired before use. Specifically manufactured to contain pottery during a biscuit, glost or sometimes decorating fire in a bottle oven.


The saggar protects the ware it contains from contamination by kiln combustion gases and ashes, and the action of the flames. Saggars of a particular shape and size have particular descriptive names: Ovals, Banjos, Cheese, Squares, Hillers, Skimmers.


Some say that the word saggar is derived from the word 'safeguard.'


In the "Description of The Country from thirty to forty miles around Manchester" by J AIKIN, MD published in June 1795, the word saggar is described as a corruption of the German word SCHRAGER, 'which signifies cases or suporters.'



SAGGAR HOLE Ovens department. Saggar makers' shop. Oh dear! A little derogatory don't you think?

SAGGAR MAKER Occupation. Ovens department. Very highly skilled and one of the best paid jobs on a potbank. Other well paid jobs included dish makers and firemen.

Saggar makers. Longton. 1932



SAGGAR MAKERS BOTTOM KNOCKER Occupation. Ovens department. Male. It was an occupation in the ovens department of the potbank. Usually a male - it was very heavy work. The saggar makers bottom knocker would work with the Saggar Maker himself. A bottom knocker bashes and flattens a lump of saggar marl (or fireclay, as it is known sometimes) with a mawl (pronounced mow or mau) to make the bottom of a saggar. It takes about three minutes to knock a bottom. Saggar making is no longer an occupation in the pottery industry. The art and craft of the saggar makers bottom knocker has died out. Completely. Watch the movie to see how it's done. Was done. The species is now extinct.


Film of the Saggar Maker



SAGGAR MAKING  Click here for a PDF file. A very readable and detailed study of the craft of saggar making by Paul Nicholson. 2011. “I’M NOT THE SAGGAR-MAKER, I’M THE SAGGAR-MAKER’S MATE…” SAGGAR MAKING AND BOTTOM KNOCKING IN STOKE-ON-TRENT AS A GUIDE TO EARLY SAGGAR TECHNOLOGY by  Paul T. NICHOLSON

SAGGAR MARL Type of clay. Coarse grey coloured fireclay found along with coal measures in North Staffordshire. Mixed with grog to add strength. More grog was mixed into the clay used for the bottom clay of the saggar than the side clay, as the bottom needed to be stronger. The proportion of clay to grog varied.

SAGGAR SHOP and SAGGAR HOUSE "There were in excess of 150 different processes in the making of a piece of pottery. Each person who handled each pot on its journey through the potbank had a title to go with the job that they did, Experienced people worked in shops i.e. cup shop, flat shop, casting shop, decorating shop. Not so experienced people worked in houses. Biscuit warehouse, Dipping house, Glost warehouse. Packing house and to confuse things a bit there was the Sagger shop and a Sagger House the two must never be mixed up. Again in the shop, the saggers were made, and in the house they were used."  Many thanks go to Alan Hopwood for this description. March 2016 

SAGGAR - end of life.  Once a saggar has come to the end of its useful life and can no longer be used to contain ware during firing it has to be scrapped.  Some end up in local gardens and are used to construct walling ...

A wall around a garden, made of old saggars


SCOTCH Kiln Furniture. Different shapes of fireclay or refractory bricks used as wedges to support a bung of saggars when being placed in the oven. Scotches come in various sizes - eg, wrister, two-fingers, three-fingers, knuckler.

SCUTCH Equipment. Used by a bricklayer (and in the context of the bottle oven, the builder).  Specialist design of hammer commonly used for dressing and cleaning bricks. The 'single scutch' version has a hardened square striking face at one end with a single 'comb slot' at the opposite end. Some are known as 'double-ended scutch hammers'. Scutch hammers, in conjunction with 'combs and droves' are used for cutting bricks in the same way as scutch chisels, but they are not as precise in use.


SECONDARY AIR Part of a bottle oven. During firing. Air which passes over (not through) the firebed and burning gases coming from the coal.  In a gas kiln, secondary air enters burner port around burner-tip.

SEGER CONE Equipment. Pyrometric cone. Device for measuring the heat-work imparted to pottery pieces during the bottle oven firing. Pyramid-shaped. These devices are formulated from different mineral mixtures and numbered accordingly. They are placed in a kiln so they can be viewed during firing and when a cone begins to bend it is closely monitored and the firing is terminated when it reaches a specific position.

Seger Cones to measure 'heat-work'



SET  Process. Ovens department. To place wares in a kiln.  Or, in a loaded kiln, the entire structure of shelves, furniture, and wares.

SETTING Process. Sometimes called PLACING. Loading an empty bottle oven with saggars full of ware prior to the next firing. Setting would take a couple of days of hot, strenuous and very dusty work. Stacking saggars in bungs.

SETTING The arrangement and contents of ware in the oven when it has been placed. On a potbank the setting consists of the individual pieces of ware plus the saggars and kiln furniture which supports them.

SET IN or SETTING IN The process of placing.

SETTING OUT Process. Preparing saggars prior to setting in a bottle oven.

SETTER Equipment. Kiln furniture. A type of small saggar. A piece of fired refractory material carefully shaped so that its upper surface matches the lower surface of green flatware pottery it is designed to support during firing. Mainly for firing fine china or bone china.

SETTER RING Equipment. Kiln furniture. The same as a SETTER (above) but being a ring rather than a full piece are lighter and easier to use.

SETTER Occupation. Ovens department. Similar to a placer but this time for sanitaryware - particularly fireclay. Usually working in a team of two to pick up the heavy glazed clay pieces and set them on the kiln trucks for tunnel firing. Different from a placer who works on his own handling smaller pieces.

SET IN Process. Placing a bottle oven with saggars.

SHARD also known as a  PLATE or a BAT. Equipment. Used in the saggar making shop. Large flat metal sheet pierced with holes of about 2" diameter. Used by the saggar maker's bottom knocker to transfer the recently made saggar bottom onto a whirler prior to the saggar maker constructing of the sides of the saggar.

SHORD Equipment. Saggar makers shop (saggar hole). 'Flat drying frame with holes in it. The saggar base is put onto it after being knocked out and kept on there while the sides of the saggar are added and until dry.'

SHOULDER Part of a bottle oven. The point at which the crown springs from the top of the oven's vertical sides.

SHOULDER HOLES Part of a bottle oven. Holes in the crown which are open and uncovered (unlike crown dampers) and positioned above the bags to allow the release of burnt gases.

SHRAGGER Another name for saggar. Not common though - an old word, very early. In the "Description of The Country from thirty to forty miles around Manchester" by J AIKIN, MD published in June 1795 the word saggar is a corruption of the German word SCHRAGER "which signifies cases or suporters."

SHRINKAGE 

All clays shrink. But not all clays are created equal. Different clay bodies experience different amounts of shrinkage. It depends upon the clay's particle size and on how many and what type of impurities are present in the clay body.


Shrinking during drying When a clay is wet and very pliable, it contains a great deal of water. The clay particles ride within the water, which is what makes clay plastic, or easily workable. As the clay dries the water evaporates, escaping from those spaces in between particles. The particles move closer together, resulting in the entire pot shrinking.How much the clay shrinks depends on the characteristics of the clay. Highly plastic wet clays have a very fine particle size and will shrink more. On the other hand, clays with large particles will shrink less. Also, clay bodies that include non-plastic additives, such as grog or sand, will shrink less. Shrinkage due to drying is generally between 4% and 10%.

Shrinkage during firing When clay is fired at a high enough temperature, it begins to gradually vitrify. This process of melting and fusing also compacts the clay body. The clay shrinks as the particle sizes slowly decrease as they fuse. In addition, the particles also compress into a tighter, more dense configuration within the glassy material that fills up all the nooks and crannies. The amount of shrinkage due to vitrification is very dependent on which type of clay is involved. Refractory clay bodies may have a very low degree of shrinkage at this stage, while highly vitreous clay bodies such as a high-fire porcelain may shrink up to 10%.


SIDE CLAY Type of saggar marl. Used for the sides of a saggar. The bottom of a saggar was made with saggar marl containing more grog to give it greater strength.

SILICOSIS. Disease. Potters Rot. Potters occupational lung disease caused by inhalation of crystalline silica dust. Flint dust is the worst. Marked by inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs. POTTERS ROT Pottery workers were known to die in their forties because of potter's rot. Silicosis is a lung disease caused by inhaling clay dusts containing a high proportion of free silica.

SITTER UP Occupation. The bottle oven fireman's assistant, maybe the fireman's apprentice. He kindles, cajolesguards, tenders and baits the oven while the oven fireman takes a break during the firing cycle. The sitter up will get the oven up to a high temperature after about 20 hours of firing then the fireman will take over finish off the fire completely.

SKIMMER Kiln Furniture. Part of a Bottle Oven. Different shapes of bricks used as wedges to support a bung of saggars. Also a particular shape of saggar, even lower in height than a hiller but for the same use.

SMOKE Product of burning coal. Stoke-on-Trent was once described as the smokiest city on the world - smoke being created in vast volumes when the bottle ovens were in full use. The Clean Air Act of 1952/53 started the clean up of this filthy Stoke air but it was not until 1978 when the last oven was fired in The Potteries, and this was the special event organised by The Gladstone Pottery Museum. more here>




SMOKE HOLE Part of a bottle oven. Small (3 inch square) holes in the crown of the bottle oven. Without dampers. Found equidistant between the shoulder holes and the central crown damper.

SMUT Particles of soot created during the firing process which drop gently through the air and land on your recently washed clothes! Because smuts are greasy they create a horrible black mark. Annoyingly common on firing days. Can be "the size of golf balls!"

SOAK, SOAKING TIME and SOAKING PERIOD Part of the firing process. The period when the fire has reached its top temperature and during which that temperature is maintained for a time to allow any stresses in the clay piece to release.  ALSO  During firing or cooling-ramp, the act of holding kiln at steady temperature for a period of time to allow proper formation or maturation of certain clay and glaze effects.

SOOT Pronounced in The Potteries as 'sooot' not 'sut'. Found in chimneys after a coal fire. Lots of it around in the days of coal fired bottle ovens!

SPUR Kiln furniture. Equipment. A refractory support to separate plates within the saggar during firing. Spurs leave small marks in the glazed surface.



SPY HOLE Part of a bottle oven. Small opening just above the regulator hole above the firemouth in a bottle oven. Allows viewing of the condition of the fire in the bag (which itself can have a hole in its far side to allow viewing straight through into the oven beyond.) Sometimes covered with a metal slide or a brick end, or even a bowl of lobby.

STACK The chimney of the bottle oven.

STACK OVEN Type of bottle oven. These are bottle ovens with their chimney stacks built directly from the shoulder of the crown of the oven itself. This is the form developed when a series or row of ovens are grouped together under one roof, the stacks rising through the roof of the building. These ovens were solid and compact but they tended to be more difficult to repair and took a longer time to cool down. The oven fired in The Last Bottle Oven Firing 1978 was a STACK OVEN   More here>

STICKLER Part of a bottle oven. (Sometimes, and more rarely, known as a cleat.) During the building of the oven, the bricklayer would turn a brick(s) through 90 degrees to make its short end project by half the brick's length (4.5 inches) into the interior of the oven. He did this at regular intervals and heights in the arches, between the bags. The resultant projections, called sticklers, enabled the oven placers to ensure that each bung of saggars was kept as vertical and as rigid as possible. Scotches were used between the bung and the stickler to make the bung rigid and less prone to collapse during firing.

Sticklers and scotches
Photo: Terry Woolliscroft Collection  Date: Last Bottle Oven Firing 1978


STILT Equipment. Kiln Furniture.

Stilts

STILT CLAY Material. Clay recipe in the 1820s was:
16 pail full Black Clay Slip
2 pail full Flint

STILT PRESS Equipment.  A machine in a specialist kiln furniture workshop for pressing refractory clay dust into kiln furniture.



STILT PICKER Occupation. Ovens department. Person who sots out used stilts into reusable stilts or those which need throwing away.

SUT Dialect for 'posh' soot. Found in bottle ovens here>


T

TERTIARY AIR Used during firing. In reducing kilns (Eg: for the production of blue bricks and tiles) Introduced into the firing cycle to burn up combustibles in waste gases. Reduces smoke.

THERMOCOUPLE Equipment. Part of a bottle oven or modern kiln. Electronic method of high temperature measurement. Based on tiny electric current produced at the junction of two dissimilar metals in a wire when the wire is heated.


THIMBLE Kiln furniture. Manufactured by pressing refractory clay into moulds. The conical base of one thimble fits into the open top of the thimble below so that a series, or tower, of thimbles make one upright support.  Three of these towers, in a triangular formation, create the individual supports for flatware, in a saggar, for glost firing.

"Thimbles were used during the times of bottle oven firing. During glost firing they were used to separate plates to prevent the glaze fusing them together. The plate rests on the little pointed bit to make smallest possible mark on the glaze. There were usually three sets of thimbles around a plate, held in place in the saggar by a blob of clay."  This explanation kindly supplied by Angela Lee, Manager, Gladstone Pottery Museum, October 2017.




Used thimbles showing how they slot into each other
Thimbles can only be used once.
Photo: Courtesy of Chris Morris  Date: Oct 2017

THIMBLE DIE PRESS Equipment. A machine in a specialist kiln furniture workshop for pressing refractory clay dust into thimbles.


Thimble die press


THIMBLE PICKER
 Occupation. The operative who sorts and arranges thimbles for use by glost placers.

THOB Potteries dialect word. Part of a bottle oven. The Hob. Just above the glut arch. "Put thee lobby on thob fur cape eat ot, duck."  But note that it is not where you would cook breakfast.  This was done directly on the fire, in the blazing mouth of the oven, using a British Standard No.8 shovel!

At the Last Bottle Oven Firing in The Potteries, August 1978.
Organised by Gladstone Pottery Museum, Stoke-on-Trent,
with its team of volunteers. 
Here is Les Dennis with his bacon (and, of course, oatcakes)


THOROUGH REPAIR Process. In a bottle oven. Almost a complete rebuild of the oven bottoms, ash pit and hob, bags and flues. Since production could be lost during a thorough repair then it was usually carried out at weekends.

TIEING Process. During the placing of a bottle oven. Arch bungs of saggars are 'tied' to the crown of the oven by stuffing a fired saggar between the top of the bung and the underside of the crown of the oven to secure the bung.

TILE SETTER CRANK Kiln furniture used to support tiles during glost firing.


TOPPING STICK Equipment. Used by the saggar maker when bannering. A small metal or wooden tool used to true up the rim of an unfired saggar to ensure that it lay in one true horizontal plane. Bungs of saggars in a bottle oven can reach up to 20 feet high, and should stack as close to the vertical as possible. It was therefore an important job to ensure that the rims and bottoms of freshly made saggars were perfectly flat.

A saggar maker using a topping stick to banner his saggar
A saggar maker using a topping stick to banner his saggar

TOPS The top most saggars in the bottle oven. Two men would 'draw the tops' when a recently fired bottle oven was emptied. It was extremely hot and strenuous work and they would do it in half hour stretches. Those who had drawn the tops would be let off doing any climbing on osses during the following setting (or placing) of the oven.


U

UPDRAUGHT Type of Bottle Oven. The simplest and most common type of bottle oven in the heyday of the pottery industry.


Updraught bottle oven diagram and external view
Bottle Oven - updraught.
Cross section diagram and external
drawing and photo: Terry Woolliscroft

The updraught oven consists of an inner chamber, the oven itself, with a domed roof called the crown, in which the pottery ware is placed and fired.  The oven is enclosed by an outer chamber called the hovel. The hovel acts as a chimney, taking away the products of combustion, creating draught and protecting the inside from the weather and uneven draughts. Sometimes the hovel became part of the factory workshops. Entry to the inside of the oven is through a doorway called the wicket. During firing the wicket is sealed with brickwork and daubed with clay to become the clammins. Firemouths, situated around the outside of the oven at ground level, are connected to brick flues and bags (small chimneys) on the inside of the oven. These carry the intense heat from the coal burning in the firemouths to the ware inside. The flues converge at the centre of the domed floor of the oven called the well hole. The heat rises up through the setting and then out through the top of the oven and up its chimney, or stack. At its peak the oven for the firing of biscuit ware could reach temperatures of over 1200°C. This updraught bottle oven could be used for firing both biscuit and glost ware.  More types of bottle oven here>


UPDRAUGHT STACK OVEN  - sometimes known as CONE OVEN. These BOTTLE OVENS are ovens with their chimney stacks built together. This is the form developed when a series or row of ovens are grouped together under one roof, the stacks rising through the roof of the building. These ovens are solid and compact but they tended to be more difficult to repair and took a long time to cool down.

This type of oven has its chimney stack built onto the crown of the oven.

This was the type of oven fired in The Last Bottle Oven Firing 1978

Bottle oven - updraught stack or cone oven. Cross section diagram.
Drawing and photo: Terry Woolliscroft Collection


It has no separate hovel.  These ovens are solid and compact but they tended to be more difficult to repair and took longer to cool down.

Bottle oven chimney stacks rising through the roof of the factory
Bottle oven - updraught stack oven
Bottle oven chimney stacks rising through the roof of the factory
Photo: unknown source  Date: unknown



UPDRAUGHT SKELETON BOTTLE OVEN  This design of oven became very popular in the early 20th Century because it seemed to combine all the best qualities of the different types of updraught oven. It was simple in design and construction, relatively simple to operate, easy to repair and gave satisfactory results. more here>

UVVER NUN NOVEL Potteries dialect for Oven and Hovel. A bottle oven. A kiln.


V


W

WAD Particular type of clay material used during the process. Fireclay or saggar marl. See below.





WAD BOX EquipmentDevice used for the extrusion of cylindrical lengths of fireclay, or saggar marl, wads.These were used as soft, spacer cushions between the individual saggars being placed in a bung in the bottle oven. See immediately below.

WAD CLAY Material used during the process. Rope-like strip of plastic clay. Used as a cushion between saggars when they are placed together, one on top of an other in a bung, in the oven. In addition to the effect of levelling the bung, wads also seal the uneven joint between the saggars, thus preventing smoke and fumes from the the fires coming into contact with the ware during firing. Made from fireclay or saggar marl specially formulated with its own body recipe to create wad. Contains a finer grog than saggar making clay. Wad should not crack, split or fly off during firing since it could spoil the ware (particularly glost ware). 

In 1820, the recipe was recorded as follows:   

  • 2 Barrows full Nockings from Common Slip House.  
  • 1 Barrow Full Tough Tom.

WARE BOARD EquipmentUsed in most departments of the potbank. About 6 feet long, 9 inches wide and an inch deep. Made of good quality pine. Simply a board with rounded corners to carry ware about the potbank. Carried on one shoulder and supported with one hand, requiring some balancing skill. Sometimes called a work board.

Carrying a potter's ware board


WATER SMOKING The period, during firing, where the last of the 'mechanical water' in a pottery body and glaze is released. Usually a firing will be taken to the boiling point of water and held there for the amount of time necessary to remove all the water (the 'water smoking soak'). The degree to which the drying process has removed most of the water determines soak time needed at boiling point, but also the temperature at which the water smoking soak can be conducted.

WELL Sometimes called the ashpit or the essole. The space beneath the firebars in the bottle oven's firemouth. Ashes from the burning coal above drop into the well which is then scraped out at intervals during the firing of the oven.

WELL HOLE Part of a bottle oven. The hole in the centre of the floor of a bottle oven. All the undefloor flues are connected to the well hole. During firing a pipe bung is placed over it.



WELL HOLE PIPES Part of a bottle oven, in the centre of the base of the oven. Another name for a pipe bung made with saggars with no bottom. Placed over the well hole to carry flames on hot gasses up the centre of the oven after placing and during firing.

WICKET Part of a bottle oven. The open entrance used by places and drawers to go into the oven with saggars to fill and empty it. (Sometimes incorrectly called the clammins, or clammins arch.) The open doorway to the bottle oven which is bricked up and sealed with clay at the start of the firing process.


WILKINSON OVEN Type of bottle oven. Downdraught. Patented 1890.

WRISTER Kiln Furniture. Part of a bottle oven. Particular shape of scotch which were the width of a human wrist. Excellent description for use by placers working in a team to describe exactly what is required.

XYZ