Chicken or the egg: which came first? As a circular argument it’s one of the most enduring, and many would say, pointless ways to spend valuable thinking time. With a little imagination, however, we could apply such a conundrum to explore the push-pull factors governing so-called market forces. Is it new manufacturing technology that paves the way for new products, or is it the consumer’s appetite for choice that keeps industrial designers and production boffins chasing their tails? An interesting thought, and seemingly far removed from this second instalment of our story on the humble brick. Or perhaps not…
Since the earliest days of the Industrial Revolution technological advances applied to manufacturing processes have helped to shape and broaden consumer tastes by making available a wider range of products. In this regard brick and tile manufacturing is no different. By the middle decades of the nineteenth century new technology was beginning to change the type and nature of bricks and floor tiles that could be produced. In our last article we explored, among other things, brick-making during early colonial times and its human impact on the lives of those involved in the industry.
To begin at the beginning, clay, the basic raw material, was manually excavated and hand-processed, a practice in Australia that continued into the early decades of the twentieth century. By about the 1830s, however, surface deposits of clay laid down over the millennia by alluvial action were rapidly being depleted. It was fortuitous for the colony that much of Sydney was located atop thick bands of shale, most notably Ashfield Shales, which formed part of the more extensive Wianamatta Group. It had earlier been discovered that when pulverised by heavy machinery, shale could be rendered into small granules. Further, when mixed with clay and a small quantity of water in the ‘pugging mill’, it could be combined to achieve the desired consistency for moulding and firing. Suitably prepared, shale makes for strong bricks far superior to sandstock which tends to crumble and lacks compressive strength. In the early days a combination of blasting (dynamite) and brawn (pick and shovel) were used to extract shale from ever-deepening pits or quarries.1 Clay and shale trucks hauled the raw materials to the surface using a combination of horses, manpower or steam winches. From the extraction and processing of clay and shale, to pressing and firing, brick manufacturing in the industrialising world was being transformed. By the turn of the century in 1900 heavy machinery had became a familiar scene in hundreds of brickyards across Australia. In fact, the popularity of brick housing in Western Australia, encouraged by government requirements for new homes to be built in brick, was exploited by the industry which claimed that the state had become the ‘brick capital’ of the nation.
At this time commercial activities such as brick and tile making were conducted by a mix of individuals, small family enterprises, government and unincorporated associations that may have had thousands of members. The latter was more prevalent in Great Britain, but all the same it created enormous legal problems in the event of litigation. In 1844 the British Parliament passed the Joint Stock Companies Act 1844 allowing incorporation under joint-stock companies. Prior to this incorporation could only be granted by royal charter or private act of parliament and was restricted to a privileged few. Under the 1844 Act a Registrar of Joint Stock Companies was established, although there was no limited liability. Company members could still be held responsible for unlimited losses incurred by the company. Ten years later, the Limited Liability Act 1855, placed business and the economy on a surer foundation, helping to increase public confidence in the honesty of business. These laws applied equally to the Australian colonies and enabled commerce and industry to grow within a legislative framework.
Stone or brick?
Before expanding our enquiry into the transformation of the industry, let us consider the social context of the decades that straddle the start of the 19th century. For the wealthy and those responsible for the construction of government buildings, the preference for sandstone was strong, due mainly to the poor quality of locally produced bricks. An element of snobbery may have been at work, which drew sustenance from the colony’s intimate ties with the Mother Country. As England’s Industrial Revolution gathered pace, brick quickly became associated with textile mills, factories and warehouses, and also with cheap dwellings for an emerging working class. In polite society brick fell out of fashion, including the distinctive red and yellow bricks hitherto prized for their appearance. Unless it was faced in stone, a man of position did not care to live in a brick house. George III may have had something to do with the sweeping distaste. Architectural historian Arthur Oswald, writing in the 1930s, relates the story of a visit by the king to:
a fine brick house near Weymouth which its owner, Mr William Morton Pitt, was accustomed to hear praised for its beauty.2 All the king said was, “Brick, Mr Pitt? Brick?” Accordingly, Mr Pitt took the hint and went to great expense of having his house faced with stone.3
Thirty years later in 1962 Alec Clifton-Taylor makes the same point, namely that ‘throughout the whole of the eighteenth century, and well into the nineteenth, stone carried with it a social cachet which attached to no other material. The Georgians, although excellent builders of brick, had a yearning for stone beyond anything that had been felt in this country [Great Britain] hitherto. For monumental public buildings, stone was considered well-nigh essential; for houses, although not essential, it was certainly highly desirable.’4
The English fascination for stone soon made the leap to New South Wales where it became established as a building material preferred for government buildings. This may help to explain the widespread use of render and stucco on the façades of the homes of well-to-do people. By mid-century the brickwork of many upper-class houses was covered with smooth-trowelled plaster on all surfaces visible to guests entering the front door. Outside only the back was left in naked brick, while inside the kitchen and rear utility rooms were left unplastered.
Even when exposed brickwork was becoming fashionable once again in the late 1840s, the result was visually uninspiring due to its poor quality.5According to social historian, Robin Boyd, this attitude towards brick continued long after machine-produced bricks with a regular arris (edge) were available. Until the late 1880s, bricks remained hidden beneath cement rendering, neatly ruled to simulate stone.6 In the final outcome, brick triumphed for economic reasons; they were inexpensive to produce and could be made just about anywhere, provided the right clay and shale was available. In fact, the cost was dramatically lower than those incurred in the quarrying, shaping and transporting of heavy blocks of stone, even for short distances.
Developments in hand moulding
There was never any question that traditional methods of hand moulding, even where hand or horse-powered machinery was used to speed the pugging process, would eventually be replaced by newer techniques. It remains an axiom that successive waves of technological innovation changed the nature of all types of manual work in the 19th and 20th century. The reality is even more pronounced today, as we witness the impact of the ‘knowledge’ economy on the labour market through a radical redefinition of the workplace. That, however, is another matter.
Steam-powered machinery blazed the trail, enabling brickmakers to better exploit the range of clays found in different parts of Australia. Advances in grinding techniques worked in favour of brick moulding which began to adopt machinery, albeit hand-operated to start with. Even the smallest of firms used the new mechanical devices. One type imported to the colony was the screw-operated John Whitehead Press, which could achieve a pressure of 15–18 tonnes. Using this machine two men could produce about 7,000 bricks per day.7 Other types of press (lever operated) could produce a daily rate of 15,000 bricks, clearly outmatching the tally of a traditional hand moulder who was hard-put to shape more than about 1,300 bricks.
In the case of the lever press, pugged clay was thrown into moulds which were recessed into the surface of the table. A lever was depressed forcing the clay into the shape of a brick or tile. By repeating the action several times, bricks were re-pressed to ensure adequate compaction of the clay, producing a brick with fine, straight edges (arris). A return mechanism forced the clay brick upwards and out of the mould. Such devices were popular with hand moulders who used them to re-press mechanically extruded green bricks, using the frog to help further compress the body of the clay.
Technology came at a price: whatever its size and sophistication brickmaking machinery was extremely expensive. According to the trade journal, The Builder, machines for moulding bricks cost approximately £1,400,8 although the economies of scale were considerable and justified the expense. It was estimated that 20,000 bricks hand produced by four gangs over a 10 hour day cost the brickmaker £3 16s, but only £1 9s when produced by machine.9 Progress towards mechanisation was still painfully slow. While moulding had been extensively mechanised in England and the USA, family-run yards in Australia, many of them short of capital, stuck with traditional methods. Today, handmade bricks continue to be manufactured, especially in developing countries such as India where family traditions have remained unchanged for generations. Sadly, this form of work organisation has more in common with serfdom for it has trapped family groups in a cycle of poverty and servile obligation.
Crushing and mixing
Gold discoveries in New South Wales and Victoria during the 1840s provided the impetus for mechanisation in the brick making process. Since gold mining required heavy machinery to break open the quartz, cashed up mining entrepreneurs were quick to import devices such as the British-made Swan’s Patent Crushing Mill. This type of crusher and the many variants spawned a variety of heavy machines that could be used to pulverise more than just quartz. Coal and shale could be reduced to suit the required purpose. For example, fragments of crushed coal (‘slack’) were used to fire furnaces and kilns. Lumps of shale were further reduced in grinding pans. With their set of heavy rollers and grinding wheels connected to a central shaft and driven by a steam engine or by horse power such mills were refinements of the original Chilean Mill used from ancient times. In its basic form this consisted of two vertical millstones on a watertight base of bedstone and turned by waterpower. The simplicity of crushing mills made them versatile and efficient with little scope for improvement.
It was only a matter of time that the larger brick manufacturers in Australia adopted this technology which gave them a commercial advantage. Over the next decade, grinding and crushing machines of every description, most of them steam-driven, were imported into Australia from both the US and Great Britain.
The evolution in brick moulding methods makes for interesting reading. From hand-thrown sandstocks of the convict period, to extruded wire cut bricks (circa 1840 onwards), thence dry-pressed bricks and finally modern extrusion technologies in the early decades of the twentieth century, the transition was long in the making and also incremental. At each step, however, quality and output improved such that the growth of city suburbs was only made possible by the vast extension of this industry.10 Many brickyards, however, continued with hand-moulding, and it was probably not until after the First World War that the majority of bricks were machine-made.
Manufacturers of specialist brickmaking machinery enjoyed a reputation for engineering excellence and included the likes of Platt Brothers, whose foundry and works in Oldham, in the industrial north of England, was employing over 20,000 men by the late 1880s. Platt Brothers built its fortune on the design and manufacture of textile machinery for thousands of mills that underpinned Britain’s vast export trade in wool and cotton cloth. It was from the workshops of this company that the ‘dry press’ brickmaking machine emerged in the mid-1870s.
Another contemporary of Platt Brothers in the manufacture of specialised brickmaking machinery was the firm of Bradley & Craven Ltd founded in 1843 by two young engineers, William Craven and Richard Bradley. Located at the town of Wakefield in the north of England, the company manufactured what was then revolutionary machinery for automating clay brick production. Their 1853 patented ‘Stiff-Plastic Brickmaking Machine’, in combination with the Hoffman continuous kiln was responsible for changes in the industry which eventually saw it shift from a hand craft to a mechanized production line. The firm’s machines were manufactured at the Westgate Common Foundry in Wakefield and sold throughout the United Kingdom as well as many overseas markets such as Australia, South Africa and Germany. The company also made steam engines, colliery winding gear and exhibited in the 1862 London International Exhibition. In 1972 Bradley & Craven amalgamated with a rival Leeds company, Thomas C. Fawcett, forming Craven Fawcett Limited, which still operates successfully today.
|Steam bricks?Prior to the introduction of the Hoffman kiln in the latter part of the nineteenth century, some manufacturers adopted the practise of ‘steaming bricks’. This was where bricks made only from dry clay and shale were subjected to a bath of pressurised steam which penetrated through to the core. This eliminated the long drying times prior to firing and also saved a great deal of space around the yard. Less water also meant correspondingly less distortion during burning, with the end result being an extremely hard brick. Moreover, by adjusting the firing time, bricks could be produced that ranged in colour from cream through reds to dark brown.There were, however, distinct limitations, not the least being that highly pressed bricks were impervious to steam. Without sufficient moisture the inside of the brick emerged from the kiln with a friable and crumbly core. This left the exterior over burnt – vitrified – with an exceptionally tough outer skin of two or three centimetres. Conversely, excessive steaming simply turned the outer skin to slush before it could burn. With the introduction of the Hoffman kiln and dry press machinery, however, steam processes gradually disappeared|
Prior to the introduction of the Hoffman kiln in the latter part of the nineteenth century, some manufacturers adopted the practise of ‘steaming bricks’. This was where bricks made only from dry clay and shale were subjected to a bath of pressurised steam which penetrated through to the core. This eliminated the long drying times prior to firing and also saved a great deal of space around the yard. Less water also meant correspondingly less distortion during burning, with the end result being an extremely hard brick. Moreover, by adjusting the firing time, bricks could be produced that ranged in colour from cream through reds to dark brown.
There were, however, distinct limitations, not the least being that highly pressed bricks were impervious to steam. Without sufficient moisture the inside of the brick emerged from the kiln with a friable and crumbly core. This left the exterior over burnt – vitrified – with an exceptionally tough outer skin of two or three centimetres. Conversely, excessive steaming simply turned the outer skin to slush before it could burn. With the introduction of the Hoffman kiln and dry press machinery, however, steam processes gradually disappeared
Methods of manufacture
There were different methods of mechanical manufacture, but three techniques were most common. Two of these involved the use of wet plastic clays, but treated it very differently: one squeezed it into a mould, the other extruded it 11like oblong toothpaste and then cut it into regular blocks. A third method also involved moulding, but used stiff plastic clays or dry shales as the raw material. Of course, the term plastic refers to the malleability of the clay and shale mix and has no association whatsoever with modern plastic materials and their innumerable variations.
But what exactly was a ‘plastic brick’? In Modern Brickmaking (1911), A.B. Searle defined plastic bricks as those:
made from clay which has been converted into a highly plastic paste, or in which the plasticity has been developed as fully as possible. All hand-made bricks and tiles are of this kind, but the term is also used in connexion with machine-made goods, particularly with loamy clays.12 The main difference between this and the stiff plastic process is the greater quantity of water added to the clay, which necessitates thorough treatment and more careful drying.13 Searle’s technical guides and handbooks were hugely influential and contain a mine of information that is still useful today.
Pressed wet plastic brick
Alluvial clay deposits were suited to the production of bricks by wet plastic methods, where clay with a water content between 15-25% had been tempered and mixed to a soft puggy consistency. The first plastic method was patented in Britain in 1825 and took several forms, although it more or less copied hand moulding techniques. Clay was deposited from a pugging machine in measured quantities into one of a number of metal moulds and subjected to pressure.
The mould moved in either a reciprocal or rotary motion to a new position, where a piston forced the brick out, and the mould was ready for refilling. Machines of this kind could produce over 10,000 bricks in a day, and their product was generally more consistent and highly finished than a hand-moulder’s. But they had the disadvantages that the clay required a lot of preparation before moulding, and being very wet, the brick was liable to damage in handling, shrank a great deal, and was slow to dry.
Extruded wirecut bricks
A more common method of manufacturing wet plastic bricks was by wirecutting, a technique invented in Britain in 1836. Wet plastic clay was extruded from the pugging machine through an aperture which produced a continuous rectangular stream of clay the dimensions of the flat side of a brick. This was cut into bricks at regular intervals by a number of wires either stretched across a frame, or forming the spokes of a rotating wheel. A single machine could produce 12,000 to 18,000 bricks in a day. This was an excellent and cheap method of forming commons, but was not suitable for face bricks.
One machine used in Australia to produce plastic bricks was a mixer-extruder which produced wire cut bricks using semi plastic clays, i.e. stiffer than that preferred by hand moulders. The process was ideal for the softer, alluvial clays of Victoria. The earliest wire cut machines, known as ‘stupids’, consisted of a clay-filled box with its hinged lid clamped down. A hand-turned rack and pinion worked a piston inside, extruding the clay through a rectangular mouthpiece of similar section to the length and breadth of a brick. The box had to be refilled after each piston stroke, although continuous extrusion was adopted after 1860. A column of clay measuring about 0.9 metres long emerged from the machine and was pushed sideways against a frame of taut wires, which sliced the clay into about ten bricks with wastage at each end. The Goodsell works at Sydney’s St Peters district mentioned in the next section made extruded wire-cut plastic shale bricks, and the plant’s circular revolving table could produce 15,000 bricks compared to an output of 1,250 a day by earlier methods. Bricks produced by this method were popular with architects because of their smooth face, although the brick had no frog. They could also be made with the same kind of plastic clay used for hand made bricks.
Despite the apparent success of the extrusion technique and its widespread use in Australia and overseas, this method had several disadvantages. Clay was insufficiently compressed during extrusion and the bricks produced were little harder than those moulded by hand. Wirecut bricks were also slow to dry, the clay being so wet that the green (unfired) bricks were dried in a shed prior to firing, resulting in shrinkage, a lack of uniformity, and a blunt arris. Further, the bricks as they came from the wire did not have frogs, and could not be impressed with the maker’s trademark. At the time wirecuts were considered to be unattractive in appearance, although to the modern eye they possess character, possibly charm.
Unsurprisingly, they were ill suited to the quality of building being erected in the boom period during the second half of the nineteenth century. To overcome some of these deficiencies extruded wire-cut bricks were usually re-pressed in a machine similar to the lever press, and ejected with a frog identifying the manufacturer.14 If re-pressing was to be performed, and to allow redistribution of the material after compression, the bricks were made shorter but deeper than the final required dimensions. Goodsell was just one of many firms that manufactured plastic shale bricks in the St Peters district. The Red Cross Steam Brickworks, which operated from 1886 to 1897 in Victoria Road, Marrickville, also specialised in white and moulded semi plastic bricks.
To remedy some of these deficiencies, wet plastic bricks were sometimes placed in an iron mould when partially dried, and subjected to very great pressure. This disguised their wire marks, gave them a highly finished appearance with sharp arrises, and could also be used to add a frog and a manufacturer’s brand. At some brickworks the bricks were returned to a machine press for the operation, while at others a portable lever press was wheeled around the hacks. This extra pressing converted commons to face bricks, but the additional handling added greatly to their production cost
Stiff plastic bricks
Meanwhile, bricks made using stiff plastic clays were found to be superior in almost every respect. This manufacturing process was originally developed in the USA in 1843.
The idea was to produce bricks that could be set direct into the kiln, obviating the need for drying. Here, the clay is forced under pressure from an auger into a mould. The rough brick is then put into a second mould for a final pressing. The texture of these bricks is rougher than a semi-plastic brick. The process, however, could only be used with harder clays and shales, and was generally not suited to surface and the more plastic clays. This was an important advance since until about the 1830s shale was considered to have had no commercial value. Brick of the stiff plastic type, made from good shale, was metallic in character15, absorbed only a small percentage of water, resisted high crushing stresses, and consequently was often used for engineering work.
During the shale grinding process, water was added to make the material sufficiently plastic to be pressed, but not so soft as for hand moulding. The bricks were then shaped in power-driven clot moulds or presses and the resulting common bricks were often of such consistency that they could be taken direct from a machine and set 20 courses high without being deformed. On the other hand, facing bricks (used to ‘face’ a house) produced by the stiff plastic process needed to be dried prior to burning. Where large quantities were required they were immediately re-pressed in a nearby machine to achieve a greater density and strength. Most of the failures in the stiff plastic process appear to have been due to attempts to shorten the process of manufacture by omitting tempering, pugging or drying. By the 1880s moulding and cutting machines had developed to a high degree of sophistication suited to particular types of plant and production.
Stiff plastic pressing was usually adopted when the large Hoffman kilns were built, and was a common brick manufacturing method for most of the twentieth century.
One pioneer producer of shale plastic bricks was the Newtown brickmaker, Frederick Goodsell, whose firm commenced manufacture in the early 1870s. Determined to capitalise on the burgeoning demand for bricks, Goodsell and his business partners established a steam brickworks on a large acreage at the junction of Edgeware Road and May Street, Newtown. In fact, he claimed to be the first manufacturer in Australia to produce bricks of the plastic type. The Sydney Morning Herald of 17 June 1870 gives an account of the opening of the plant. The article declares that ‘Messrs. Goodsell, Tye, and Hughes, who have for many years engaged in the work of brickmaking at Newtown, have recently erected a very large and complete establishment for the manufacture of common bricks, fire-bricks, drain pipes, and flooring-tiles by steam machinery upon a greatly improved principle.’
Weatherproofing qualities were improved by the simple expedient of throwing salt over bricks in the early stages of firing. Salt glazing vitrified the outer crust, but most people considered it unsightly, which helps to explain the continuing practice of painting or rendering brickwork with stucco plaster. Firing of the bricks, however, required careful supervision, and in the absence of skilled or watchful burners, poor quality bricks continued to be manufactured.
According to Smythe, a contemporary observer, bricks produced in Melbourne in 1855:
‘are light and porous, and readily yield in any direction to a slight blow. They absorb water very rapidly. When it had absorbed its maximum quantity it was easily crumbled between the fingers. Subjected to the ordinary tests the common red brick very rapidly disintegrates. Such a material is certainly not suited for building three storeys high; and yet a considerable number of houses in this city are so constructed.’16
An even simpler process was dry pressing. Dry shale was crushed to a fine powder, mixed with a minimum amount of water (10-15%), then forced into a mould and subjected to great pressure to form a brick. These bricks had the advantages of no drying shrinkage at all, and no drying time; they could be taken straight from the press to the kiln.
This development took place in the early 1880s, sparking a quantum leap in brickmaking technology in the form of the dry press machine, pioneered by English firms Bradley and Craven and the previously mentioned firm of Platt Brothers of Oldham. Within a decade dry press machines (usually referred as ‘Platts’) were established as the preferred method of brick moulding. The dry press was belt-driven, and received a steady conveyor-load of clay and shale mix from the milling sheds. This was dropped into a steel mould where enormous pressure was applied by the downward movement of a stamper, which compacted the dirt into the shape of a regular, smooth-sided and sharp-edged brick. By 1900 all major brickyards were using Platts or their equivalent to press the pulverised clay and shale. Being extremely robust they continued in use for up to 100 years provided they were regularly serviced. Until recently early 20th century era crushing machinery was in use at Bowral Bricks in New South Wales.
For many builders dry press bricks were a quantum improvement on sandstocks and wirecuts, which despite their rustic appearance, were prone to crumble and incapable of bearing loads imposed by three and four story buildings, such as warehouses and commercial premises. As the technology advanced, so did the quality and visual appeal of bricks improve. Perhaps the apogee was reached in the first two decades of the twentieth century when an extraordinary range of bricks, brick shapes and tiles were being manufactured using dry press methods. Today, few bricks are produced this way when compared to the huge number of extruded bricks that are fired in tunnel kilns. For the critics, including many architects with an interest in brick, the industry is still playing catch-up, striving to regain the look, the feel and the cachet that brick once had as a material that can never be mistaken for anything other than what it is.
Once produced in large quantities to meet consumer demand, specially shaped bricks all but disappeared during the 1970s and 1980s as suburbia advanced in monotonous regularity. They are now beginning to make a welcome return.
- As early as the 1820s the wealthy among British entrepreneurs, usually operating as unincorporated associations, were beginning to adopt steam-powered excavators.
- William Morton Pitt, MP (1754-1836) was a tireless promoter and financial supporter of work to transform Swanage into a flagship sea bathing resort. Pitt died a bankrupt in 1836, having sunk all of his fortune to promote the town as an up and coming Watering Place.
- A. Oswald, Country Houses of Dorset, Country Life Ltd, London, 1935, cited in Woodforde, pp. 86–9.
- A. Clifton-Taylor, The Pattern of English Building. Batsford, London, 1962, p. 62.
- A. Plumridge & W. Meulenkamp, Brickwork: Architecture & Design, Harry N. Abrams, New York, 1993, p. 43.
- R. Boyd, Australia’s Home: Its Origins, Builders and Occupiers, Melbourne University Press, Melbourne, 1952, p. 107.
- A.B. Searle, Modern Brickmaking, Ernest Benn, London, 1920, p. 78.
- The Builder, 1856, p. 22.
- The Builder, 1852, p. 385.
- N. Peek and C. Pratten, Working the Clays: the Brickmakers of the Ashfield District, Ashfield & District Historical Society, 1996, p. 137.
- Peter Bell, Early Bricks and Brickwork in South Australia, Department for Environment, Heritage and Aboriginal Affairs & the Corporation of the City of Adelaide, September 2008.
- Loam consists of about 40% sand, 40% silt, and 20% clay. These proportions can vary, resulting in different types of loam soils: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and loam.
- A.B. Searle, Modern Brickmaking, London, Ernest Benn, 1911, p. 120.
- M. Hammond, Bricks and Brickmaking, Shire Publications Ltd, Buckinghamshire, 2001, p. 14.
- Makers of dry-pressed bricks held that the quality of a fired brick could be determined by bringing two bricks together in the same way as a percussionist would clash cymbals. A well-made and perfectly fired brick would make a metallic, ringing sound on impact.
- R.B. Smythe, ‘On the Comparative Value and Durability of Building Materials in Use in Melbourne’, Transactions of the Philosophical Society of Victoria, Vol. 1, 1855, James Blundell, Melbourne, 1855, pp. 30, 32.