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Topic: Where to get stainless steel NTC thermistor probe? (Read 4 times) previous topic - next topic

Chagrin


At those temperatures I would suggest a thermocouple rather than a thermister.


I'd agree. It's also pretty easy to find stainless/threaded probes on eBay (example1, example2) or elsewhere.

JeeLabs and Adafruit both sell the thermocouple amps you'd need to interface with the Arduino.

Constantin

I agree with the recommendation re: adafruit thermocouples and MAX6675 thermocouple boards. Great stuff at reasonable prices and more importantly, well documented libraries that make getting good results relatively easy. I use a K-style thermocouple in my reflow oven project (rocket scream shield).

howellboyd

Sorry to revive an old topic but I was wondering what you did afterwards?  Are those stainless steel k-type thermocouples food safe?

I'm going to take a stab at making a coffee roaster myself.  Were you happy with the quality of yours?  Is there a significant improvement in the taste over buying roasted beans?

Thanks!

Constantin

I have been very happy with my thermocouple (TC), though it is not sheathed inside a probe - the weld is exposed. For your application, a sheathed TC might make more sense (i.e. a stainless steel tube with TC inside) because it's easily cleanable. Besides a higher cost, the other downside of a sheathed TC is the longer time constant re: temperature. However, for your application, you should be fine.

Omega sells lots of stainless-clad TC's and I'd be surprised if E-bay doesn't feature them also. I have no need for food grade safety, as my TC is being used strictly to make printed circuit board assemblies (i.e. mounting surface-mount chips on them). That TC is affixed inside the oven on a PCB so it's time constant is also longer, but hopefully analogous to the time constant of the solder pads on a PCB inside the oven. So far, I have had great success.

ajakef

I recently made a yogurt maker with similar requirements--food-grade thermistor probe for temperatures up to boiling point.  This probe worked very well for it; I'd recommend it for similar projects.

http://maverickhousewares.com/et73.htm

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