Homebrew PCBs

Here's a web page about using the acid/peroxide etchant. About half way down the page is a calculator for the mix. Input your % acid and % peroxide and it tells you how much water you have to add. 

http://www.dr-lex.be/hardware/tonertransfer.html

--- In Homebrew_PCBs@yahoogroups.com, DaveC <davec2468@...> wrote:
>
> >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.
> 
> I'm using the same effective ratio. My muriatic is 15% and h2o2 is 3% 
> and my ratio is 1:1.This is the same as you're using: 31% hcl and 3% 
> h2o2 at a ratio of 1:2.
> 
> I'm still not sure why my etching takes so long.
> 
> >  > >I've also tried 1 part HCL and 2 parts 12% H2O2 but the reaction was
> >>  >too fast and hot to control easily.
> 
> I'm confused: you use LESS hcl and the reaction was faster? I thought 
> the acid is what increased (using more) or decreased (using less) the 
> speed of the reaction, no?
> 
> Thanks,
> Dave
> 
> -=-=-=-
> 
> >--- 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?
>