Homebrew PCBs

"this looks a bit dark, I'll add some H202"
   "this is taking a bit long, I'll add some HCl"

In short, doesn't really matter.

H202: The darkness of the colour of the solution tells you the 
concentration, you want it light green.  Add H202 to re-green.

Acid: To quote from Seychell,   "In other words don't worry about high 
acids."  The acid content has an effect on the etch time, more acid, 
faster etch.  But more acid means more fuming.

NB: The original Seychell document that massmind has copied has images 
of the color of different concentrations, unfortunately Adam's original 
URL is blocked due to malware on at least Chrome, I've made a PDF copy 
of it for those who can not easily view the original, page 6 of this PDF 
has the concentration comparison image - 
http://sparks.gogo.co.nz/seychell.pdf


On 13/05/14 14:38, 'Boman33' boman33@... [Homebrew_PCBs] wrote:
>
> With the visual/feel method, when the reaction slows down, how do I 
> know if I need to add more HCl or H2O2?
>
> .
>
>