How to use crucibles:

SAFETY

Proper safety clothing, aprons, boots, shoes, gloves and eye protection must be worn at all times when melting metals. Ensure that no moisture is introduced into the melt. Water may cause spatter. Provision should be made beneath your furnace to catch any molten metal that may spill or leak out if the crucible cracks.

CLEANING

Crucibles and melting dishes should be carefully cleaned out between melts, or at least once per day. Do this while the crucible is hot to remove build-up of oxide dross. In tilting furnaces clean your crucibles in a horizontal position.

STANDS

For best results the crucible stand should be made of the same material as the crucible. This ensures even, uniform heating of the crucible base and provides good support. The diameter of the crucible stand should be the same diameter as the bottom of the crucible, or larger. The bottom of the crucible should be level with the centerline of the burner in fuel-fired furnaces. The stand and crucible should be positioned in the center of your furnace.

CRACKING

There are many reasons a crucible may crack. Thermal shock is very common problem. Just as hot water poured on an ice-covered windshield will crack the glass, setting a hot crucible on a cooler surface may crack the crucible.

Leave at least a 5/16 (8mm) gap between the upper wall of the crucible and the furnace lining to allow for expansion. Failure to leave a sufficient gap can lead to cracking your crucible.

Be sure the furnace drain hole is sealed to prevent cooler air from contacting the hot crucible and causing premature crucible failure.

CRUCIBLE CARE

Store your crucibles in a warm, dry location
Do not stack your crucibles
Do not roll your crucibles
Check for cracks or hairline fractures before use
Be sure the crucible stand is flat & larger than the crucible bottom
Heat the crucible evenly
Do not drop material into a hot crucible
Use tongs to slowly lower and place material into a hot crucible
First charge with returns, then add ingots
Add flux after metal is molten
Use tongs to lift a hot crucible
Fit tongs evenly from both sides
Lift from the lower third of the crucible
Empty your crucible while it is still hot
Do not let metal cool and harden in your crucible
Cleaning hot crucibles removes excess oxide dross


CAUTION: Melting metal is extremely dangerous. Always perform in a well-ventilated and well-lit room. Follow all safety precautions. Do not melt metal if you are under the influence of any drug or alcohol, or have not had enough sleep. Follow these crucible hints and instructions at your own risk.

© Q.T.E. North America, Inc.