Even the Ferric Chloride etchant will etch unevenly and take some time in
cold etchant. Is CuCl the same? I have always heated the Ferric but am
wondering if this is the thing to do with the CuCl.
-Mike
----- Original Message -----
From: "Francisco Peña" <mute@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, May 06, 2003 10:00 AM
Subject: Re: [Homebrew_PCBs] First pcb etched with CuCl
> I have experienced uneven etching using CuCl too. I etch my boards
horizontally facing up, and the etching happens from the edge to the center
of the board, and takes about 30minutes to have an 8x6" board done. The end
result is perfect and the traces look fine, although I'm a bit concerned
about the time too. I think my mix needs more oxigen too.
>
> Fp
> www.tonepad.com
>
>
>
>
> ----- Original Message -----
> From: grantfair2001
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Sunday, May 04, 2003 9:59 PM
> Subject: [Homebrew_PCBs] First pcb etched with CuCl
>
>
> Even though my tank of etchant is far from the deep green color which
> shows it is at an optimum, I decided to etch a small board tonight. I
> hung it in the etchant above the aerator. (I drilled a hole in one
> end and hung it from an insulated wire).
>
> In about 25 minutes one half (the part closest to the etchant surface)
> was etched clear. It took another 25 minutes to get the other half
> clear. I finally had to hang it upside down to get it cleared. A
> horizontal pcb holder is in the planning stages.
>
> In the first 20 minutes or so, I noticed part of the copper on the PCB
> was light grey in color. I suspect this was CuCl(I) because when I put
> a small amount of green etchant from the tank lid on this area, it
> disappeared. This also suggests that there is lots of CuCl(I) still in
> solution.
>
> I measured the pH again with indicator paper. The paper showed red (2)
> after I emptied the second 4 litre jug of HCl into it a few days ago.
> However, today it was 3 (or higher, if the the pH is higher yet and
> the etchant is discoloring the indicator paper).
>
> Although there is green etchant on the inner surface of the tank top,
> a drop of tank etchant dropped on the same lid is dark brown. So a lot
> of CuCl(I) needs to be converted. I am waiting for some fine bubble
> diffuser hose. Unfortunately most fish farming is done on the east and
> west coasts of Canada, and I am more or less in the middle between the
> two.
>
> So things are progressing, if slowly, I am learning about the CuCl
> approach, and I have etched my first board. In spite of the long dunk
> it looks just fine with all traces intact. Because I haven't had a
> totally clear recipe to operate from, things have gone slowly. But I
> hope my experience will make it easier for anyone who wants to use
> this appraoch in the future.
>
> Grant
>
>
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