Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> It's very uniform and highly collimated, but is it strong enough?
>
I may have got lucky a couple of years ago. I used an old overhead 
projector with the original lamp installed as the exposure lamp / box. 
I placed the transparency on the projector, then the presentised 
circuit board and finally a book to hold it all down. I think I exposed 
the circuit board for 30 seconds and developed it. It came out perfect. 
I did learn a speck of dust also gets exposed into the pattern but an 
Xacto knife rimmed that away easily.

The first PC Board one I did using the Overhead projector, I had too 
much developer and saw the pattern develop then wash away. 

Gary K8IZ