Homebrew PCBs

Stefan Trethan <stefan_trethan@...> writes:
> If you do that you may as well stick to a sheet of foam rubber
> pressing the stack up against the glass and dump the vacuum.

I suppose, if I could figure out how to hold the glass down.  Not much
extra room around the edges for screws, the box is sized to fit the
glass with little margin.

> I sort of thought the whole purpose was to get a double-sided
> exposure machine.

No, it's a single sided exposure box.  I'm just trying to hold the
film against the board.  Old way: the pcb sits on the plywood bottom
of the box, the film sits on that, the glass sits on that.  Expose
from the top.  New way: similar, but pcb sits on stack of paper, glass
has gasket, vacuum sucks out air between pcb, film, and glass, holding
the film against the photomask.

For DS boards I etch the two sides separately so I can align the films
more accurately.