Homebrew PCBs

Thanks .. thats a great tool .. 
Helps a lot .. 
ok .. so I am going to cut the H2O2 solution again, down to 10 ish percent.. 
Question .. if I mix equal proportions of hydrogen peroxide, one being 3 percent and another being 35 percent .. whats the end result? I know it may not be as simple as averaging .. thats the mix that I called 17 percent .. but I see what you mean about the etchant mix I had started with .. too much oxygen there .. say one thing though .. never ever seen a board etch in less than one minute like that before.. holy crap .. 
Thanks again for the help and the calculator.

Randy

--- In Homebrew_PCBs@yahoogroups.com, Erik Knise <elknise@...> wrote:
>
> Randy, with 17% H2O2 and 34% HCL the ratio is about even for the
> reaction.  With 3% H2O2 and 34% HCL you need about 5 times as much
> peroxide as HCL.
> 
> You can use the calculator I wrote to play with the numbers:
> http://www.totse2.com/easy-e/cupricchloride.html
> 
> -- 
> Erik L. Knise
> Seattle, WA
> 
> On Sun, Apr 10, 2011 at 2:49 PM, Harvey White <madyn@...> wrote:
> > On Sun, 10 Apr 2011 19:40:39 -0000, you wrote:
> >
> >>ok .. thanks Harvey ..
> >>Does it also change color when it calms down?
> >>When I added more 3% peroxide .. it changed color..
> >>and slowed down the etching process immensely.
> >>Didnt seem like I added all that much either..
> >
> > As I remember, it started clear, then turned light and transparent
> > green.  As the etchant changes, it goes to an olive color/dark green.
> > The 17% peroxide was more than needed, it is usually mixed in that
> > ratio using 3%.
> >
> > You diluted it a bit, and that probably needed to be done.
> >
> > Adding more peroxide later will tend to turn it transparent green.  As
> > it ages, it does need oxygen to make the reaction run, that's the
> > function of the peroxide.
> >
> > Harvey
> >
> >>
> >>
> >>--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@> wrote:
> >>>
> >>> On Sun, 10 Apr 2011 10:57:23 -0700 (PDT), you wrote:
> >>>
> >>> >ok .. 17% peroxide ..
> >>> >34 % muriatic acid ..
> >>> >mixed 3 : 1 ..
> >>> >never seen copper come off a board that fast .. ever ..
> >>> >did it outdoors .. respirator .. goggles .. gloves ..
> >>> >anyways.. should the solution be bubbling even AFTER I take the
> >>> >board out ?? whats it mean .. I put more 3 % peroxide in it ..
> >>> >calmed it down ..  is it safe?
> >>>
> >>> The peroxide is going to decompose and release oxygen, that's what you
> >>> see.  It will calm down in about 30 days to the point where it doesn't
> >>> want to do much.
> >>>
> >>> Regenerate it by bubbling oxygen through it.  It eventually changes to
> >>> a different kind of etchant, takes longer, is  a bit more mild in
> >>> terms of action.
> >>>
> >>> Nothing to worry about in the proportions you used.
> >>>
> >>> Harvey
> >>>
> >>> >
> >>> >Randy
> >>> >
> >>> >
>