The problem with air bubbling is that you need enough CuCl in there to
finish the board (and then some). Otherwise you'd need to re-generate
during etching, which i think would be very slow. The advantage of
H2O2 is that any excess stays in the tank, at least for a short while,
available to immediately regenerate any CuCl. This means you can etch
a board even if there is not enough CuCl in the tank, and it allows to
"build up" CuCl by etching PCBs (which i would consider very
impractical with air bubbling alone).
ST
On Tue, Jun 17, 2008 at 11:30 PM, Herbert E. Plett <cachureos@...> wrote:
> the bubbler running will provide for some of the needed O2.
> perhaps a little more HCl is needed, it also fumes out...
>
>
>
> --- On Tue, 6/17/08, DJ Delorie <dj@...> wrote:
>> I've got a somewhat new tank of HCl etchant that
>> I've used a few
>> times, but it's mostly been sitting for a while.
>> It's only pale
>> green, but it's emerald not brownish. My test boards
>> (one just
>> scrubbed copper as a control) have been in it for 40
>> minutes now.
>> It's warm and the bubbler is running, I even added a
>> shot of peroxide
>> ten minutes ago. It etched real quick the first time I
>> used it, when
>> it was fresh.
>>
>> What's the most likely cause of this sluggishness?
>> What could I try
>> doing? Things to test?
>>
>> I was thinking of making some copper oxide (the wire+heat
>> trick) and
>> try to get the solution darker, but I'd rather not put
>> too much copper
>> in if there are simpler ways.
>
>
>
>
>
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