Inside Kaldewei: The birth of a bathtub
enamel – this special combination of glass and steel is a time-honoured
tradition to which Kaldewei has been devoted with a passion which now extends
across four generations.
its 100-year corporate history, the bathroom manufacturer has consistently
pushed the boundaries to improve this material and its manufacturing processes.
Today, steel enamel is a high-tech material, whicht is used worldwide. Especially
for the bathroom, unique objects can be created from robust steel and superior
From natural resources to enamel
borax, Scandinavian feldspar, quartz and soda – these and other natural
substances have been the ingredients used for millennia to produce enamel.
Kaldewei has steadily advanced, refined and optimised the unique formula and today
is the only bathroom manufacturer worldwide to produce its enamel in its own
melting furnaces – based on a top-secret proprietary formula.
raw materials are mixed in rotary furnaces heated to around 1,300°C. The
resulting red-hot enamel mass is then quenched in cold water causing it to
solidify before it is broken down into tiny glass granules, known as enamel
frit. In rotating ball mills, the enamel frit is mixed with water, additives and
pigments to create a sprayable enamel slurry.
The titanium steel bathtub blank
Kaldewei bathtub blanks are made from steel of the finest quality, which must be
sufficiently ductile for deep drawing and moulding, while being suitable for
enamelling. In the first step, the micro-alloyed titanium steel blank is deep-drawn
into its ultimate shape on a bathtub press line that applies forces of up to 1,200
tons. Next, the waste and overflow holes are cut in a partly automated process,
and the earthing and transport straps and bath lugs for the feet are welded on.
Custom holes for handles, fittings or whirlpool jets are added by way of laser
Steel enamel: bonded for eternity
and enamel now need to be permanently bonded. In this process, the base coat is
sprayed onto the blanks by robots and fired into the surface at around 850°C. Steel
and enamel form a molecular bond that cannot be mechanically separated and protects
the whole tub body. The final coat provides the enamelled product with its
visual and haptic properties and the needful durability. Steel and enamel have
now formed the inseparable bond that makes the bathtub, shower surface or
Long life and rebirth
bathtub undergoes rigorous quality control testing before leaving the Kaldewei
factory and is released for sale only after it has successfully passed the
inspection. This applies to every bathtub, shower surface and washbasin – without
exception. The unique material quality is backed by the company with a 30-year
guarantee on its products and because all bathroom solutions are produced from
pure, natural resources, they can be fully recycled at the end of their lives –
ready, perhaps, to resurface as a brand-new bathtub.