That site put me on the trail of sodium perborate. It is unclear how he is using it. If you want hydrogen peroxide then you need to dissolve it in water. The crystals are a source of active oxygen so maybe this is all you need with the acid. I never really followed up on this. I am using the Edinburgh etch version of ferric chloride for my boards.
Baxter
--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" <javaguy11111@...> wrote:
>
> Interesting. From this site
>
> http://catmacey.wordpress.com/projects/making-pcbs-with-simple-tools/etching-the-board/
>
> it looks like sodium perborate tetrahydrate can be used with HCl/muriatic acid to etch boards as well. I sort of like this idea better than using HCl and H2O2.