Homebrew PCBs

Hi Leon,

>I've just made another PCB with a footprint for a Hirose 50 way DF12
>connector with 0.5 mm lead spacing, it turned out very well. The DF12
>pads are 0.38x1.00 mm.
>  
>
That's very impressive! It's pretty much what I'm aiming for, but I just 
can't seem to get my process right. It's good to see some results in 
context: I often find that people advocating one method or another 
without revealing the level of complexity (principally trace and space 
width) that they're attempting.

I'd like to be able to make double-sided boards with 8/8 traces and 
spaces but this seems problematic. I'd be interested to hear from anyone 
who's done this! My two biggest problems are contamination of the board 
while handling it between stages of the process, and alignment between 
the two layers. I need aligment errors of less than 1mm, and I'm not 
sure that this is achievable in a DIY set-up. At the moment I drill 
guide holes before exposure and use PCB pins to tack each side of 
artwork in place, in turn, before taping the artwork to the board and 
placing it in my UV box.


Stuart