Safety and Best Practice SiC TubesThermal Shock Characteristics: The high Graphite and Silicon Carbide content (circa 90 %) give the thermocouple protection tubes very high thermal shock resistance which allows repeated immersion into molten aluminium without risk of cracking. Additional coating of the tubes is NOT necessary. Safety and Best Practise:TPTs from any source should never be immersed in molten aluminium or other metals unless they have been previously dried at above 100º C to remove any water that may have been accidentally spilled on them. This is also applicable to any other fluids such as oil, suspending liquids for wash coatings etc. In the latter case the tubes must be heated to a temperature sufficient to remove them. Failure to carry out the safe practices detailed above risk causing cracking of tubes in an explosive manner. It is considered best practice to keep the thermocouples in a warm and dry storage area.