Earlier today we looked at concrete blocks, now we’ll look at the traditional clay brick.
Clay bricks are a popular building material used to make walls and other elements in construction. Bricks are produced in numerous classes, types, materials, and sizes. Two basic categories of bricks are fired and non-fired bricks (there is also another type called chemically set). Fired bricks are one of the longest-lasting and strongest building materials. In South Africa the most common house brick size is 222 × 106 × 73 mm.
How bricks are manufactured
The three basic types of brick are un-fired, fired, and chemically set bricks. Each type is manufactured differently.
Fired bricks are burned in a kiln which makes them durable. Modern, fired, clay bricks are formed in one of three processes – soft mud, dry press, or extruded.
Unfired bricks, also known as mudbricks, are made from a wet, clay-containing soil mixed with straw or similar binders. They are air/sun-dried until ready for use.
Chemically set bricks
Chemically set bricks are not fired but may have the curing process accelerated by the application of heat and pressure in an autoclave.
The most common way to manufacture commercial bricks is the fire brick method, which is why I mentioned that a concrete block business is cheaper to start as the machinery cost is cheaper and it is cheaper to source the cement, sand and stone than it is to get clay (unless you are close to a cheap source of clay).
Fired bricks are burned in a kiln which makes them durable, fired clay bricks are formed in one of three processes – soft mud, dry press, or extruded. Either the extruded or soft mud method is the most common, since they are the most economical.
Wikipedia explains the shaping methods:
Three main methods are used for shaping the raw materials into bricks to be fired:
Molded bricks – These bricks start with raw clay, preferably in a mix with 25–30% sand to reduce shrinkage. The clay is first ground and mixed with water to the desired consistency. The clay is then pressed into steel moulds with a hydraulic press. The shaped clay is then fired (“burned”) at 900–1000 °C to achieve strength.
Dry-pressed bricks – The dry-press method is similar to the soft-mud moulded method, but starts with a much thicker clay mix, so it forms more accurate, sharper-edged bricks. The greater force in pressing and the longer burn make this method more expensive.
Extruded bricks – For extruded bricks the clay is mixed with 10–15% water (stiff extrusion) or 20–25% water (soft extrusion) in a pugmill. This mixture is forced through a die to create a long cable of material of the desired width and depth. This mass is then cut into bricks of the desired length by a wall of wires. Most structural bricks are made by this method as it produces hard, dense bricks, and suitable dies can produce perforations as well. The introduction of such holes reduces the volume of clay needed, and hence the cost. Hollow bricks are lighter and easier to handle, and have different thermal properties from solid bricks. The cut bricks are hardened by drying for 20 to 40 hours at 50 to 150 °C before being fired. The heat for drying is often waste heat from the kiln.
Factory tour of a clay brick manufacturer
Bob Vila tours the Redland Brick plant in East Windsor Hill, Connecticut.
As you can see you need a source of the raw materials, the two most important is clay and sand (often silica sand). The bricks often have lime, ash, and organic matter added, which accelerates the burning process.
Using a manual machine
The second cheaper option to get started is to use a manual hand machine, build your own kiln and make a few thousand bricks a day, but it will be a small business and only you can decide whether it will be worth your while. Now as I mentioned on the concrete block page you can try making a more niche block there I mentioned an interlocking block (aka Stumbelblocs), in this case you can try Hydraform sand/soil cement blocks which uses 10% cement, but their machines are not affordable for small business owners (the cheapest secondhand one I saw on Gumtree was R60 000 – and that was their smallest, lowest capacity machine. Their medium capacity 3000 brick a day machine costs R100 000 secondhand).
If you are interested in a business like this but don’t like the hard labour you can look at starting a pottery business making different tableware.
Can you make clay bricks without machines?
Yes you can, and in some African countries it is common, but in South Africa which is highly industrialised you will be up against competition that can make bricks cheaper and faster. Coupled with South Africa’s higher cost of living compared to other African countries, making bricks this way is not economical and may not be a feasible business. Maybe if you live in a rural area but not in a city. In Cape Town you could make clay bricks manually night and day and won’t even be able to afford a parking bay.
This is also not a business that can be grown from here to the point in the factory video as after you have fed yourself and your family there won’t be any profits left to reinvest into the business. If you don’t have capital, you are probably better off starting a business that requires less to start like making briquettes or manufacturing generic perfume. In an ideal country you could start a non mechanised brick operation, make it profitable and access development capital to mechanise your operation and reward your initiative but in South Africa the enterprise development institutions are in such disarray and riddled with incompetence and corruption it is a pipe dream.
If you are interested in this business on a much smaller scale you can make miniature building materials as toys for dollhouses etc.
|Equipment||Brick making machinery|
|Related||Start a Сoncrete Block Making Business|
|Industry||Building & Construction|