Homebrew PCBs

I'm using 30% H2O2, not 3%, but I have to do some calculations to 
compare the two.

Mark


At 05:11 PM 3/18/2010, you wrote:
>Mark, I am a long way from being an expert, but until one of the 
>experts chips in, I'll say that the proportions don't sound right to 
>me. I use 1 part 30% HCl, and 2 parts 3% H2O2, and it etches 
>quickly. So it would seem that you are using a way, way higher 
>concentration of H2O2 to HCL -- ??
>
>FWIW, even though this mixture etches quickly, it does etch from the 
>outside edges in -- but that is true of every etching I have seen or 
>done, not that that is a very large sample.
>
>--- In Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:
> >
> > It's Claroxide 30, from a beauty supply, and should be fresh. Perhaps
> > I'm using too little - I used 30 cc water +30cc HCl +10cc H2O2 for a
> > ds board that measured about 4x2 inches. I don't know the thickness
> > of the copper. The board was etched horizontal in a container with
> > the etchant level only about .25 inches above the surface of the board.
> >
> > Mark
> > \
> > At 12:35 PM 3/18/2010, you wrote:
> > >Is the H2O2 fresh?  It breaks down over time, a solution that's been
> > >mixed for a while won't have any H2O2 left in it, and HCl won't etch Cu
> > >without an oxidizer.
> > >
> > >Are you sure you used 30% H2O2 and not the more common 3% ?
> > >
> > >
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>
>
>
>------------------------------------
>
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