Our friends from Duravit share some insight and behind the scenes info required to understand the raw materials, production and development of ceramic sanitaryware.
Ceramic sanitaryware consists of what is known as the “body,” which is covered with a glaze and baked in a kiln at high temperatures of around 1280 °C. This results in a high level of hardness, which creates durability, even in public sanitary facilities. The hygienically smooth glaze makes the finish wear- and scratch-proof, and easy to clean.
The basic ceramic mass is manufactured using natural raw materials clay, kaolin, quartz and feldspar. These raw materials are processed with water in large containers to create what is known as “slip” and then poured through casting pumps into the various Plaster of Paris moulds. After about an hour, the 8- to 12-mm thick blank can be removed from the mould to dry; later on, it receives finishing touches during a process also known as “white-machining.” Once the body has been freed of dust, the glazing process is performed.
Quartz, chalk and feldspar are mixed together to create the glaze, and, using a hand-operated spray gun or automatic spray equipment, the mixture is applied in a thickness of 0.8-1 mm to the still ‘green’ sanitaryware item. Following a further brief drying period, the unfired, glazed pieces of sanitaryware are fired in gas-fired shuttle or tunnel kilns. The ceramic parts shrink by up to 11 percent during this drying and firing process. Sophisticated firing aids and decades of experience help keep the various models from contorting during the firing process, and rather, ensure they shrink and assume the perfect shape.
Everything is checked, down to the finest detail, during a meticulous final inspection. Only then can the item leave Duravit and make its way into the retail sector. Depending on the composition of the material mass, a distinction is made between sanitary porcelain, (vitreous China) and fine fire clay and stoneware. Vitreous china is used most commonly in the area of ceramic sanitaryware, because the strength and (water-) tightness of the body are significantly higher than it is with the two other types of materials, thanks to its high glass phase ratio.
That is why this material is invariably used for the manufacture of toilets. Development of the material known as ‘DuraCeram’ led to a considerable increase on the impact resistance and dimensional stability of fine fire clay, with Duravit’s product line standing out amongst the rest. With the Cape Cod bathroom range by Philippe Starck, the Luv bathroom range by Cecilie Manz, and DuraSquare – all made of DuraCeram and featuring narrow radii and thin edges – it was possible to set out on new paths in the field of design.
Glazes, colours and surface finishes: A glaze is a glassy coating that gives the body its smooth and shiny finish and makes ceramic sanitaryware resistant to household cleansers (acidic or alkaline). Pure, natural silicon quartz crystals are the primary constituent of glazes. With only a few exceptions, glazes are usually white. Danish designer Cecilie Manz has developed a new colour generation of matt lacquers and glazes in soft shades, exclusively for Duravit. With her new Luv bathroom range, ceramic finishes take on a new dimension.
The outsides of the washbasins, for example, can be optionally glazed in a satin matt white, grey or sand colour. Each colour is sprayed on by hand in two steps using a template. The contrast between the glossy white glazed inner basin and the matt exterior produces individual pieces with a special look and feel. The oval above-counter basins made of DuraCeram stand out thanks to their fine contours, large inner basin and crisp edges. Functional finishes were important milestones in research. Their mission is to reduce the use of cleansers and to provide toilets with antibacterial finishes.
This is how the WonderGliss coating optionally fired into the ceramicware, has been proving itself for years in washbasins, toilets and bidets. Sanitary ceramics featuring WonderGliss stay smooth and clean for longer and are thus very easy to clean. Duravit is constantly researching and working to further improve the excellent properties of ceramics. A responsible choice of materials, innovative technologies, detailed craftsmanship and emphasis on quality create unique, durable products highlighted by Duravit’s unique and one-of-a-kind design.