Production of Materials – Clay, Ceramic and Glass
Subject : Basic Technology
Class : Basic 9 / JSS 3
Term : 1st Term / First Term
Week 5
Topic: Production of Materials – Clay, Ceramic and Glass
Content
- Methods of making clay
- Stages in producing Ceramics and glass materials e.g. Shaping, blowing etc.
Ceramic and glass are non-metallic materials used to mould different shapes and items needed for domestic and commercial applications. The moulds are produced through different processes and methods.
Section 1: Method of Making Clay
Mud (clay is dug from the earth. This is then pounded with little water until it forms a paste (becomes malleable). The soft mud is then used to from different shapes before it solidifies.
It can be used to make different by putting the mud in moulds representing the object one intends to make. School children can use it to mould objects like pressing iron, cars, human beings, reptiles, etc.
The soft mud can also be used to make bricks by sharpening it with rectangular moulds. These moulds are removed after one or two minutes. The shape or the object formed is then put in the sun to dry.
Section 2: Stages in Producing Ceramics
Ceramics are products made from clay and dried to hardness. This follows certain stages which are:
- Clay preparation
- Clay moulding
- Firing of ceramic articles
Clay Preparation
Clay must be prepared before use in pottery. Any trace of sand is removed. The clay is mixed with water and pounded. This is to remove the air bubbles and also to make the clay more plastic so that it becomes easier to mould and shapen. If sand and air bubbles are not removed, any articles made from such clay may explode later when heated.
Clay can be used to mould different articles using the pinch pot method or the potter’s wheel. The pinch pot method is the easiest way to make a pot. A hollow is first formed with the thumb in a small ball of clay. By carefully pressing between the fingers, the wall is gradually made thinner as the form develops. The final form, containing some cracks, is then smoothed by using fingers and a small quantity of water. The pinch pot method does not involve any apparatus. However most pottery articles are made by using what is called the potter’s wheel. A potter’s wheel is a device with a rotating horizontal disc upon which clay is moulded by a potter.
Firing of Ceramic Articles
Any article just moulded from clay is soft. To harden the moulded article, it is baked in fire. One simple way of baking is by using fire wood. A more sophisticated way of heating is called a kiln. A kiln is an oven or furnace for baking finished articles. Different kilns use different fuels to produce fire for baking. Such fuels include wood, coal, oil and gas. An example is a kiln using gas. The hot air transfers heat to the finished piece as it travels through the chamber.
Decoration of Ceramic Articles
An article can be decorated before or after firing. When the clay is partially dry and somewhat hard, different patterns may be drawn on it.
Assessment
- Mention stages in producing ceramics