Cooling Steps - Katanax K2 Prime Manual

Cooling steps

The cooling process is normally divided into two distinct steps. The first cooling
stage (Cooling 1) is a natural-convention cooling, that is, without any forced-air
cooling. This allows for the melt to completely fill the molds while the molds are as
hot as possible, and is of key importance in the stabilizing of the melt.
Indeed, in most cases, if we were to start the forced air circulation immediately
after pouring, the bead would not cool down uniformly, and residual thermal
stresses would remain in the solid disk. This can cause hazardous bursting of the
produced disk, in the next minutes, hours or even days.
On the other hand, and again there are exceptions, if the blowers were to start
too late (Cooling 2), a crystallization reaction could occur if the molecules have
enough time to arrange in an orderly fashion. Crystallization reaction cause the
transparent melt to become milky-opaque, typically from the edges towards the
center of the mold, pushing the still-liquid melt to the center and upwards as
crystallization progresses, thus creating a volcano-like structure.Therefore the
solution resides in finding the correct time for still-air cooling (Cooling 1), and then
the blower can start and work until the molds are comfortably cool to the touch.
Hence, the duration parameter is very important, especially for "Cooling 1".
Duration
one to two minutes is a very good starting point. Thereafter, "Cooling 2" can be
set for as many minutes as needed, and this parameter will be roughly
proportional with the melt and mold combined weight.
Crucible position after pouring
be the same as the pouring (typically 120°), and the tilting angle of "Cooling 2"
will be ninety degrees (90°) to prevent residual drops from sliding on the outside
wall of the crucible, or fall onto the cooling bead. This will give some time for the
flux to pour completely out of the mold during "Cooling 1", while partially
straightening the crucibles when the blower starts at the beginning of "Cooling 2".
Note that, if pouring was turned off, then the fluxer is in "non-pouring" mode, and
so will allow for a rocking at this step, just like a normal heating step. This is
useful to spread the melt onto the crucible walls when making peroxide or
pyrosulfate fusions.
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Step duration (mm : ss) is adjusted by
pressing on the plus and minus buttons.
Generally speaking, a "Cooling 1" duration of
In a typical cooling step, the two crucible-
related parameters are not used to control
the crucible rocking motion, but rather to
control the straightening up of the crucible
holder, after the pouring.
Typically, the tilting angle of "Cooling 1" will