The bar is clamped in a metal vise, so the vise is very slightly heated and that side of the bar is much cooler.
Taken using the Topdon Android attachment.
this post was submitted on 01 Sep 2026
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Metal is pretty reflective in IR range, so you're mostly measuring the room temp. You could fiddle with the emissivity settings, but the best way I've learned to measure reflective objects is small pieces of kapton tape. Highly emissive and doesn't greatly change the thermals, so you can trust the measurement much more. That 100F temp might be closer to 300F for all we know.
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Nice tip! When I buy a thermal cam, I'll put in an order kapton tape too.
I do have some kapton tape. I've heard black sharpie on masking tape too. The cutoff piece was definitely uncomfortable to hold but not in the range of instant burns; also a pretty dull surface. I wouldn't be surprised if it were a bit about 107⁰F but I don't think it was near 300⁰F.
Haven't used sharpie and masking tape before, but I've used kapton at relatively high temps (500F). Contact pain for metal typically starts around 113F (45C), but I was referring to right where you were cutting, not where you were holding.