Homebrew PCBs

I don't get anything reliable smaller than 6.6mil either. I too
believe it might be possible, but i don't need it and i like the
reliability i have with wider traces.

That looks like medical H2O2 there. I thought medical solution
contained too much water for CuCl etching?

Does the sink really drain to groundwater? I don't think any sink
should drain straight to groundwater ;-)

ST



On Sun, Mar 16, 2008 at 2:49 AM, DJ Delorie <dj@...> wrote:
>
> I finally collected enough bits and pieces to do CuCl etching
> (although it's still HCl etching).  I've been collecting stuff for
> quite some time now, HCl, H2O2, NaOH, beakers, etch tank, hydrometer,
> etc.  Also built a separate chemistry bench with a vent fan and sink.
>
> I also took the time to do a "print survey" of all my laser printers
> (I've got three functioning ones at the moment) and toner cartridges
> (three for one of the 4P's) to find the best one.  Turns out the old
> HP 4P produces much crisper prints than the new (and faster) HP 2550.
> I suspect it's a combination of "black only" and "slower path".
>
> Anyway, I etched my bloat board, which I've mentioned here before.  It
> is just a grid of various line/space samples, with tweaks
> (bloat/shrink) to the lines to try to compensate for the process.  My
> goal was to get a reliable 5/5 etch, but I'm not quite there yet.  The
> solution is a faint green now!  :-)
>
> The 6.67/6.67 rules seem to have worked reliably, although everything
> was over-etched (new HCl solution).  The 5/5 rules were barely
> passable if I shrunk the traces by a pixel (i.e. 3.33/6.67 rules).
> The regular 5/5 pattern had a few shorts in it.  I haven't tried
> 5/6.67 rules yet.
>
> Photos at http://www.delorie.com/pcb/lab/
>
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