Homebrew PCBs

Dylan Smith wrote:
> Basically, for registration, I use a bright light source (sunlight works
> well) and put the transfer sheets face to face, then use the light to get
> them lined up. PCB prints bold alignment lines to get it close - to get it
> perfect, I just line up the pins and vias. Then I tape the sheets together
> at one end to form a hinge, re-check alignment, and slip the board between
> the sheets and get ironing. Usually, registration is absolutely spot on
> using this method.

I take the extra step of sandwiching a small strip of pcb material between the
films using double sided tape. It gives a good edge for alignment and reduces
the errors from the film bending around the edge of the pcb. Then I tack the
film to the substrate using adhesive tape to stop anything moving while it's
exposed, inverted and exposed again.