High temp thermometer?

I

Iron&Light

Member
Hi Everyone,

I still do most of my heat processes at the forge. I've got a two burner gas setup that oxidizes the heck out of metal. I generally shield the blade within a pipe to help with decarb if there is any soaking involved.

I am looking for a reliable high temp thermometer. I have gone through two cheap Chinese ones in very short order. I ordered models with ceramic shields to keep the probe in better shape, but those broke too.

Its got to reach into the hot forge and into the pipe and not break or melt. Up to 2k F would be ideal.

Can anyone suggest a good source?

I'd also love to find some of those temperature indicator crayons, but have had no luck at all. Anyone got ideas?

Thanks!
 
I can't help with the T stat but you can check on the web for poly pipe fusion equip. I use the sticks to check the faces on fusing irons for fusing pipe temps. I don't know how high they go though, I use 500 degree sticks.
 
I have a tuorial on my website for building your own pyrometer, at a significantt savings to buying a "production" model.
http://www.caffreyknives.net/forge_pyrometer.html

The reach can be had based on the thermocouple you choose to use. (the thermocouple I have listed on the website is intended as a general purpose one for a forge application).
 
Get yourself a PID reader and K-Type probe. Probe and terminal block is McMaster-Carr http://www.mcmaster.com/

K-Type 32° to 2300° F 1/2" dia. wire 8 ga. 3859K34 $15.96

Terminal Block for Thermocouple Assembly 38705K82 $11.43

PID Reader is Auberins https://www.auberins.com

1 x Universal 1/32 DIN PID Temperature Controller (SYL-1512A) $37.56

If you need to protect it from breaking, just be careful with it. I mostly burn the probe from running it too hot......like way past the 2300 degree mark. They will hold up and run just fine up to 2350-2400 degrees. This setup is easy to rig up and you can put the PID in a J-box if you want. You will need to be a little creative with the Terminal Block because the 8 ga. wire and ceramic sheath don't fit through the hole. Just run the probe wires through the hole, bend the probe wires and screw them to the terminal block.

I hope this helps, it works for me!
 
Yep, Ed this on works too. What is the probe wire gauge? I like the 8 gauge wire with the ceramic protector, but the Omega one looks like it has SS
 
Hi Rome!

The one I listed on my website is an SS sheath. I used the 8 ga. wire with the ceramic "beads" at one time..... but they seemed to burn out quickly in the forge.
 
There are 2 things you need.

One is a readout. If you can cope with degC, search on ebay for a TM902C and buy at least one. It's not pretty, it's not particularly rugged, it's not American. It is accurate. It only takes a Type K input and reads to 1368 degC or so (2495 degF or so). It is under 5 bucks delivered. The cheap, useless-looking Glass-Fiber insulated bead probe it comes with is actually very good for checking tempering setups up to 400 degC (750 degF).

If you need to use a different thermocouple type, or must have degF, you'll need to shop around or do it Ed's way.

The second thing is a thermocouple. This is the part that really needs the thought.

Realistically, I'd say this is something you are best talking directly to the supplier about, because there are just too many variables to cover them all in a sensibly-sized post (or thread).

Rome's link is to a ceramic-sheathed kiln-type thermocouple. It should work for you if the rest of your setup is like Rome's.

Ed's link is to a Mineral Insulated thermocouple assembly. It should work for you if the rest of your setup is like Ed's. It is worth noting that, for the MI units, the sheath material is the thing that has the biggest effect on the temperature range and longevity at any given temperature.

Your setup is probably a bit, but only a bit, like both.

I'd strongly advise sitting down with a notepad, pen and decent cup of coffee and talking to the technical sales guys at Omega.

I type slow, so I'd use the phone, but live chat might be better for those with decent typing speed.

http://www.omega.com/

It is also worth taking a good look at your overall process and seeing what you might be able to change.

For example, if your burner setup is giving Oxidizing conditions, it may well be worth fitting chokes to the burners first. This might improve control at the same time as providing a much less aggressive atmosphere for the thermocouple.
 
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