Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Jamie Lyon" <aeonflame@...> wrote:
>
> Hi all,
> 
> I'm currently etching with Ammonium Persulfate, but having to heat it
> up isn't very easy, so I want to give etching with hydrochloric acid +
> hydrogen peroxide a go.
> 
> I've managed to get hold of the acid in the form of brick cleaner, it
> doesn't specify the percentage, but I'm assuming it's somewhere around
> 30%, which seems to be standard.
> 
> The hydrogen peroxide however I had quite an issue getting hold of
> (I'm in the UK), I've managed to get some medical grade (3%) stuff
> from a local supermarket, however it mentions other extra contents on
> the label, phosphoric acid & phenacetin. I'm not sure what the volume
> of those additives are, as it doesn't mention it on the label. Would
> they possibly cause an issue? I don't want it blowing up in my face
> when I mix it :)
> 
> Finally, I've seen several mixes on the net -- with the medical grade
> peroxide, does 2:1 peroxide:acid sound about right?
> 
> Many thanks,
> Jamie
>

I use Muriatic acid and H2O2 ( medical grade 3% too ) with good
results. The only problem is, after some days i can´t really etch with
it, i must throw it away and make a new one, i don´t know why, i don´t
understand chemistry ...
I use 3:1 ( 3 of H2O2 and 1 of Muriatic acid ), it´s quite fast, about
5 to 10 minutes at room temperature (+/- 20ºC ).

Sam