We’ve been using bricks in all kinds of constructions. Be it large commercial buildings or humble homes, the quality of bricks is a primary factor to consider in the overall quality of construction. But what makes bricks good or bad? How are good quality bricks manufactured? These are some questions we hardly ask. Yes, agreed that the people who are building your homes and offices know what they need to know. But it is always best to be aware of what goes into constructing your home.
Basic knowledge of how bricks are manufactured will give more insight into the process and help you have a better idea as to whether the bricks being used in your construction project are good enough.
So, here’s everything you need to know about the brick manufacturing process, step-by-step.
Table of Contents
Essential Steps Of The Brick Manufacturing Process
The brick manufacturing process involves several steps, starting from the preparation of the clay to obtaining the final product from the kiln. Bricks are one of the oldest construction materials, and being so durable, they are still being used in modern-day constructions.
Though we have all kinds of bricks being available for construction today, the basic process of manufacturing bricks has not changed much from the older days. The technology has, however, refined, and the quality of bricks has improved tremendously.
Here are the essential steps involved in brick manufacturing:
Step 1. Preparation Of Raw Materials
The first step in brick manufacturing is the preparation of the raw material, which is clay in this case. A lot depends on the type of clay used in brick manufacturing, so the right kind of clay must be used to impart quality to the bricks. Manufacturers first need to find the right sites to excavate high-quality clay for the bricks.
Once the site is selected, the topsoil needs to be removed. The top layer of the soil may contain dirt and impurities which cannot go into the bricks. So about 200 mm of soil from the top layer is discarded.
Digging, Spreading And Cleaning
After this, the pure clay underneath is dug out and laid on plain ground. Any stones, plant matter or other material that may be present are cleaned. The clay is then washed and screened to give lumps of pure clay, which are crushed to powder form.
The soil is then exposed to the atmosphere for a while, allowing it to soften. This step imparts strength to the clay. It usually takes a few weeks for weathering to be complete.
Blending and Tempering
The weathered clay is then blended with sandy or calcareous soil to impart more strength. Other ingredients may also be added to impart a different colour or additional properties to the bricks. The mixture is blended well by hand. The blended clay is then mixed uniformly with water and kneaded to make it firm and impart a homogeneous texture.
Step 2. Moulding Of The Bricks
The next step is giving shape to the bricks. Generally, bricks are made in standard sizes, so manufacturers need to take care that they meet these standard requirements. Bricks may be hand moulded for small scale production. For large batches, though, they are usually machine moulded.
In hand moulding, wooden or steel moulds are used. The top of the moulds is open. The mould is dipped in water, and the clay is put into the mould, pressing it to fill in all the corners and crevices. Extra clay is removed, and the surface is levelled out. The mould is then lifted, leaving the raw behind.
Hand moulding can be done on the ground (ground moulding) or a table (table moulding)
In machine moulding, there are two methods, namely the plastic method and the dry method. In the plastic method, the tempered clay is placed in the machine, extruded into a beam and cut into bricks by a wire frame. These bricks are called wire-cut bricks.
In the dry method, hardened clay is put into the machine. It is powdered and mixed with a small amount of water in the machine. The thick plastic paste created is then moulded and pressed by the machine to create bricks. These are known as pressed bricks.
Step 3. Drying Of The Bricks
In the next stage, bricks have to be dried before they can be sent to the kiln. You may be wondering why moulded bricks cannot go into the kiln directly. That is because putting them in the kiln right after moulding may cause the bricks to crack or become brittle.
The drying can be done naturally or artificially. In natural drying, the bricks are arranged in uniform columns that allow air circulation, letting the bricks dry for 8 to 10 days. In artificial drying, large drying furnaces are used to dry bricks at a large scale.
Step 4. Burning Of The Bricks
The final step in the manufacturing process is the burning of dried bricks. This can be done in an open kiln, an intermittent kiln or a continuous kiln. When burning the bricks, an optimum temperature has to be maintained inside the kiln. Temperatures above 1,300 degrees Celsius can damage the bricks.
Open kilns produce a slightly lower quality of bricks compared to intermittent or continuous kilns.
Understanding the brick manufacturing process gives you more clarity of how these bricks you are using for construction are produced and what kind of bricks will have better quality. All brick manufacturers use the same basic steps when manufacturing high-quality bricks for your use. As long as you are getting your bricks from reliable brick manufacturers in Australia, you can rest assured that each of these steps has been followed thoroughly.