Homebrew PCBs

Has anyone used the hydrogen peroxide plus hydrochloric acid to etch 
PCB's?

No, but I believe that ordinary, cheap Pool acid (HCL) works. It should work
really fast as well.

-----Original Message-----
From: caveteursus [mailto:j.walton@...] 
Sent: 14 October 2002 04:18 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] H2O2 + HCl + Cu


Has anyone used the hydrogen peroxide plus hydrochloric acid to etch 
PCB's?



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I thought HCL aka Pool Acid -was- Hydrocloric Acid. Isn't it?

Steve

--- stuart.lamble@... wrote:
> No, but I believe that ordinary, cheap Pool acid (HCL) works. It
> should work
> really fast as well.
> 
> > 
> -----Original Message-----
> From: caveteursus [mailto:j.walton@...] 
> Sent: 14 October 2002 04:18 AM
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] H2O2 + HCl + Cu
> 
> 
> Has anyone used the hydrogen peroxide plus hydrochloric acid to
> etch 
> PCB's?
> 
> 

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I've heard of it being used, but never tried it.I guess the best thing 
for you to do is try it yourself.
In Australia, H2O2 is available from commercial hair dressing suppliers 
in about 18% (wt) and sold in 250 ml to 5 liter. The HCl is brick 
cleaner, ect and available in most hardware shops, in anything from 
250ml to 25 liter and cheap too. HCl is almost always sold concentrated 
about 30 to 35% (wt). So going by the reaction

H2O2 + Cu + 2HCl -> CuCl2 + 2H2O

and 30%(wt) HCl =  8.2 Molar,  18% H2O2 = 5.3 Molar
for every mole of H2O2 you need two moles of HCl. i.e ratio of hardware 
store acid and hair dressing peroxide is approx.
volume acid * 8.2 = 2 * volume peroxide * 5.3
or
for every liter of 18% peroxide you need 5.3 * 2 / 8.2 = 1.3 liters of 
30% HCl solution.

I'd put a little more acid so that will make it nice even 1:1 volume 
ratio. Try undiluted and see how it works.
of course this is just my theory and you may actually need more acid or 
peroxide to get things moving quicker.


caveteursus wrote:

>Has anyone used the hydrogen peroxide plus hydrochloric acid to etch 
>PCB's?
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs
>
>To unsubscribe from this group, send an email to:
>Homebrew_PCBs-unsubscribe@yahoogroups.com
>
> 
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
>
>
>  
>

Hello caveteursus,

14. October 2002, 04:18:23, you wrote:

c> Has anyone used the hydrogen peroxide plus hydrochloric acid to etch 
c> PCB's?

  Of course, I'm usually using lower concentration of HCl (cca 16-18%) + 30%
  H2O2.  The  mixture  is approximative, i.e. if the etching reaction is too
  'bubbly'  add a little bit of acid, and if it is too slow, add little more
  H2O2.

  For real work I'm using the CuCl3+HCl combination, as it is never going to
  be thrown away (all excess of it I'm giving away to my colleges)

-- 
 Best Regards,
 Zoran
 mailto:zasto@...