Homebrew PCBs

You don't need to add more copper. The dark green is cuprous chloride. 
Add more H2O2 or bubble air through it to convert it to cupric chloride. 
It will turn a lighter green as it converts. You may need to add acid if 
it doesn't etch very well. IME bubbling air through it takes quite a 
long time. You need fine air bubbles like you get from an air stone but 
air stones disintegrate in the acid.

Les

Howard wrote:
> Hi
> I have been doing etching with HCI (Spirits of salt 32%) 
> and H202 (6%) in a mix of 1 part HCI to 1 part H202, in small
> amounts (.5ltr), after etching i then put the acid into a 3ltr
> bottle, now the bottle is full of medium to dark green stuff!
>
> So now i would like to make use of it to make CuCI.
> Now i think that i need to add some copper to the mix and pump
> some air in.
>
> I have a Mega-UK type of tank with a built in air pump and heater
> it holds about 5ltrs. Could i just put the 3ltrs of used mix into 
> the tank, add some copper(how much?) and turn on the air(how long for?)
>
> When will i know when it is converted to CuCI ?
>
> Hope that someone can put me right on this
>
> Regards
> Howard
>