My second attempt on the wheel resulted in two small cups, which seem to be sitting at an odd spot between cups and small bowls, they seem to be lopsided and thick at the base.
The cups were so lopsided I decided to finish the first two by hand (the middle and far right cups below), carving down the exterior walls with a parring knife, removing excess clay from the thick walls. Partially burnishing one and slip coating the other with the natural clay from Windsor.
After taking a night to mull it over I set to work trying to figure out why the vessels were forming so lopsided. Was it the home made wheel? something miss aligned or of kilter? was it my inexperience showing? was I holding my hands the wrong way? too much water or too little? It turned out it was none of these. The wonky-ness was coming from the uneven deck! A quick check with a spirit level and a couple of chocks of wood to correct the level and the wonky-ness was fixed! (well, greatly reduced, lets stock the rest up to inexperience, shall we)
The fist ceramic phase is the Carinated Bowls beginning around 4000 BCE, Often identified by their round bases which continues into the Neolithic.
Late Palaeolithic – Early Neolithic Carinated Bowl Cord Impressions, Replica from Suffolk
Neolithic
Ceramic phases of the Neolithic include Mortlake Bowls, Unstan Ware, Abingdon Ware Windmill Hill Ware and Grooved Ware, which arises in the 3rd millennium BCE, this style has flat bottomed pots possibly originating in Orkney and found in places like Durrington Walls and Avebury during the first phase of building at Stonehenge.
Groove Ware Replica from Avebury
Mortlake Bowls Replica from Peterburough
Bronze Age
The Bronze Age hails the rise of the well known Beaker wear and the Beaker culture often associated with Salisbury Plain from around 2500 BCE, bridging the gap between the Neolithic and the Bronze Age.
Early to middle Bronze Age sees an increase in decoration, mainly on smaller pots often referred to as accessory vessels, incense cups or pygmy cups whose use and function is largely unknown. Late Bronze Age sees very large pots, such as collared urns.
Collared Urn and Accessory Vessel, Replicas from Cheshire
Beakers Replica from Salisbury
Beakers from West Kent and Roundway Barrows. Stonehenge Fenestrated and Grape Cup Replica Group
Aldbourne Incense Cup Replica
Iron Age
The end of the Bronze Age to the early Iron Age sees a decline in quality and variation. Areas of Northern Britain in particular seem to abandon the use of clay entirely. Southern Britain benefits from continental influences and the import of fine wheel made vessels from Gaul.
Any ceramics pre-roman invasion in 43 CE are all hand formed and open fired (Romans introduced kilns). Open firing gets pots to between 600- 800 ºC. The resulting pottery is useable but fragile.
Iron Age Replica from Southern BritainIron Age Replica from Southern Britain
Notes from the first time throwing store bought clay on the home made wheel. The first vessel was attempting to be a bowl but the side began to blow, this was rescued by turning the broken rim into a spout, creating an oil lamp like vessel.
Things I learnt:
The bought clay formes vessels much more easily
Wedging is super important and may simply work better with store bought clay potentially due to the purity and consistency of the particles
Spin the wheel when cutting vessels off
Walls blow out of bowls, may need less water, more speed, better posture or different hand movements
Things I need to learn:
Postures and hand motions/ brace positions for throwing
To attempt throwing natural clay I collected sandy clay, plastic clay and a sandy plastic clay from natural deposits from the northern slope of the Windsor bridge (Hawksbury River) at a depth of around 2 meters. The natural clay in this area is a banded orange yellow ball clay and the deposit showed no sign of bioturbation (organic or animal disturbance) which indicates a clean, undisturbed, clay deposit.
Plastic
Sandy
Sandy Plastic Combination
Firstly I mixed the three clays in a bucket of water at a ratio of 1:1 and left over night
The slush was filtered through a screen to remove any organic material which there was very little of, and to neatly mix the three clays together. Large clumps of plastic clay would not break down, these I left on the screen to dry.
Warning: I had to protect the drying clay from the chooks, believe it or not, they will eat clay clumps!
Clay slurry being carefully watched
The contents of the bucket was allowed to settle over the next week, allowing the excess water to be ladled off the top. This process imitates the natural process of clay setting on a river bed.
Silty sand was collected from the yard and sieved through a piece of hessian to remove rocks and large particles and used as temper (grog). The temper was added to the plastic clay from the sieve frame.
Mixing Temper and Plastic Clay
Wedging to work the clay into a single homogenous body between the temper and the plastic components of the naturally sourced clay was successful in creating a clean clay matrix ready for throwing, similar to store bought clay.
Success!
I attempted to throw this clay on the pottery wheel and managed to work the clay into a small vessel before oversaturation, this particular make up seems to be slightly too absorbent, there may also be something off kilter with the wheel, will need to practice with store bought clay to further understand the variables between the clay body and the wheel itself.
Reflection:
In hindsight natural clay creates a lot of torque, the features tear them selves apart as the wheel turns. This could be because the particles are too large, temper is poorly mixed or in the wrong ratio. There may also be an issue with the wheel, as this is the first time using the home made wheel.
The slush was further mixed by hand an kept to be used as a slip on future projects, it offers a beautiful yellow pigment.
The remaining natural clay has been put aside until further practice can be undertaken with store bought clay, and this will be revisited in future
Amendment:
There was a issue with the wheel, it was sitting on an unlevel surface, once this was corrected the rate of successful vessels became much higher.
You can either dig a pit directly into the ground, or build an artificial mound which is considered more stable rather than natural variations in the soil which can affect temperature retention.
The smaller the hole the better
Optional insulation at base and sides with cinder blocks, rocks, cement or clay
2: Stacking
On packed earthen base or alternative foundation as mentioned above, stack dried green ware
Consider the distribution of the coals as they fall
Do not have pieces touching, as this may encourage breakage
3: Fire Fuel
Fill the spaces under, around and on top of pieces with punk or kindling (wood shavings are ideal) this will make the firing more even
Build a fire over the top, so the coals can drop down into the pit. Continue until pottery is completely covered by coals.
4: Cooling
Cooling is where most breakages happen due to contraction
Can take 12 hours or so
Remove carefully once completely cool
Notes and Alternatives:
Make sure the pieces are completely dry before firing, if they are cool against your cheek they may need more drying
Build the fire in the pit and build up embers before placing clay pieces over top on a rack, some suggest building up and burning down this internal fire three times to heat the walls
Wood shavings should be damp, so they smoke and slowly increase in heat rather than burning rapidly, should smoke for a few hours
Let cool overnight, remove coals above, allow to continue cooling till clay is cold
Excavate SLOWLY
Unless glazed in some way these pieces will not be water tight (Bisque only) as with traditional kiln firing
Need to read further to see if a second salt firing or slip may make bisque ware fireproof
Notes from Native American art ceramicists Cher Shaffer
Several materials are referred to as clay. General properties for the classification of clay may include plasticity, staining of the hands, absorption of water before or after firing, shrinkage or reduction as water is removed and the reaction to heat. Each different clay is composed of different amounts of minerals which determines the characteristics of the resulting pottery. Raw material differs regionally, and mixing clay bodies from different areas is common to create a mixed matrix.
Kanolin: Originating in China, used for porcelain production. Also referred to as china clay.
Ball Clay: Extremely plastic, fine grained sediment clay. Small amounts may be added to Kanolin to increase plasticity.
Fire Clay: Slightly lower fluxes than kanolin. Increased firing temperature. May be added to other clays for stoneware type bodies.
Stone Ware Clay: Between fire and ball clay. Fine grain yet fire resistant.
Common Red Clay/ Shale Clay: The pigment of this clay comes from ferric oxide impurities. good for bricks. Not typically used for clay, except for certain deposits.
Bentonite: Extremely plastic, can be added to short clay to increase plasticity.
More than one clay body is often the recommendation, for throwing clay must:
Highly plastic and flexible
low absorbance
strong (coarser particles ie fire clay, grog* or temper)
Ball clay generally meets these stipulations
*Grog or temper is usually clay that has been fired then ground up and added to fresh clay, however the term also extends to anything which adds ‘grit’ or larger particles to the clay body ie sand, or paper in the case of Kanolin. General rule of thumb for grog to clay is 8% – 10% of clay body.
Collecting and Processing
Locate:
Commercial clay is mined from high grade sources
Working with machinery allows me to reach similar natural clay bed depths, which is a purer deposit than that on the surface of mud banks
To test clay composition take a wet sample and roll it into a sausage, bend the roll into a ‘C’. If it stains your fingers and cracks it is silt, if it is buttery and can form a ‘C’ it is clay
Wet Process:
To remove foreign materials, which can cause cracking or explosion due to variants in firing temperature and cavities caused by organics.
Mix clay and water in bucket until completely dispersed and thin slurry
Pour your slurry through a sieve or cloth
Let sit for a day or two. The clay will settle and allow you to pour off access water
You can now allow the rest of the water to evaporate off or you can strain the water through a bed sheet or something fine enough to keep the clay out.
Dry processing is also an option but much less successful
Temper and Clay Bodies:
Use sand, crushed shell, or old ceramics to lower the rate of expansion and reduce cracking
Continuation of the Udal excavations lead by Ian Crawford (1963-1976 and 1978-1982). The Udal site contains superimposed settlements from the Iron Age to the Post Medieval period. The site boasts over ten meters of diagnostic stratigraphy with hand made pottery found at all levels, excavation revealed 150,000 pottery shards, which due to low funding was recorded by a single person.
Archaeologists at work in Udal, 1981
1st Strat of Occupation – Iron Age
Decorative “Wheelhouse” pottery sherds
Very similar to a’Cheardach Mhor and Kilpheder
Decorative fillets, incised, applique etc
2nd Strat of Occupation – Dark Ages
Cellular homes, slab lined central hearths
2 meters of deposit
Decorative bone pins, combs, clay moulds and crucibles
Unusually rich in pottery
Carbon dating suggests 336 CE – 590 CE
Dark age ended by Viking raids and settlement 598 CE – 815 CE
3rd Strat of Occupation – Viking Age
Strat levels X, IXc, IXb
Stone buildings, rectangle forms. Slab lined central hearth.
Final level (IXb) is a dense burn layer, suggesting the destruction of settlement.
50+ bone combs, large crucibles, and a change in pottery
Viking arrival is sudden, possibly violent, mid 9th C
Level IXc is densely occupied Norse phase,
Clay platters
4th Strat of Occupation – Medieval
Complete rebuild, new house style post IXb destruction
Craggan, also referred to as ‘corgans’, ‘croganans’ or ‘cragains’ come from the gallic word for jug or jar. They often take the form of globular vessels and are a great example of prehistoric technology and tradition used in Tiree, Skye and Lewis (Hebrides) up to the mid 19th C for food storage and cooking.
They are traditionally made by women from natural clay, which would have the larger rocks removed but impurities such as sand and organics were often left in the natural clay. These vessels were completely hand formed unless the neck was too narrow for the hand, in which case a curved stick was used to form the insides. After forming the vessels would be left to stand for a day of drying, then fired in a cooking fire built up with peat. As the clay was fired a pint or so of milk was slowly poured into and over the vessel to make it less porous.
Dr. A. Mitchell ‘The past in the present – What is civilisation?’ p. 26-28
Craggan from Barvas
The ancient technique meets modernity in Barvas Ware, which comes from the small town of Bravas in Lewis, Hebrides. Made in the craggan tradition from the mid 19th C till the 1930’s the vessels themselves imitate factory made china tea sets, still produced by women with the low fired white finish of a milk ‘glaze’. Given the interest of the tourist dollar from mainlanders flowing the regular ferry service of the 1850’s Bravas wear became a commodity and was available for order in Edinburgh and London by the 1890’s in a form of primitive mock ‘Staffordshire Ware’
The Hebrides off the west coast of Scotland are universally rich in ceramics, especially the Udal, which is a major settlement site, excavated by I.A Crawford. The finds suggest occupation from 400 CE-1100 CE (Dark ages 500 -1000 CE, Viking 800-1066 CE) with typological similarities through Northern Ireland and the Faroe Islands which developed from Iron Age ceramics.
Chapter 1
The Hebrides are divided between the northern and southern Hebrides, which were never occupied by the Romans
Post Viking age Scandinavian influence continued in the Hebrides, Orkney and Shetland. Political alliance to the Norwegian crown till middle medieval period
Hebrides assemblages differ greatly from Scottish assemblages. increased quantity of pottery post bronze age. Iron Age to Medieval Period pottery in Scotland is scares aside from heavily gritted bucket forms
Hebrides are rich in pottery, decorated and plain. The decorative items are more easily dated
The ceramic rich zone stretches from Tiree to North Lewis and includes Skye
Hand made pottery continues in the Hebrides (Skye) until the mid 19th century
1st modern site report and pottery analysis under Sir Lindsey Scotti in 1948 dates assemblages to the 1st century of the Christian era. Pre 1948 all dating was done by visual motive and typology similarity.
Alison Young 1953 reaffirmed the basic sequence of occupation based on ceramics of Udall. (Young, p. 157-158). According to Young there was a wheelhouse a’Cheardach Mhor in south Udal, with an occupation sequence running from the 2nd century CE to imported wares in the 8th century CE with local ceramics ceasing in the 7th century CE
Decorated iron age ceramics, then the site was abandoned. Incised and pin stamped decoration on ‘weak’ rim and profile vessels, pre 1st/2nd century CE. Progress into raised rims and angular profiles, decorations include cordons, arcaded and fluted sections.
Simpler decorated pottery. Incised decoration declines, sparse decoration. Some vessels have flared rims and irregular cordon decoration in the iron age tradition.
Coarse plain pottery. 500 CE approx. ends before the arrival of Norse influence.
Imported pottery and Steatite
Youngs chronology challenged by her contemporary Evan Mackie, who utilised some of the early radio carbon dating technology to correct her sequence. Although most of her sequence turned out to be relatively correct, although based on stylistic similarity
Hand made pottery continued to be made there until the middle of the 19th C. Narrow mouthed, globular pots of various sizes were in general use as containers and for cooking, as well as churning during many centuries after wheel-turned glazed ware was being used in many parts of Scotland. – Callander 1921 p.129
Hand made in this context is also referred to as Craggans, which is a gallic word for earthen jug or jar
Viking age Norway is virtually a-ceramic
Breachacha Castle excavation: no wheel turned pottery till the end of the 16th C. Deposit dominated by coarse hand made craggans
Pouch or bag shapes, upright flared rims, stab mark or slash line decorations in the late medieval assemblage
Southern Hebrides and western Scottish mainland are low in dark ages pottery, despite being the heartland of early Scottish kingdom of Dalriada. Settled from the North of Ireland in 500 CE
Dates are disputed for the Souterrain wear from Ireland, potentially 6th C or Viking age, common trait of Souterrain wear is the impression of grass on the bases, most likely to prevent the vessel sticking to surfaces as they dried. These pieces are also tempered with grass.
Wooden vessels were probably preferred over ceramic. alternately a lack of evidence may indicate a genuinely sparse population in the North Hebrides during the Dark Ages pre Norse invasion
Udal is the only verifiably Viking age/Dark Ages site in North Hebrides as of 1983
Crawford describes Udal Dark Ages pottery as low quality, ring built, tongue and grove ware in the shape of ‘flower pots’
Crawford describes Udal Viking Ware as large flat grass marked platters
Other Sites of potential interest mentioned in the above text
Orkney
Balevullin site of Tiree
Dun Mor Vaul of Tiree
Breachacha Castle on Coll
Don Culer on Barra
a’Cheardach Mor on South Uist
Other scholars of potential interest mentioned in the above text
Mackie 1974
Hope-Taylor 1977
Young 1953
MacLennan 1925
Leathbridge 1950
Alcock 1971
Crawford 1974
Callender 1921
– Alan Macrae Lane, PHD, ‘Dark-Age and Viking-Age Pottery in the Hebrides, with special refferance to the Udal, North Uist’, University of London, 1983
Hit The Clay 