If you wish to create filigree jewelry using porcelain, up to now you had been forced to make a mass based on complicated mixing ratios and the had to roll it out finely. Jewelry artists could not know whether the work was successful until after it had been fired. But the porcelain foil Keraflex offers goldsmiths the option of achieving calculable results with less effort.
The starting basis for Keraflex is porcelain mass. It is mixed with special bonding agents and softeners and formed into a flat foil in a patented method. It is as thick as quite a stiff sheet of paper and feels like foil. Keraflex is supplied on a transparent carrier foil made of plastic. This makes it easier to handle and one side of the high-quality material remains well protected. Keraflex can be bent in any direction and is flexible, can therefore be adjusted into any form, just like paper or cardboard. The porcelain foil becomes even softer when it is slightly moist. This leads to absolutely limitless opportunities in porcelain processing. Another advantage of Keraflex is that the ceramic mass does not need to dry before firing.
The foil can be cut to measure in any form using a knife or scissors. Additionally, the foil permits the printing, decoration, stamping, painting or punching of patterns. It is recommendable to make the foil more flexible by submerging it in a water bath for approx. 30 seconds or by moistening it with a sponge. When it is moist, it behaves like a waxed cloth or like cloth. This state is absolutely perfect for stamping or printing, for example. Beautiful effects can also be achieved by striking material patterns in the wet foil.
The right firing
Firing shrinkage also occurs with the porcelain foil Keraflex; this means that the object surface is reduced due to the heat. In order to achieve good transparency, a sensible firing temperature is between 1,260 and 1,280°C. Transparency of the pieces increases, the higher the firing temperature. On the other hand, the higher the temperature, the more melting flux. This may lead to deformation. The form of the pieces is also significant. But if the firing temperature is in a range of 1,250 – 1,260°C, users can feel safe.
The heating-up rate should be set at 120 – 180°C/h. The items are generally left to cool on their own, but if possible, the heating-up temperatures must also be adhered to in this process stage. In the event that the piece is intended for glazing, it requires a sufficiently solid and porous surface. When exposed to the pre-firing temperatures for ceramics of between 800 and 1,070°C, the foil is as delicate as an eggshell. This is why experienced users recommend preliminary firing al 1,220 °C to 1,280°C, therefore close to the maturing temperature. The ceramic foil becomes increasingly transparent, the hotter the firing temperature. On the other hand, however, the propensity towards deformation is increased as the firing temperature rises.
A good transparency with sufficient form stability is achieved at a firing temperature of approx. 1,270 – 1,280°C, depending on the form and size of the jewelry object. Every goldsmith should conduct their own tests to ascertain which temperature in his or her furnace achieves the best results. Flat items are most likely to remain even if they are fired between two firing tools made of aluminum oxide. The porous plates allow the gasses to escape through the ceramic foil during firing and contribute with their weight to the object remaining absolutely even. The foil can be glazed as early as before the first firing and then the colors are baked.
What do you need barbotine for?
Barbotine can be used very simply in order to bond together individual pieces of porcelain foil. The barbotine consists of porcelain mass, a binder and glue. The best way to apply it to the bonding points is with a brush. It dries very quickly, so rapid work is required. Even if the connection appears very unstable after bonding, it is extremely solid after firing. Moist plates can also be bonded using barbotine. Jewelry artists can create a very beautiful interplay of light and shadow if they stick smaller pieces of the same foil on to a 0.5 mm base foil. After firing, the thicker sections are less translucent than the base foil, thus creating pretty light effects.
After the foil has been moistened, items of jewelry are frequently folded or rolled. It is quite often sensible in this context to stick the ends together with some barbotine. It is also possible to fix the piece with clamps or other tools until it is dry.
How can you decorate Keraflex?
There are extremely diverse possibilities to decorate Keraflex. For example, the unfired porcelain foil can be painted with barbotine or fired parts can be colored with luster or with metal salt solution. It is also possible to paint the fired foils with underglaze paints, transparent glazing and then repeated firing at a low temperature (mostly 1,050° C). The raw foils can be stamped or decorated with hole patterns or wattling. The possibilities are almost boundless.