High temperature K-type Thermocouples like the model PK-1000 always had one problem: how do you
secure the fibers at the tip? For low temperatures a PE plastic shrink
tube can be used, but for probes that have to withstand 1800 degrees F
(1000 degree Celsius) that is not a solution, the plastic would just
melt and burn off. All kinds of ceramic glue or cement have been tried,
but they did not work well.
We now came up with an excellent solution: We use a thin metal wire and tightly wrap the ceramic fiber near the tip. The wire is chromel metal, the same that is used as one of the thermocouple wires. Even if the wrapped wire gets in contact with the termocouple wire, it will not influence the temperature reading.