Heat Treatment Furnace Thermocouple

I am currently building a 3Kw electric heat treat oven. The only item I am concerned about is the K type thermocouple for the
Watlow controller. This is encased in a 5mm diameter rod which will enter the chamber from the rear to expose about 25mm. My feeling is that I should cover the tip with a steel cap of similar thickness to the item that I am heat treating, that way the sensed temperature will be relative to that seen by the part. Any comments? and how is the thermocouple handled in a professional oven? My controller does have a "ramp at n deg/min" capability.
Richard
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"Richard Edwards" wrote in message

My pottery kiln thermocouple is protected by a ceramic thing looking like a small test tube. The one in my heat treatment oven is apparently buried in the wall. When the furnace is up to temperature the thermocouple will be in thermal equilibrium with it's surroundings and given enough time so will the object being heated.
Andrew
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On 27/05/14 14:45, Andrew Mawson wrote:

Down at the workshop we have a L&L top loading ceramic kiln and it has double ceramic sheathed thermocouples and it does have a standard offset programmed in to correct the temperature reading at high temperatures, IIRC it's about 25C, so it reads high at ambient temperature but should be OK at the top end and it goes to 1260C.
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On 27/05/2014 14:45, Andrew Mawson wrote:

The pottery kiln seems to adopt my suggestion. My heat treat oven is built from Type 23 Insulating refractory bricks. If I bury the TC in an insulator it could be way out.
Richard
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