--- In Homebrew_PCBs@yahoogroups.com, Russell Shaw <rjshaw@...> wrote: > > On 23/03/12 02:07, sheldon_mp_cooper wrote: > > --- In Homebrew_PCBs@yahoogroups.com, Russell Shaw<rjshaw@> wrote: > >> > > >> The deep olive colour is when to add HCl and use as a long-term etchant. > > > > But, at that point, highly dangerous chlorine gas WILL be generated from the > > reaction, as was warned about in the other link I referred to where the gent > > said he'd used the same etchant for four years. > > Adding a cup of HCl to a litre of spent or unspent ferric chloride will cause absolutely no outgassing whatsoever. Well, I guess you must be speaking from experience and I haven't done this myself, but this gent who has says it will: http://www.qsl.net/iz7ath/web/02_brew/14_howto/02_clor/index.htm Excerpt: "It's necessary to regenerate it; 1)At first it's necessary to raise the acidity, adding hydrochloridic acid HCl (you'll find at shop as muriatic acid, mixed with water.....ask mum); make this work in a open place (DANGEROUS GAS) addig HCl until the muddiness in the tank disappears (or you can also use a litmus paper)."
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Re: Rejuvenating ferric chloride etchants
2012-03-23 by sheldon_mp_cooper
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