--- In
Homebrew_PCBs@yahoogroups.com, Adam Seychell <a_seychell@y...> wrote:
> gettingalongwouldbenice wrote:
>
> >
> > In the files section are instructions for
> > making etchant from muratic acid and hydrogen peroxide.
> >
> > Sounds like something interesting to try.
> >
> > As I understand it, you stick in the board and the copper goes
> > into solution. You regenerate the solution by bubbling air
> > through it. Ok, so where does all that copper go when you regenerate???
> > Thanks, mike
> >
> >
> Thats not the full story, the regeneration reaction consumes both oxygen
> (from air) and free hydrochloric acid. Overall it is;
>
> CuCl + O + 2HCl -> CuCl2 + H20
Chemistry is good...but...let's do a thought experiment.
Keep etching and regenerating until you've etched a ton of copper
in your pint of etchant. The copper can't still be in solution.
Where is it?
If it's using up the HCl, then we need to add HCL??? Which means
it ain't regenerating by air alone??? Looks like need to add
HCl. then there's too much water, so gotta add more H2O2.
Which is what we had to do to make the stuff in the first place.
So, "regeneration" don't seem to be adding any value?????
Still confused,
mike