Rohde Fusing Serie Notice D'utilisation page 105

10. Fusing firing
10.1. Fusing kiln
10.1.1. General information
NOTE
The fusing kiln is unsuitable for firing ceramics!
1-sided heating and the corresponding heat distribution are unsuitable for firing ceramic
products.
10.1.2. General description
In the fusing kiln, the heating elements (infrared heaters in quartz glass tubes) are only installed in the lid. They heat
the top of the glass material over a large area from above so that the heat from the heating elements radiates over
the entire surface of the glass. This reduces excessive temperature differences in the material and prevents cracks.
10.2. Notes on fusing firing
•
Test the kiln:
Successful fusing firing essentially depends on knowing how the heat is distributed within the kiln and the
glass.
•
Test the glass:
The successful fusing firing not only depends on the known coefficient of thermal expansion (CTE) of the
glass. If glass from different manufacturers or from unknown origin are to be fused together, the
compatibility of the different glasses is not guaranteed. In this case, the behaviour of the glass to be used
must be tested in the kiln.
•
Average heating rates:
− Glass with a thickness of
− Glass with a thickness of
− Glass with a thickness of
•
Only glass with the same coefficient of thermal expansion (CTE) should be fused:
− The thermal expansion coefficient describes the expansion of the glass during heating at temperatures
between 20 °C and 300 °C.
− When glass with different thermal expansion coefficients is fused, the end product can crack or break
during cooling in the kiln or after removal from the kiln.
− Specialist shops have special glass material for the fusing kiln.
•
In fusing firing, certain factors in the glass can cause uneven heating and cooling.
These factors include
Hence the tip:
It is best to heat up the kiln slowly to achieve a more even temperature distribution in the glass.
1–20 mm
20–100 mm
100 mm & more
− the glass thickness,
− the material properties of the colours used, as well as
− the poor thermal conductivity of glass.
103 / 298 - EN -
= 17 min. per 1 mm glass thickness
= 27 min. per 1 mm glass thickness
= 33 min. per 1 mm glass thickness