Homemade Thermocouple

Hello Mike
Corrosive woodgas, I suspect carbonic acid, this is why a consider the gasifier and parts consumables.
After so long they will just desolve in their own juices.

Hi Dave, Enjoy them while they last. I stopped using thin metal like oil drums and went to the thicker water tanks. So far so good. There is some kind of vinegar that really wreaks havoc. Make sure you dry things out from time to time. The worst thing I ever did was flush out my hay filter with a hose. It never ever dried out and I had to finally pull the muck out and put fresh DRY hay back in. I even had a drain plug in it. Back to the salt mines … Mike

Those numbers using a heatsink are definately more exciting. I wonder if a tubular heat sink work work just as well, while protecting the copper tube.

John, why do you say the numbers are exciting or not exciting? Numbers are numbers no matter how you look at them. On the glow plugs you could pretend the decimal is not there and then it would be 19 to 25. Is that more exciting? :slight_smile:
Don Mannes

I don’t know. When I watch the numbers from the glow plug, they seem to just sit there around 1.something or 2.something. It just seems boring. I realize that it’s telling me a story about the temp in the ash pit, but it’s kind of boring. Comparred to the tc numbers coming from the same place.
Have you plugged one in yet?
I just thought of something. Maybe I should try slipping a heat sink/tube over the glowplug and see if those numbers liven-up a bit.


I ran my Imbert yesterday with one of the TC’s just above the grate. With good gas, the TC gave me 8.2 - 12.9 mv, over a one hour time. Placement of the TC is critical, below the grate temps are low, temps are highest just above the grate.

Those numbers look pretty useful. When Fahrenheit first devised his scale, he set the temp of frozen sea water to be 0, and the temp of the human body to be 10. He later changed it up so the temp of live human bodies was 100. He must have gotten bored with all those little numbers.
I put a stainless tube on my glowplug today but I haven’t fired up yet.
How much does the nickle rod cost and where do you get it?


Dave, what did you do to create the actual junction between the nickel rod and the copper ? Did you use a flaring tool or the such to compress the copper around the nickel rod ?? I see the pliers in the picture. I can not do videos here so don’t have a clue what was in your video. Thanks, Mike

The nickle rod is for welding cast iron and costs $ 40.00 per pound and up but can be bought a couple of rods at a time. Welding supply stores, farm stores or most of the big box building centers.
I brazed the junction with brass

Dave, I have done that with the roll wire I used to have. I always had a little silver solder on hand and I recall it working just fine. I use bronze now. Mike

We went cruising for about an hour this evening. And I found an interesting coincidence. DonM should like it. Most if the time the reading from my ash pit thermocouple was 13mV. And the reading from the glow plug(in the ash pit) with a stainless shield was 1.3mV! The coincidence held true from 11 (1.1) to 18 (1.8). I guess they were perfectly good numbers after all.
Dave, I have to get some nickel rod and try out your fine instrument.

John S, I do like it!