Homebrew PCBs

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/

Thats some pretty fine etching there.

Daryl.

--- In Homebrew_PCBs@yahoogroups.com, 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/
>

"logicresearch" <logicresearch@...> writes:
> Thats some pretty fine etching there.

Thanks.  I think the printer can do better, though.  It's very
sensitive to the paper you print on.  For example, printing on a
transparency gave very crisp edges, *but* there were drop-outs due to
dirt on the transparency, and my attempts to clean it only made the
results worse.  I'm using Pulsar's paper at the moment, when that runs
out I might try press-n-peel to see if my printers like it better.  I
also haven't tried adding Pulsar's green film with the HCl bath; these
results were with just toner.

I do still recommend rehydrating any paper you print on, it seems to
consistently help.

I'm also looking forward to experimenting with the photofilm I got;
maybe that will produce a more reliable edge.

The other thing I haven't figured out is how to get my color laser
printer to overlap all its toners to get a really thick coating.  It
seems to ignore the relevent commands I send it and do what it thinks
is right :-(

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/
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

"Stefan Trethan" <stefan_trethan@...> writes:
> That looks like medical H2O2 there. I thought medical solution
> contained too much water for CuCl etching?

It's a 3% solution.

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

It drains into the perimeter drain for the basement, hence the sign.
The pipe eventually ends up draining out in the woods downhill of the
house, which is technically groundwater.  It's not ideal, but the
septic lines are a couple of feet higher than the sink - not that I'd
want that stuff in my septic tank.  Tanks have living biomass in them,
you know.

Mostly I wanted a source of water (hot and cold).  I use plain water
for my woodworking stuff also.  I can also keep the water running
while playing with the chemicals, in case something bad happens I can
do a quick rinse.

As for the rest of the chemicals - even if I rinse the pcb's off in it
after etching, the amount of copper that goes in there is less than
what my copper pipes are putting into the ground, and we've already
got a ton of iron in the ground anyway.  There is sufficient distance
between the outlet and other water systems to provide filtration.

To top it all off, my wife works for a company that does water
systems, and she says it's acceptable.  The sign is mostly to keep out
woodworking stuff, like solvents, stains, paint thinners, oil
finishes, etc.

yes sure the ground will filter it just fine, we are talking tiny
quantities for rinsing.

I would have expected it to read "surface water" not "ground water" in
such a situation as yours. Understand it now.


ST

On 16 Mar 2008 12:07:46 -0400, DJ Delorie <dj@...> wrote:

>
> It drains into the perimeter drain for the basement, hence the sign.
> The pipe eventually ends up draining out in the woods downhill of the
> house, which is technically groundwater.  It's not ideal, but the
> septic lines are a couple of feet higher than the sink - not that I'd
> want that stuff in my septic tank.  Tanks have living biomass in them,
> you know.
>
> Mostly I wanted a source of water (hot and cold).  I use plain water
> for my woodworking stuff also.  I can also keep the water running
> while playing with the chemicals, in case something bad happens I can
> do a quick rinse.
>
> As for the rest of the chemicals - even if I rinse the pcb's off in it
> after etching, the amount of copper that goes in there is less than
> what my copper pipes are putting into the ground, and we've already
> got a ton of iron in the ground anyway.  There is sufficient distance
> between the outlet and other water systems to provide filtration.
>
> To top it all off, my wife works for a company that does water
> systems, and she says it's acceptable.  The sign is mostly to keep out
> woodworking stuff, like solvents, stains, paint thinners, oil
> finishes, etc.
>

"Stefan Trethan" <stefan_trethan@...> writes:
> I would have expected it to read "surface water" not "ground water" in
> such a situation as yours. Understand it now.

I suppose I could re-print the sign, but it's mostly there to keep
visitors from complaining.  *I* know where the drain goes :-)

Hey, worst case, the chemicals will keep the weeds from overgrowing
the drain pipe outlet!  I've got to clean that area out every year
anyway.