Homebrew PCBs

On Mon, 7 Apr 2014 00:32:24 -0400, you wrote:

>I have a question about starting CuCl etching.  I have done the
>obvious googling and reading, but have been at a bit of a loss for
>this one.
>
>I happen to have some CuO on-hand, so I have the option of going
>directly to CuCl rather than go the HCl + H2O2 route or HCl + H2O2 +
>copper chunks.

I've never quite understood the direct route, that is, going from H2O2
and HCl by adding copper to get the etchant, I know why it works, but
the logic escapes me.  

I just start out with the H2O2 and HCl and use it to etch boards, and
end up with CuCl etchant when it gets there.

>
>I know that 35% H2O2 + HCl works quite well, but there seem to be
>mixed reports about etching with 3% H2O2 + HCl.
>
>Since I only have 3% H2O2 on hand would it be better to start with
>that, and the let the CuCl form naturally, or should I mix up a batch
>of CuCl and start etching with that?

I'd do the H2O2 at 3% which worked fine for me.  The mixture I used
was 4 parts H2O2 to 1 part HCl, and that etched boards quite well.

>
>I am planning on using a bubbler to convert CuCl to CuCl2 over the long term.

I used a bubbler as well, worked well for me.

Harvey

>
>Many thanks in advance.
>
>-p.