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Subject: Re: [Homebrew_PCBs] Re: muriatic and H2O2 -goods and bads ?

From: Stefan Trethan <stefan_trethan@...>
Date: 2004-03-24

>
> From what you've written above, I would think that the h202 is just a
> means to get oxygen into the HCL, so a bubbler/sparger and HCL is the
> ticket? (with the usual concerns about muriatic vapors)
>
> Thank you in advance for any clarification,
>
> Ballendo
>

Yes it works with only a bubbler.
However it is much easier and faster to use H2O2. it is so cheap i do not
really care.
Also i want no fumes from the bubbler because i store it in a room with
loads of tools and i
do not want corrosion (the bubbler has to run long times to get enough air
in).

It stays clear enough to see the board through it.

I also noticed that with a little bit of excess H2O2 the etching itself is
faster (maybe
the Cu2Cl2 is instantly reduced back to CuCl2 by the excess H2O2, i do not
know.)


H2O2 is a very easy, clean way to get the oxygen in. 100% H2O2 has about
1,4kg that means
there is half a kg oxygen solved in there, or not?

O weighs 22g/mol, so .4 kg is 18 mol. (it is only 35% H2O2 so let us
calculate with 6mol

Cu weighs ? 60g/mol, so with the above O you could theoretically convert
360g copper.
it weighs 9g/ccm which means that are 40ccm and with 35u copper thickness
that are 1,1 square
meter with one bottle H2O2 35%..

would be 62 100mmx160mm single sided.

Not sure if this calculation makes any sense at all..

ST