31% HCL, also known as Muriatic Acid. A standard strength I buy at just about any hardware/building supply store. Also available at pool supply stores.
--- In Homebrew_PCBs@yahoogroups.com, DaveC <davec2468@...> wrote:
>
> What strength hcl are you using? The ratio is easily understood, but
> it all depends on the strengths. (I see you use 3 percent h2o2.)
>
> Thanks
> Dave
>
> -=-=-=-
>
> >I use this technique all the time. I can do a 4X6 inch board in
> >about 2 minutes. I use 1 Part HCL and 2 Parts 3% H2O2. I make just
> >enough etchant to cover the board about 1/8 to 1/4 inch and lightly
> >brush the surface with a foam Paint brush. I etch at room
> >temperature. Works very well for me.
> >
> >I've also tried 1 part HCL and 2 parts 12% H2O2 but the reaction was
> >too fast and hot to control easily.
> >
> >
> >
> >--- In Homebrew_PCBs@yahoogroups.com, "tda7000" <Tda7000@> wrote:
> >>
> >> I see some people get very fast etch times with a sponge and
> >>ferric chloride...
> >>
> >> But has anyone tried that method with the HCl and H2O2 solution,
> >>or the cupric chloride?
> >>
> > > Or anything else for that matter?
>