Clay used with the Lutum extruders
The power of material use is a combination of physical appearance, its mechanical properties and the solution used for.
Clay mixing
The best clay to start with is Stoneware clay which needs to be mixed with water depending on nozzle size, print shape and cartridge size you have a wide variety of mixes you can use. Its best to follow the clay mixing manual you can download in our shop and build upon it yourself.
Some clay types, like porcelain or grogged (chamotte) clay need special treatment or a different Auger in the extruder; porcelain need additives to get the right viscosity for printing. because there are many varieties of porcelain we can’t advise on the right additives, you will need to research this yourself and create your own unique clay mix you can print with.
Other clay types and colors
You can choose different clay types like terracotta or black earthenware for printing. Most of these types only need some additional water to become printable. You can also add pigments to Stoneware to get exotic results.
Stoneware clay
Stoneware is a type of pottery which is impermeable and partly vitrified but opaque. It is made from stoneware clay fired to high temperatures. It does not require glazing. Its water absorption is less than 1 percent and is greyish in color.
Stoneware is made out of a natural occurring clay tape. It consist out of different amounts of Kaolinate, mica and quarts. Impurities are present and the reason for the grey look of fired material. The base material is also known as ball clay.
“The name ‘ball clay’ is believed to derive from the time when the clay was mined by hand. It was cut into 15 to 17-kilogram cubes and during transport the corners of the cubes became rounded off leaving ‘balls’. The ceramic use of ball clays in Britain dates back to at least the Roman era. More recent trade began when a clay was needed to construct tobacco pipes.
Traditional stoneware can be fired twice if the end produce needs to be glazed. First burn is around 900 °C and called biscuit firing. The second one, to form the layer of glaze on the product, called the the glost firing, is around 1250 °C.
First examples
The earliest examples of stoneware have been dated to at least 1900 BC at the Indus Valley Civilization. An industry of a nearly industrial-scale mass-production of stoneware bangles flourished there throughout the civilization’s Mature Period between 2600 to 1900 BC.
Another early form of stoneware has been found in eastern China Zhejiang region at Deqing. From the various definitions of high-fired ceramics, it is agreed that these early brownish olive glazed stoneware products were from the late Shang dynasty (1750 BC – 1122 BC). Large quantities were eventually produced by the Han dynasty (202 BC – 220 AD).
Source: wiki Ball_clay & wiki Stoneware
Author: Yao vd Heerik, VormVrij® 3D
http://lutum.vormvrij.nl/?page_id=735