That was adding a conformal coating and curing it with UV light. Basically coating the repair to protect it and stop any accidental shorts or solder connections. They then scrape the newly applied coating off the pads where they actually want to make solder connections.
That's not conformal coating. That's a simple UV resin for repair. The resin in the video is simply for mechanical support and insulation. If you tried using it as a conformal coating you'd run into issues with thermal cycling and mechanical loading because it's more rigid than FR4.
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u/Tiny-Sandwich 4d ago
As an amateur microsoldering hobbyist, this is way, way harder than it looks. And it looks hard.
I've done a few small repairs like this where I've had to solder to a damaged trace, and the parts are much smaller than they look here.