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Subject: Re: [Homebrew_PCBs] Dry film tenting problem & pattern plating

From: Larry Battraw <lbattraw@...>
Date: 2010-01-06

On Wed, Jan 6, 2010 at 4:09 AM, Stefan Trethan <stefan_trethan@...> wrote:
>
>
>
> Hi,
>
> I think only the sulphuric acid / hydrogen peroxide etchant will work
> with tin as reisist.
> It is similar to CuCl but has the disadvantage of not keeping as well,
> requiring more maintainance.
>
> I think gold would work as a resist for the other etchants, but is
> slightly more expensive ;-)
>
> ST

Hi Stefan, I've been working CuCl etchant recently and really had
problems with the terrible fumes it puts off, particularly when it's
heated so it will actually etch a board.  Can you explain a little
about the disadvantages of Sulfuric/Peroxide etchant and how to
maintain the etchant bath?  Sulfuric acid seems so much less harsh
when it comes to fumes and I would like to try it. Do have any
suggestions for the concentrations or PH of the solution to make it
work?

Thanks-
Larry