Homebrew PCBs

My jar of CuCl ?? was transparent emerald green(~55 Oz.). I put some 
more copper scraps in it and turned on the bubblier. It ran for 2 days. 
The contents of the jar turned DARK OPAQUE green.  I removed the solid 
copper scraps and started the bubblier again. I ran it 2 days and the 
contents of the jar was still DARK OPAQUE green. I added 2 Oz of HCL ... 
no change. I added 1 Oz of 27% H2O2 and the contents of the jar turned 
transparent emerald green. ... are we there yet ??
Jim KI6MZ

On 5/8/2011 4:49 AM, DJ Delorie wrote:
> "tda7000"<Tda7000@...>  writes:
>> So, I just have to keep adding a little hydrogen peroxide to
>> reactivate each time I etch until I've etched enough boards to turn it
>> dark, and then just bubbling will reactivate it?
> Until you've converted it, you still have an HCl/H2O2 etchant.  The H2O2
> breaks down over time, and the HCl evaporates, leaving you with just
> water.  So, if you're doing this over time, the thing to do is mix only
> enough HCl/H2O2 etchant for your board-du-jour, and keep adding it to
> your etchant tank.  Over time, the CuCl builds up, and you need less
> HCl/H2O2 for each board, and can start with the CuCl chemistry checks to
> see what you need (HCl or H2O2) each time you etch.  Also you can keep a
> chunk of copper in the etchant when you're not using it, so the excess
> HCl/H2O2 doesn't go to waste.  A copper plumbing part will do, like an
> elbow.  Just remember to take it out before adding the new etchant ;-)
>
> Remember, the etch does Cu + Cl =>  CuCl, so you have to have free Cl in
> the etchant also!  H2O2 alone is not enough.
>
>
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