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FeCl + citric acid = Edinburgh Etch; HCl is transparent?

FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-23 by Robin Whittle

In the past I used Ferric Chloride.  My recent PCB-DIY adventures are
just beginning.  At present I am using a mixture of ferric chloride and
citric acid, which is widely known as Edinburgh Etch.

I followed this material:

  http://www.nontoxicprint.com/etchcopperandbrass.htm

   "4 liters ferric chloride solution + 1 liter hot water mixed with
    300ml citric acid powder (ratio 3:1) = Edinburgh Etch"

This is citric acid powder by volume.  To make half of my Ferric
Chloride in this way I need 1/16th of this.  So my mixture is:

  250ml Ferric Chloride solution from http://www.altronics.com.au
  62.5ml hot water mixed with 18.75 ml by volume of citric acid powder.

I have little experience with this so far.

In the "Magnetic drive pumps for spray etchers" thread Derward Myrick
wrote that he uses muriatic acid (HCl, hydrochloric acid) because he can
see the board as it etches.

I guess the topic of etchants has been discussed many times.  Does
anyone have any views on Edinburgh Etch?  There are claims that it can
have a very long life.

Is hydrochloric acid used on its own, with dilution with water, or with
hydrogen peroxide (H2O2)?

  http://joshuagalloway.com/pcb.html

   Two parts 3% H2O2 to one part 31.5% HCl.

I imagine the transparency of the etchant would be helpful.  However,
does the etching process leave a residue on the board?  I think one of
the claims about Edinburgh Etch is that it doesn't leave any residue.


- Robin         http://www.firstpr.com.au/pcb-diy/


  - Robin

Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-23 by tda7000

That would be the one http://joshuagalloway.com/pcb.html 

If I click the link from the post it redirects me to somewhere entirely different (http://cyber-shop.net/), and Google warns about malware.

But very strangely, if I copy the URL and enter it manually, it works fine.


--- In Homebrew_PCBs@yahoogroups.com, Kevin Byrne <kbyrne10@...> wrote:
Show quoted textHide quoted text
>
> One of links on this page produced a warning not to be ignored about hackers. Be advised Kevin
> 
> [Non-text portions of this message have been removed]
>

Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-23 by Donald H Locker

The rogue link carries a trailing space character " " (%20) Best to enclose hyperlinks in <http://joshuagalloway.com/pcb.html> so that the browser or email program doesn't split the link or combine other bits into it.

Donald.
--
*Plain Text* email -- it's an accessibility issue
()  no proprietary attachments; no html mail
/\  ascii ribbon campaign - <www.asciiribbon.org>

----- Original Message -----
Show quoted textHide quoted text
> From: "tda7000" <Tda7000@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, August 23, 2012 6:32:49 AM
> Subject: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?
> That would be the one [Rogue link excised]
> 
> If I click the link from the post it redirects me to somewhere
> entirely different (cyber-shop dot net is a bad hat too), and Google warns about
> malware.
> 
> But very strangely, if I copy the URL and enter it manually, it works
> fine.
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, Kevin Byrne <kbyrne10@...>
> wrote:
> >
> > One of links on this page produced a warning not to be ignored about
> > hackers. Be advised Kevin
> >
> > [Non-text portions of this message have been removed]
> >
>

Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-23 by Donald H Locker

Sorry to followup to my own post, but I discovered the <> didn't work right either. Something suspicious here. Beware.

--
*Plain Text* email -- it's an accessibility issue
()  no proprietary attachments; no html mail
/\  ascii ribbon campaign - <www.asciiribbon.org>

----- Original Message -----
Show quoted textHide quoted text
> From: "Donald H Locker" <dhlocker@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, August 23, 2012 8:13:37 AM
> Subject: Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?
> The rogue link carries a trailing space character " " (%20) Best to
> enclose hyperlinks in "<>" so that the
> browser or email program doesn't split the link or combine other bits
> into it.
> 
> Donald.
> --
> *Plain Text* email -- it's an accessibility issue
> () no proprietary attachments; no html mail
> /\ ascii ribbon campaign - <www.asciiribbon.org>
> 
> ----- Original Message -----
> > From: "tda7000" <Tda7000@...>
> > To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> > Sent: Thursday, August 23, 2012 6:32:49 AM
> > Subject: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch;
> > HCl is transparent?
> > That would be the one [Rogue link excised]
> >
> > If I click the link from the post it redirects me to somewhere
> > entirely different (cyber-shop dot net is a bad hat too), and Google
> > warns about
> > malware.
> >
> > But very strangely, if I copy the URL and enter it manually, it
> > works
> > fine.
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, Kevin Byrne <kbyrne10@...>
> > wrote:
> > >
> > > One of links on this page produced a warning not to be ignored
> > > about
> > > hackers. Be advised Kevin
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >

Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-23 by Kevin Byrne

Understood  thanks I am not a expert but Google advise I listen to & back off. Kevin


________________________________
Show quoted textHide quoted text
 From: Donald H Locker <dhlocker@...>
To: Homebrew PCBs <Homebrew_PCBs@yahoogroups.com> 
Sent: Thursday, August 23, 2012 7:16 AM
Subject: Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?
 

  
Sorry to followup to my own post, but I discovered the <> didn't work right either. Something suspicious here. Beware.

--
*Plain Text* email -- it's an accessibility issue
()  no proprietary attachments; no html mail
/\  ascii ribbon campaign - <www.asciiribbon.org>

----- Original Message -----
> From: "Donald H Locker" <dhlocker@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, August 23, 2012 8:13:37 AM
> Subject: Re: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch; HCl is transparent?
> The rogue link carries a trailing space character " " (%20) Best to
> enclose hyperlinks in "<>" so that the
> browser or email program doesn't split the link or combine other bits
> into it.
> 
> Donald.
> --
> *Plain Text* email -- it's an accessibility issue
> () no proprietary attachments; no html mail
> /\ ascii ribbon campaign - <www.asciiribbon.org>
> 
> ----- Original Message -----
> > From: "tda7000" <Tda7000@...>
> > To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> > Sent: Thursday, August 23, 2012 6:32:49 AM
> > Subject: [Homebrew_PCBs] Re: FeCl + citric acid = Edinburgh Etch;
> > HCl is transparent?
> > That would be the one [Rogue link excised]
> >
> > If I click the link from the post it redirects me to somewhere
> > entirely different (cyber-shop dot net is a bad hat too), and Google
> > warns about
> > malware.
> >
> > But very strangely, if I copy the URL and enter it manually, it
> > works
> > fine.
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, Kevin Byrne <kbyrne10@...>
> > wrote:
> > >
> > > One of links on this page produced a warning not to be ignored
> > > about
> > > hackers. Be advised Kevin
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >

 

[Non-text portions of this message have been removed]

Re: [Homebrew_PCBs] FeCl + citric acid = Edinburgh Etch; HCl is transparent?

2012-08-24 by DJ Delorie

HCl alone is transparent, but HCl alone will *not* etch copper.  It
needs an oxidizer.  Any oxidizer will do, but H2O2 (peroxide) is dirt
cheap and readily available, so it's the oxidizer of choice.  In a CuCl
etch (the opaque green stuff), the CuCl itself (when green) is the
oxidizer.

The life span of an etchant depends on two things: (1) how much of the
"donor" material is used up, and (2) how fast volatiles evaporate or
decay.  In an HCl etchant, the chlorine is both used up by the etch and
can evaporate, and the H2O2 breaks down over time.  A CuCl etchant lasts
longer but you still need to add O2 (air) and HCl as they're depleted.
Any FeCl etchant will be "used up" over time, but in general won't "go
bad" due to evaporation or breakdown.  I have some FeCl etchant that's a
few decades old that still works.