I found: expose, develop, drill, etch worked best for me. When I
drilled after etching, I always seemed to screw up some pads.
Undoubtedly I was using too low an RPM or inadequate bits. However, I
never had problems drilling before etching. Gave much more room for
error.
-tdi
--- In Homebrew_PCBs@yahoogroups.com, "sciciora" <ciciora@C...> wrote:
> I just tried drilling a PCB before exposing it, and it didn't seem
> like a better method. Spinning carbide drills at 30k rpm, the green
> photosensitive coating flaked off near the holes. Just like
sheering
> the boards before exposing them. So, I think for the near future,
> I'll expose, develop, etch, _then_ drill.
>
> Does anyone know for how long they are photosensitive? Are they
> still sensitive after develping? Do I have to etch in the dark?
>
> Thanks!
>
> - Steven Ciciora