Not sulphuric, muriatic acid and hydrogen peroxide.
It depends on what concentration of hydrogen peroxide you get. The simplest is 2 parts drugstore hydrogen peroxide and 1 part hardware store muriatic acid. The much weaker hydrogen peroxide means that no water need be added.
http://tech.groups.yahoo.com/group/Homebrew_PCBs/files/Etchants/Steve Greenfield AE7HD
--- In Homebrew_PCBs@yahoogroups.com, "pauldebono@..." <pawlud@...> wrote:
>
> What is the exact formula for making an echant, using hydrogen peroxide, sulpheric acid and distilled water please. Or has there been others ?
>