The Iittala Kivi votive candle holders are made of pressed colour-glass. This means that the glass is dyed thorough. The melted glass that is used to manufacture Kivi is initially transparent.
To give the colour to the Kivi tea light holders, “metal dioxides” are added to the initial mass. These are “inorganic oxides” that don’t only avoid a fade of colours because of the sunshine over the years, but also ensure being dishwasher safe and scratch resistant.
Kivi is available in three different price categories. The price difference at the articles that are made of pressed colour-glass comes from the different manufacturing processes, and the colours that are used at every method.
1) Manufacturing process
a) Automatic press manufacturing
The Kivi tea light holders in this price category are produced with an automatic press in the Iittala factory. The machine leads the glass mass automatically into the press form. This occurs really fast and no manual work is needed for it. At the colour-less clear Kivis, the production capacity makes up a few ten thousand pieces every week. With the automatic press, “cold” kivi-colours (such as e.g. bright-blue, moss-green and grey) can be produced when colour is added to the ground-mass. Via the supply conduits, colour-granulate is spread on the clear mass and both items are then mixed to a homogeny coloured glass. Every time a colour is changed to manufacture a different Kivi colour the supply conduits are cleaned by extracting the colour that was used before. Afterwards a new colour can be introduced into the system. At the Kivi-group production a great oven helps (this one melts clear glass masses continually), to put this manufacturing quantity into practice.
The ground mass that is used for the A group, does only suit as an initial material for “cold” colours. If pink particles are added to this initial mass, it would lose its colour. This is why a different “recipe” for the ground mass is intended by the B group.
b) Half-automatic press manufacturing
The Kivi tea light holders in this price category are manufactured with a helping robot hand in the Iittala factory. The coloured glass mass is initially melted inside a small furnace and then became a formed candle holder made by robotic hands. In a small furnace “warm” Kivi-colours are produced because every colour has its own recipe for the ground material. At this production system, the smaller press starts to work; this one is not as efficient as the automatic press (production system for clear and cold colours). The robot works that makes up smaller colour parties and less efficient machines, as well as more production time – reduced the production capacity and makes the Kivi manufacturing more expensive.
c) Hand pressed
The Kivi votive candle holders in this price category are manufactured (hand pressed) by three workers in the factory of Nuutajärvi. Every glass mass has to be melted separately in the furnace that is also used at the manufacture with the half automatic press. The glass mass is taken out of the oven by a factory worker with a pipe to be then introduced in the hand press. This manufacturing process is costly and needs manual work. This makes the whole manufacturing process longer. The production capacity makes up only some thousand pieces every week. Moreover a red Kivi tea light holder has to be heated once again to get a chemical reaction that enables the intense ruby-red colour (if not it remains yellow).
Besides the versatile manufacturing processes, also the colour plays a role in the Kivi tea light holders-price. Some colours (metal oxides), that have to be added to the colour-less glass mass are more expensive materials. This includes the oxides overall, these are used to create the “warm” colours (cadmium-selenium for red, manganese for purple, cerium, titanium and selenium for yellow). The materials that we use for “clear” colours are cheaper (steel, copper, cobalt, nickel, chrome for blue and grey).