You can use Digi-Sense 08541-06 Type-J PVC Thermocouple Wire to construct your own probes. It comes as a 100' (30.5 m) spool, which makes it ideal for fabricating longer extension cables, as well. The PVC insulation is designed for temperatures up to 221°F (105°C).
|Temperature Range||-20 to 221°F (-28 to 105°C)|
|Error Limit||±4°F (±2.2°C) from 32 to 545°F (0 to 285°C); ±0.75% reading from 545 to 1,400°F (285 to 750°C)|
|Size||0.08 x 0.13" (2.03 x 3.3 mm)|
|Product Length||100' (30.5 m)|