Homebrew PCBs

On Tue, 1 Mar 2005 21:04:21 -0800 (PST), Naveed Alam  
<naveedguy2@...> wrote:

> I bought a copper board. The shop-keeper also gave
> CuCl but that is in the solid form. Can anyone tell me
> about the proportions of water and this solid used to
> prepare solution for etching. Can I also use some
> other chemical to improve the etching process or make
> it faster. It's black in colour. Is it OK?


If it is really CuCl you can use it, i think there is some text in the  
links section about this black powder and how to prepare it.
My gut feeling is a flame should turn blue (maybe green) if you put a  
small amount of powder in.

In any case, you need HCl (Hydrochloric acid), which provides the Cl for  
forming more CuCl from the copper on the PCB.


Also, you need either a air bubbler, or H2O2 to regenerate the etchant  
(The added oxygen makes the Cl free from the HCl by forming water i  
think). I suggest a bubbler in any case because it is cheap (10eur  
aquarium airpump) and it speeds up etching dramatically. I prefer H2O2 for  
regenerating, because it isn't expensive and "instant" rather than tedious  
bubbling.

ST