Andrew Zonenberg on Nostr: After a first pass of sanding, there's some edge rounding (hard to avoid, although it ...

After a first pass of sanding, there's some edge rounding (hard to avoid, although it got less pronounced later on when I switched to a fresh sheet of sandpaper) and we see clean copper around the edges while the middle is just scuffed soldermask that's almost impossible to see anything through.

But the good news is all of the layout of the bottom copper layer (let's call this substrate metal 4) can be seen through the soldermask in the first image, so nothing too valuable was lost