--- In
Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> FeCl would normally be a light or dark tan color. Black or green means
> it's spent. The cheapest thing to try is to add some hydrogen peroxide
> to it, which will convert some or all of the dissolved copper into a
> cupric chloride etchant (emerald green). If that doesn't work, you'll
> have to add some hydrochloric acid, effectively making an acid/peroxide
> etchant that happens to have some spent FeCl in it.
>
> I've used old etchant that wasn't spent and it works just fine; it's not
> the age that counts it's how much you've used it.
>
FeCl also works best Heated. I would really recommend the Cupric Cholride, it works great. I use to use FeCl but now that I use Cupric Cholride I'll never use FeCl again. Cupric Cholride also does great just at room temp. so no heating.
Ben