I'm doing some testing on some HFBR2412 little opto-receiver plastic cube things. I figured I'd epoxy it dead-bug to a square of copperclad FR4, and then wire parts up to it. The thing is, epoxy doesn't stick to copper very well, and sooner or later it will pop off.
So I figure I'd cut away a square of copper so I can epoxy directly to the fiberglass.
So here's the Discovery:
Buff the board with a Scotchbrite pad.
With an x-acto, push hard and cut the outline of the desired square. This is hell on blades.
Then, x-acto again, randomly criss-cross score the copper inside the square.
Get a good, hot, preferable Metcal soldering iron, tin the inside of the square, then rub it pretty hard with the iron. All the little scored diamonds will rub right off. Do this all the way to the outline.
To really make the edge of the cutout look pretty, buff with Scotchbrite again.
waiting for the epoxy to set; why I'm doing this is another story