Using a pyrometer and thermocouple

[JoshEarl]

I just got a used Fluke 51 thermometer with an 8" thermocouple, and I'm wondering how I can best use this with my current forge setup. I have a two-brick forge fired with a JTH7 torch. Mainly I'm interested in heat-treating 1084 and O1 blades.

The thermocouple is 1/8" stainless, so I'm thinking it won't last long.

I played with it a bit today, and it's clear that the temps in my forge are very uneven. (I have an order in with Darren Ellis for one that will give me much more even heat.)

With this limited equipment, what's the best way that I could put this to use? I think I'm going to make another two-brick forge with the fire hole toward the back. Maybe that would make a heat chamber at the front that's more even.

Thanks for the help,
Josh

 

[A C Richards]

You are on the right track. A better forge is going to help a great deal. If you are using the thermocouple for just HT it may last for quite a while. Is it rated for the temps you would be using?? If so then great if not then get one that is. A heat chamber can help. Bring the while thing up to temp for a few minutes before you stick in your blade. This will help keeping the heat a bit more even. Let us know how things turn out..

 

[JoshEarl]

Thanks, Chuck. I was able to find some info in the archives about using a piece of pipe as a heat chamber, and I think that'll work perfectly. I'm treating small blades--straight razors, actually--so an 1 1/4" pipe should be just right. It'll also reduce the dreadful scaling I tend to get. I'm going to try to get some iron or stainless pipe tomorrow.

The thermocouple is a K type. It startled me a little to see it get red hot during the measurements, but then I remembered that all metals glow the same shade at a particular temperature. I'll just be using it for HT; I don't do much forging right now, and for that I think I could gauge the temperature well enough by eye.

Josh