DIY PCB plated thru holes?

[Terry Michaels]

Message text written by Paul Perry
>But if you are doing it photographically, will the 
sensitised surface survive the drilling?
(though, I suppose here you only need one at each corner)

paul perry melbourne australia
<

Hi Paul:

In my experience, drilling a pre-sensitized board will cause some of the
photo coating to chip off.  Instead of pre drilling the board, what I do is
print my top and bottom layer plots with registration marks a half inch or
so outside the perimeter of the board, one at each corner.  I cut the board
to the proper size and sandwich it between the top and bottom plots, the
whole thing is then clamped between two glass plates held together with
clips.  You can see the registration marks through the whole assembly, so
it is easy to confirm alignment.  Then, UV expose one side, flip it over,
UV expose the second side, develop, etch, etc.

Terry Michaels