Homebrew PCBs

Mine is a chunk of plywood with some gasket material in a square around
the edge.  Plate glass rests on the gasket, and a hole in the plywood
connects to the vacuum.  The trick is to use the minimum amount of
vacuum needed - too much of course breaks the glass.

Also, I use some cut up card stock to raise the pcb if it's thin, so
less vacuum is need.  About 3-5 inches should do.  You can even get this
much vacuum with a shop vac and a home made venturi, it's not much.