Homebrew PCBs

I can't remember anything of use about the sulphuric acid thing.
What I do remember is that copper sulphate crystallizes out when the
etchant is cooled, which is neat, but for some reason I decided it is
not for me. I think it had to do with H2O2 stability but I'm not sure.

The discussion about it was here on this list, but years ago.

Regarding CuCl, if it has terrible fumes you do something wrong.

Most likely The Heating. Don't you ever heat CuCl unless to warm it up
from storage in a very cold room. HCl has a really low boiling point
(like 50C or something) and will fume like crazy even below that. Room
temperature is fine, it will take a few minutes but that should be OK.

A possible reason for fumes can also be too high HCl molarity, H2O2
should not be a problem unless you use a crazy amount.

I keep my CuCl in a covered, but not airtight tank, right next to a
lot of tools and steel items. There is no corrosion and no noticeable
odor. Even when etching with the air pump running there's no issue.

You should figure out what is wrong with your CuCl, I really doubt
sulphuric etchant is the answer. Do you know this already?
<http://members.optusnet.com.au/eseychell/PCB/etching_CuCl/index.html>

ST


On Wed, Jan 6, 2010 at 1:50 PM, Larry Battraw <lbattraw@...> wrote:

>
> 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
>
>