Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Wed, 19 Apr 2006 20:53:14 +0200, Steve <alienrelics@...> wrote:
> 
> > Looking up where to find Tarn-X, I found out that the chemical in it
> >
> > can be bought for next to nothing.
> >
> >
> > http://www.ganoksin.com/orchid/archive/200305/msg00153.htm
> 
> 
> This one says it's thiourea!
> 
> "Toxic. Known animal carcinogen and probable human carcinogen."
> 
> And they still sell it in the US? Does it carry a health warning?

The link I gave agrees with you:
"It's Thiocarbamide, also known as Thiouria."

Since it is -not- an acid but rather something to convert sulfides
back to pure copper, it may simply be enough to make sure you scrub
down to pure copper. That's what I'm going to try.

BTW, I vaguely recall someone telling me that liquids with a base pH
will tend to strip water based inkjet inks. So it may be important to
use FeCl. I had hoped to stop using FeCl, so I'm anxiously awaiting
the trials of other etchants.

Steve Greenfield