Does any body know how to make thermocouples from MIMS wires?

[peuray]

As the title states, does any guys know how to make such thermocouples from mineral insulated metal sheathed wire?
We have a vey special case usage, and may need lots of thermocouples. So we are planning to make these thermocouples onsite!
Is there any special steps we should follow? such as welding the hot junction, moisure preventation, and cold junction connecttion with extension wire?

your sugestion will be highly appreciated

 

[EdStainless]

1. Make sure that you have TC grade material. Store it sealed.
2. You will need to develop the tools and procedures to cut, strip, and clean the ends.
3. Arc welding the junction is the most reliable way to go. There are commercially available units to do this.
4. You need to be able to test each TC at some fixed reference temp to validate them. If you care about getting closer than +/-25F.

These will be exposed junction TCs and the MI will be exposed as well. You will absorb moisture and what ever process chemicals are around.
If you need them sealed then you will have to find a sealant that works at your temperature and environment. This could be anything from a silicone to a high temp grout.

Do you have to use MI? Insulated wire is much easier to work with. And given the finite life of exposed junctions it might last almost as long.

Have a written procedure, practice lots, and have a method to qualify each operator and each TC. A bad TC could cause you a lot of grief if you rely on it too much.

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P.E. Metallurgy, Plymouth Tube