Magnetic Thermocouples

[fhon]

Ok, so I know people (some on this site too) have have used thermocouples to measure the the service temperature of their stoves. However I haven't been able to find magnetic mounting ones that will work. I've seen them at omega but the leads are not long enough. I'd love to be able to find a magnetic mount that I could use with one of the many thermocouples out there.

I was wondering if any has any experience with this or would even have a suggestion on another way to mount the probe.

 

[Ashful]

Do keep in mind that your stove may occasionally hit the Curie temperature of those magnets, depending on where you mount them. They won't be much use, if they fall of the stove when it gets hot.

 

[bwells794]

Check out auber instruments. I just installed hooked mine up the other day and tested it out. The magnet holds with 10lbs of force and is rated to hold that force up to 750F.

http://www.auberins.com/index.php?main_page=product_info&cPath=17&products_id=292

They even have a kit with a second wireless module so you can monitor from a different room. It works great so far. it reads out about 25F hotter than the Rutland thermometer I was using. I would have to get an IR gun to tell you which was more accurate.

EDIT: the meter itself has a buzzer contained inside of it which is substantially quieter than the external buzzer you can add. If you want to utilize the external buzzer, you're gonna want to make sure you have a soldering iron since the alarm and AC wire come as two separate pieces.

 

[fhon]

Thank you. This might be the way to go. Do, you know there is any issue with the "wire" touching the stove pipe?

 

[Fastdonzi]

If you are able to use type J or T Thermocouple I will send you a piece a length you want... (those are the only two types I have) Get a good strong magnet and you're good to go..

 

[fhon]

If you are able to use type J or T Thermocouple I will send you a piece a length you want... (those are the only two types I have) Get a good strong magnet and you're good to go..

Thank you very much. I believe I need to use type K to get readings high enough though. I'm not familiar with how to wire up the probes myself. How involved is it? Also, are you sure the magnets aren't a special "high-temp" type.

 

[Fastdonzi]

Dang it... Type K is the one I don't have a Thermocouple is simply a wire made from two dissimilar metals, the types of metal dictates the heat range it's good for. you can buy type K wire on amazon, then simply twist one end together and Viola, you have a thermocouple.. most come with high heat jackets around them. as for the magnet, you can get them as well. we bought some for work that are about 1" dia & 1/4" thick. they stick so hard that they are dangerous to handle more than one at a time.. I don't see them falling off in high heat in an Explosion...

 

[brenndatomu]

you can buy type K wire on amazon, then simply twist one end together and Viola, you have a thermocouple.. most come with high heat jackets around them

I use a jacketed type K inserted right into the stove pipe, works good as long as you burn clean. Cheap to buy with wire as long as you want. I think I gave under $10 (shipped) for mine
Edit: I just looked, $6.25 shipped. 10' wire, 212* to 1300* range (F) Working good for me...

 

[Ashful]

Dang it... Type K is the one I don't have a Thermocouple is simply a wire made from two dissimilar metals, the types of metal dictates the heat range it's good for. you can buy type K wire on amazon, then simply twist one end together and Viola, you have a thermocouple.. most come with high heat jackets around them. as for the magnet, you can get them as well. we bought some for work that are about 1" dia & 1/4" thick. they stick so hard that they are dangerous to handle more than one at a time.. I don't see them falling off in high heat in an Explosion...

We used to weld them on a car battery. Took a careful touch, but a few times and you had the hang of it. Now we just twist them and call 'em good enough.

On the magnets, it all comes down to Curie temp, and some of the stronger magnets do have lower Curie temps. Hit that temperature, and they demagnetize.

 

[fhon]

Thank you guys. This give me a lot more options.

 

[bwells794]

Thank you. This might be the way to go. Do, you know there is any issue with the "wire" touching the stove pipe?

I had this same concern. there is a semi stiff coiled sleeve (about 2-3in) at the magnet that elevates the cable to help prevent this but it shouldn't be a problem either way. the cable is fiberglass insulated and braided stainless wrapped. It stays cool to the touch on my setup. Since the cable doesn't get hot, I figured it was safe to use a staple in the trim just to the right of the fireplace to help further suspend the cable up higher to keep it off the stove... again, shouldn't matter, but anything for piece of mind and safety.

 

[WES999]

You can make your own magnetic mount TC pretty easily. Alnico magnets are good to about 1000, so you should be fine.
The drawback I have noticed is the magnet mount TC does not respond as fast as you might like, the magnet is probably acting as a heat sink.
I am experimenting with bonding the TC to the stove top with Blue Magic high temp steel repair.
http://www.autozone.com/sealants-gl...mperature-metal-repair-trilingual/515553_0_0/
So far it is working pretty well.

 

[realstihl]

The thermocouple end must be insulated or they will read too low. I've done lots of testing and the end must directly touching the surface then I used a short piece of door gasket rope with the magnet holding it down. It works.

 

[Ashful]

You can make your own magnetic mount TC pretty easily. Alnico magnets are good to about 1000, so you should be fine.
The drawback I have noticed is the magnet mount TC does not respond as fast as you might like, the magnet is probably acting as a heat sink.
I am experimenting with bonding the TC to the stove top with Blue Magic high temp steel repair.
http://www.autozone.com/sealants-gl...mperature-metal-repair-trilingual/515553_0_0/
So far it is working pretty well.

View attachment 165543

The emissivity of that painted magnet is surely lower than your stove's black paint. So, steady-state temp will not be effected by magnet... just the amount of time it takes to reach steady-state.

Even if emissivity were lower, it's heat-sinking effect would be immeasurably small, with regard to wood stove temps.

 

[fhon]

You can make your own magnetic mount TC pretty easily. Alnico magnets are good to about 1000, so you should be fine.
The drawback I have noticed is the magnet mount TC does not respond as fast as you might like, the magnet is probably acting as a heat sink.
I am experimenting with bonding the TC to the stove top with Blue Magic high temp steel repair.
http://www.autozone.com/sealants-gl...mperature-metal-repair-trilingual/515553_0_0/
So far it is working pretty well.

View attachment 165543

I can't find any magnets like this. Did the magnet and the spring loaded piece come together?

 

[WES999]

I can't find any magnets like this.

Search for 07270 magnet, amazon E bay etc. has them.

Did the magnet and the spring loaded piece come together?

No the TC, brass screw, nuts and magnet were all purchased separately and assembled.

This works better than the magnet, reads very close to the inferred thermometer with no lag.
I removed the screw lug from the TC and bonded it to the stove top with
blue magic metal repair.

 

[fhon]

Search for 07270 magnet, amazon E bay etc. has them.

This works better than the magnet, reads very close to the inferred thermometer with no lag.
I removed the screw lug from the TC and bonded it to the stove top with
blue magic metal repair.
View attachment 165892

I like this but I'm a little little nervous to try it.

 

[fhon]

I was confused how it's made but I think I get it. I was hoping I could replace the brass with copper. But it's just an upside down bolt?

 

[WES999]

It is a 10-24 brass slotted head screw with the head turned down flat.

 

[fhon]

It is a 10-24 brass slotted head screw with the head turned down flat.

Thank you