Aug. Gundlach

New ceramic crucibles must be brought to working temperature before their first use, i.e. whilst still empty. MARS ISOMELT / MARS uniCstar crucibles should be heated up quickly to red heat.
Contrary to that MARS GLOBAL Graphite crucibles must be heated up slowly to dark red heat and then quickly to bright red heat.
Tongs, carrying clamps etc must be constructed in such a way, that the jaws fit evenly around the circumference of the crucible and thus avoid uneven pressure.
Do not wedge the material into the crucible! Take care that there is always a little space left between the metal and the wall of the crucible, so that the material can expand during heating. The coefficient of expansion of the metal is bigger than that of the crucible material.
Ingots and larger pieces of metal should, if possible, be preheated and carefully placed into the crucible with tongs. Pieces should never be dropped into the crucible!
The crucible must not be emptied completely every night. No metal residues must be allowed to freeze in the crucible.
Take care that the crucible is always full of metal, otherwise oxidation will take place in the upper part of the walls and this may result in cracks.
When using fluxes, be careful that these do not have direct contact with the crucible material. Pouring should be done shortly after the fluxes have been added. Never overdose fluxes!
As soon as the metal has reached pouring temperature, casting should be done very quickly. Otherwise the life of the crucible may be reduced.
When casting is finished, every slag adhering to the inner surface must be removed, whilst the crucible is still hot. This cleaning process must be done carefully, avoiding any damage to the crucible material. Use suitable cleaning tools only!