> I've just done a bit of experimenting with the HCl I bought earlier, and
> some 20 Vol (6%) H2O2 from the local Boot's emporium.
>
> A couple of small pieces of PCB material about 1.5 cm in area etched
> completely in about 5 minutes at room temperature, with continuous
> agitation
> in a small container. I used about equal quantities of the 32% HCl and 6%
> H2O2. The resultant solution is now green, indicating that there are
> plenty
> of cupric ions present. If I re-use the solution, adding some H2O2 from
> time
> to time when it goes blue (excess CuCl2), I should end up with a
> reasonable
> concentration of CuCl3 that I can use. I think that some PCB manufacturers
> who use CuCl3 monitor the etchant by measuring the colour continuously and
> oxidise it automatically.
>
> Leon
> --
> Leon Heller, G1HSM
> leon_heller@...
> http://www.geocities.com/leon_heller
i find it strange that you didn't find hcl earlier.
it is very easy to get here....
i remember buying it long time ago when i was even too young to buy alcohol
and nobody asked a question.
it is sold here in many shops...
do you want to regenerate always with h2o2?
then i would suggest you stop air agitation.
because it is so volatile i think blowing air through it has only
disadvantages (like stirring coca cola).
the oxygen in the h2o2 is much more effective (i guess some 100 to 1000
times) than air oxygen.
you don't necessarily need to much hcl.
also don't add to much h2o2, it is soon lost after etching.
i use the smallest container which fits the pcb, so minimum etchand (h2o2)
is needed.
i think there is a important difference between cucl etching and hcl + h2o2
etching.
well, you can use h2o2 as a fast substitute for regenerating your cucl but
if you only put it in when etching (to have active h2o2 in the etchant when
the pcb is in) you will get much faster results because also the reaction to
cucl2 is used (not only cucl2 to cu2cl2).
i only guess that, but consider the following:
if you have fresh hcl and fresh h2o2 it also works fast, so it must work off
the solid copper without cucl2 present (yes, this is built instantly but for
t=0+ there is 0).
i think this is the explanation why it is so much faster.
also if you have a perfect regenerated cucl bath it is not so fast as if
there is h2o2 in.
if anyone here with enough knoweledge in chemistry may proof this (or proof
it wrong) i would very appreciate this.
regards
st
(in the moment i have problems with my harddisks. all two in my raid failed
- i know this is not likely due to the disks when both fail but other disks
work on the controller. bad week this.. the mishap with the printer, the
disks, my favourite tv station has changed encryption so i can't see anymore (it
it foreign so i don't get a legal card for it)... bad week, really bad week..
don't wonder if i miss some posts)
>
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