What is a brick mould?
A brick mould (Dutch: vormbak) is an elongated mould with a base, divided into compartments, in which clay is formed into unfired bricks. The still wet, unfired bricks are called green bricks (Dutch: vormelingen). After drying, they are fired in a kiln.
Mould frame and brick mould
The oldest method of moulding used a mould frame (Dutch: vormraam): a frame without a base. The green bricks were turned out onto a loose board and taken to the drying area. Later the mould frame was largely superseded by the brick mould, which has a base. This makes the green bricks easier to move. The base can also have a relief, so that a mortar groove, name or mark is formed in the flat face of the brick.
How it works
- The mould is sprinkled with sand, so that the clay does not stick to it.
- A ball of clay is thrown into each compartment and pressed in. Throwing the clay makes it fill the corners properly.
- The top is struck off.
- The mould is turned over and the green brick drops out.
This is now rarely done by hand, mainly for restorations where small numbers are needed that cannot be made by machine. You can recognise genuine handmade bricks by their irregular surface with creases and folds.
In the machine moulding method, a press pushes the clay into the sanded moulds and the top is struck off mechanically. The result is a sand-faced moulded brick (Dutch: vormbaksteen): crisp in shape, sanded on five faces and with one struck face.
In practice
Knowing how a brick has been formed helps you choose a suitable brick for repair or extension: a handmade brick, a moulded brick and an extruded brick look clearly different in a facade.
Related terms
- Sand-faced moulded brick (vormbaksteen)
- Handmade brick
- Brick
- Clay
- Extrusion
- Ring kiln
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