James’ chemistry setup on the roof! The left container has de-ionized water, and the right one had Cu plates suspended (electrochemistry 101!)
Looking at the copper plated vias under a microscope. The point is to fill in Cu along the cylindrical drill holes’ surface, so both sides of the board can be in contact. The conducting ink helps get the Cu deposits targeted.
This is what the whole board looks like. Pink, with interesting deposits / patterns:
No plating on the edge of the Cu sheet, because it wasn’t completely immersed in the bath!