Homebrew PCBs

Your gut feeling is right, blue color indicates a lack of HCl.

Even if you add H2O2 it will just not do anything. There may also be a  
blue stuff deposited on the copper.

Add HCl and all will be well again. You probably also need to regenerate  
after that.


You may want to look into measuring HCl molarity, look through the CuCl  
links section for the eyedropper method.

ST

On Tue, 02 May 2006 11:04:19 +0200, Bill Westfield <westfw@...>  
wrote:

> Does anyone have any ideas why my regenerated CuCl etchant would
>
> be a blue-green color rather than the bright green I see on assorted
>
> web pages?  Etch speed sucks too   Perhaps I areated away all the
>
> HCl?  Are there impurities that would cause blue rather than green?
>
> (THis is home-made etchant from HCl, H2O2, and assorted bits of scrap
>
> copper; wire, pipe, etc...)
>
>
> Thanks
>
> Bill W
>