What is a sand struck brick, what is a water struck brick?
A sand struck brick refers to the moulding process in which the brick mould is lightly dusted with a fine sand as the releasing agent. This is a dry moulding technique and results in the preservation of the compression creasing (elephant skin texture) on the face of the brick. In Australia the term sandstock is used to describe a sand struck brick, but don't be confused by mass produced bricks using the term sandstock, a mass produced extruded brick can never be a sand struck or sandstock brick.
In contrast to sand struck moulding, when water is used to line the mould it is a water struck brick. This lubrication process results in a smoother textural patina. Both sand struck and water struck textures have never been successfully reproduced via mass production techniques.
Comparison between a sand struck or sandstock brick (left), and a water struck brick (right). These textures can not be reproduced via mass production techniques. In particular, many bricks are advertised as sandstocks, however, to be a sandstock the brick must be dry moulded with the mould dusted with sand. Its easy to tell if the brick is a real sandstock, if it has elephant skin creasing, it is a sandstock, if it doesn't its an imitation.
So what's a frog?
No we are not talking about green pond creatures, a frog is simply the indentation on the top surface of a solid core brick. There are lots of reasons for having a frog, it makes the brick lighter, uses less clay to make the brick, and makes the bond between brick courses stronger.
A soldier brick is a brick laid vertically (or near vertical) with its long narrow side exposed. Soldier courses are generally used as decorative brickwork features above windows.
Similar to a soldier brick, its is a brick laid vertically (or near vertical) with its long broad side exposed.
A brick laid flat with its long narrow side exposed, this exposed face is called the stretcher face, bricks are made so that the stretcher is the good looking part of the brick.
This is the narrowest face of the brick, similar to the stretcher face, it is designed to be a good looking face of a brick that can be exposed.
Blue headers are made by heating the header face-off the brick to a higher temperature to the rest of the brick (clinkering the header face). During this process the header takes on a black/bluish appearance. Blue headers where used to add colour variation within walls and is seen in heritage buildings. The use of blue headers in Australian was/is rare.
Another brick term often misunderstood, but a clinker brick is a brick fired at very high temperatures so that the brick starts to become vitrified (glassy). Clinkers are generally very hard and take on a dark red/purple colour and can be slightly glassy in appearance. Due to the over heating, they are often an irregular shape and make a metallic sound when struck together.