Bricks

Bricks.

Bricks vary lots in colour and size, even bricks in the same so called "batch" can vary lots.
Order enough for your job from the offset, dont expect to receive the same bricks with a follow up order.
Some fired bricks will vary by as much as 10mm in length from their friends in the same batch.

Not all bricks are suited to all applications.
Bricks have many different uses depending on their composition and make up, firing times, clay content or lack of it, etc.

Bricks that are under fired are called Chuffs/Dough Boys.
Bricks that are over fired are usually called Clinkers, (it must be the sound they make as they are usually very brittle?)
Modern bricks are burnt, old bricks were baked.
Older bricks are very very soft when compared to the modern brick.

Clay Wire Cut.

Wire cut bricks are extruded from a brick making machine in one continuous flow(maybe wrong wording) of clay, the bricks are cut from the flow of clay with an overhead wire that passes through the clay at 76 mm intervals.
Decorative finished can be applied to the face of the brick after it is extruded and before cutting.

Wire cuts usually have holes in them to aid laying and to save clay.
Holes vary from 3 to 12 per brick, it all depends on the maker and the brick machine type.

Clay Pressed

Pressed or Dry Pressed bricks are forced under high pressure into a mold, the clay is usually dry or just slightly damp.
The mold usually has a frog in it to create a depression in the bed face of the brick.
Pressed bricks are very dense in comparison to Wire Cuts.
The pic below in Frog shows a solid brick

Frog

There is divided opinion about if the frog should be laid up or down.

I prefer the frog down method myself as it speeds up laying time.
The purist insist that it is frog up as there is a better bond with the brick above due to the frog filling with mortar as you spread the bed.
That may have been true when lime mortar was in use and harder to spread than the modern cement based mortars.


The pic below shows a frog in a solid brick.

Sand Lime Bricks

Made of sand and lime and steamed in an autoclave to make them hard.
They are white when made but discolour to yellow or greenish over time.

Brick Part Names

Arris	Intersecting edge at the corner of a 90 degree angle.
Frog	Depression in a solid brick, the frog makes the brick easier to lay, solid bricks without a frog are difficult to lay as the mortar has nowhere to escape to as the brick is bedded down.
Bed Face	The bed of the brick is usually laid face down, or up, which ever way you look at it. Measures 110 x 230 mm.
Face	Usually the good side of the brick when laid in a wall. Measures 76 x 230 mm.
Header Face	The small end of the brick. Measures 76 x 110 mm

Faults

• Lime Pit

A fault in fired bricks, a lime inclusion in the clay will expand more than the clay as the brick is fired, it usually spalls off small round areas on the brick. Lime

• Firing Cracks

Firing cracks are due to the clay in the brick not being dried sufficiently prior to firing.
There is one in the brick above, just to the right of the Lime Pit.

Historic Bricks.

A wealth of information and photos of Australian historic bricks is available here.
http://australianbricks.webs.com/apps/photos/