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From:	karl AT aspodata DOT se
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] DIY PCBs
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Comments:	In-reply-to "John Griessen (john AT ecosensory DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
	message dated "Sat, 17 Jun 2017 16:38:47 -0500."
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Date:	Sun, 18 Jun 2017 17:37:03 +0200 (CEST)
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John Griessen:
> On 06/17/2017 03:11 AM, John Conover wrote:
...
> > http://www.johncon.com/john/PCB/
...
> I also use air regeneration of the CuCl2, which might even reduce the amount of HCl needed,
> but that's not a very big cost anyway.  It does skip the need for any H2O2 buying
> except to get started quickly.   Air bubbling of copper wire under HCl will get you
> a charged up  CuCl2 bath eventually.  DJ Delorie gets credit for the CuCl2 chemistry
> efficiency details.

I usually use natriumperoxidisulfate for etching, would there be any
advantage to use H2O2/HCl instead ?

///

I found a comparision of etching baths re. danger in [1] which
says that H2O2/HCl produces toxic gases.

[2] says that natriumperoxidisulfate can produce finer structures
than Fe(III)Cl.

[3] proposes citric acid (sounds very slow).

[4], p. 7 indicates that Fe(III)Cl is 6 times faster than H202/HCl, and
peroxidifulfate is inbetween (3600 / 2500 / 600 nm/min).

[5], uses Acetic Acid and Hydrogen Peroxide and is a little slower 
(200nm/min).

[6] states that perdisulphate is cleaner and safer than Fe(III) and
H202 variants.

Has anyone tried electrolysis as in [7], [8] ?

[9] uses CuCl which can be regenerated, but has more undercut according
to [10].

Regards,
/Karl Hammar

[1]  https://web.archive.org/web/20090907183632/http://www.tuf-ev.de/workshop/aetzen/EntsorgungAetzen.htm
[2]  https://de.wikipedia.org/wiki/Natriumpersulfat
[3]  http://transene.com/wp-content/uploads/Copper-Etch-Article.pdf
[4]  https://nanolab.berkeley.edu/labmanual/chap1/JMEMSEtchRates2(2003).pdf
[5]  http://engineering.tufts.edu/microfab/documents/SOP_CopperEtch2.pdf
[6]  http://sfprime.net/pcb-etching/
[7]  http://nontoxicprint.com/electroetching.htm
[8]  https://en.wikipedia.org/wiki/Electrolysis
[9]  http://www.goldrecovery.us/goldrecovery/documents/CuCl.pdf
[10] http/www.chemcut.net/wp-content/uploads/2015/03/Chemcut_Bulletin_8_Cupri_Chloride_Proces_-Parameters.pdf

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