Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>
> On Wed, 22 Feb 2012 02:27:45 -0000, you wrote:
> 
> >Recently I had my first try at a UV-exposed board 
> >
> >(because I have nightmares from trying to align paper properly for a double-sided board with the laminator, ha ha)
> >
> 
> I figured that one out, or at least, got it very close to right.
> 
> use half thickness board, prepare each side individually.  Make sure
> that there are three alignment holes, each at a corner, leaving out
> one corner (keeps the board from being reversed).
> 
> I use map push pins and a slightly smaller drill.  You want a thick
> pin so it does not get pushed side to side by misalignment.
> 
> Harvey

Why half-thickness board? How do you get the board into a laminator with push-pins in it? I am not sure I understand how this would work, can you please explain?