The making of bells begins with the making of a stone core, shaped into form with the help of a profile pattern, the sjabloon. On the surface, a layer of mortar made of sand and cement is applied, producing the so-called "false bell". A layer of wax, on which the letters and other symbols of commemoration will be inscribed, is then applied to the surface of the "false bell". Then several layers of very fine clay will be applied, to form the mantle.
The profile of the mantle is checked against a steel profile pattern, the outside sjabloon. Areas that don't fit the pattern will be filled with mortar. Fire is used to set the clay, melting the wax layer. Molten metal (of 20% tin and 80% copper) is poured into the mold, and left to cool. The core is removed, and the bell polished. With the help of modern electronic apparatus, the bell is tuned.
After polishing, the bell is then tuned. Principally the bell will be tuned to five partials. For example, with a C2 bell the tones C1 (hum-tone), C2 Prime, C3 Nominal, Es2 (tierce) and G2 (quint) are tuned individually. The tuning is done by carefully removing the right amount of bronze for each tone from the inside of the bell. This needs to be done at different levels inside the bell to assure that all tones of the bell are very accurate. It is extremely necessary for this precise tuning otherwise ringing the bells together will not be in harmony.