Bear in mind this is NIR (Near Infrared- eg. TV remotes) not FIR (Far Infrared- eg. heat). I don't have a FLIR camera that can see far-infrared, but I have a modified DSLR that can see near-infrared. Both NIR/FIR are invisible to the human eye.
The sparks and hot metal are MUCH brighter in-camera than they were in person or to a regular camera
It would be interesting to see what this looks like in a UV-converted camera.
![](https://s2.save4k.ru/pic/KP8E1N7GeQk/mqdefault.jpg)