Homebrew PCBs

----- Original Message ----- 
From: "Russell Shaw" <rjshaw@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, May 15, 2004 8:10 AM
Subject: Re: [Homebrew_PCBs] Re: Blackening copper


> Leon Heller wrote:
> > ----- 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.
>
> Maybe reacting potassium hydroxide with sulphuric acid could give
> something.

That will give potassium sulphate, not the sulphide.

Leon