Polaris Easy Cast Instruction Manual page 28

Fig. 4: The correct method of placing alloy ingots inside the crucible
Before using the crucible, make sure of the internal cleanless and
then heat it slightly (pre-heating through the cylinder furnace) to
remove any moisture. Pre-heating would prevent cracking of the
crucible walls in cold temperatures and increases its useful life.
Fig. 5: Pre-heating the crucible in cold ambient temperatures
Take Care not to damage the crucible in any way when positioning
it inside the machine.
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