Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "Steve" <alienrelics@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, May 12, 2004 7:12 PM
Subject: [Homebrew_PCBs] Re: Blackening copper


> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> <stefan_trethan@g...> wrote:
> > Strange question, i know..
> >
> > any ideas how to chemically blacken the copper on a pcb (copper
> only, not
> > epoxy).
> >
> > For optical purposes, not electric. should be even colored.
>
> I found something at an art store a few years ago called "Liver of
> Sulphur" which I used to blacken copper for antiquing purposes.
>
> No idea what was in it, or where I have the bottle now to check. Google.

As someone else said, it's potassium sulphide. IIRC it's made by heating
potassium metal and sulphur. This could be dangerous, BTW.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller