Well, the CuCl2 etching is basically what is happening in
your solutions, the difference between the etching technique
discussed recently on this group and the H2O2 +HCl method as
you describe is the regeneration of the solution. H2O2 is
chemical regeneration and is instant, while atmospheric
oxygen regeneration is slow (can take from 1/2 hour to many
hours). In both cases CuCl2 is doing the etching and CuCl is
the byproduct, which oxidizing back to CuCl2 in regeneration.
2CuCl + O + 2HCl -> 2CuCl2 + H2O
(note that HCl is consumed during the reaction)
Is too cumbersome to use CuCl2 etching in small trays. You
need a dedicated etching tank, similar to what is described
at
http://users.rcn.com/rexa/Projects/CuCl_ech.htmlreasons for a tank;
∗ less potential for spillage
∗ no setup time, always ready to go.
∗ Large solution volume relative to copper mass. This is
very important for effective etching using this technique.
(See previous posts.)
No heating if you are satisfied at 35 um copper etch in < 20
minutes at 20°C. Etch 35 um copper in 30 minutes at 13°C.
I'm still learning about this etchant and how to use it. I
haven't yet worked out the "minimum equipment" needed to
analyze and maintain the solution. It could be nothing more
than a eye dropper and some supermarket chemicals.
One day I might create a web page on air regenerated CuCl2
etching for the hobbiest.
Adam.
stefan_trethan wrote:
> First Hi to all, as you may guess I'm new to this Group. If I don't regard any rules or common behavoir suggestions please point it out.
>
> To the question:
> I have read of the CuCl process here for the first time.
> I used Fe3Cl (awful) and now HCl and H2O2 for a while. I'm satisfied with H2O2 but it must be filled up every time etching.
>
> There was a discussion about H2O2 before, mentioning half the HCl volume of H2O2 would be needed but i don't agree. Only a few drops are needed each time to get the etchant to bright green from dark brown (as with CuCl. The etchant can be filled in a bottle after use (punched cap, H2O2 gases) and reused for ever. I etch in several small plastic containers (different pcb sizes), to use as little etchant as possible (to need less H2O2). only putting it in, etchant on top works fine (small bubbles from H2O2). It's ready in a time from 10 seconds up to a few minutes (H2O2 concentration decides).
>
> I figured this out exactly because I don't know if anyone has used it before and i want ask you for comparing it to the CuCl method.
>
>
> Please specify the differences of CuCl, especially the advantages.
> This would be a great help to decide if a change would be a good thing.
>
>
> What i figured out 'till now:
>
> Disadvantages:
>
> needs Bubbler
> needs long term regeneration
> needs complicated analysis for concentration determination
> needs big tank where a relatively big amount is stored
> (needs heating to work fast)
>
> Advantage:
> Needs NO ingredients to be replaced / refilled????? (I know this is wrong but what has to be refilled, HCl???)
>
>
> Thank you for any explanation.
>
> Also i'm much interested which of the described analysis methods is actually needed (density, ph, ..) aer they ALL needed or only ONE?, I'm not a chemist, but i believe i can learn everything.
>
> It would be very nice if one can give a quick review, I'm a bit buffled by the much different posts.
>
> Point for point short quick guide would be nice with simplest way to do it.
>
>
> kind regards
>
> Stefan Trethan
>
> Austria
>
>
>
>
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