[sdiy] Etching PCBs with non-toxic chemicals

[Paul Perry]

Well, after the copper is all deposited on the scrap, you could add washing 
soda or
sodium bicarbonate (possibly easier to obtain) to precipitate the aluminium 
as
insoluble aluminium hydroxide. All you are left with then, is sodium 
chloride - common table salt.

An alternative is to evaporate the PCB solution waste to dryness & dispose 
of with the
REALLY poisonous waste you have, like old medicines and mercury batteries.
Wherever you do that.

paul perry Melbourne Australia

----- Original Message ----- 
From: "Matthew Smith" > Quoth Paul Perry at 07/03/11 08:30...
>> You can add excess scrap aluminium to give non-toxic aluminium chloride
>> and metallic copper. if my memory of chem classes 50 years ago is right..
>
> Although I wouldn't want to pour it on my plants! (Excessive
> concentration of salts.)
>
> -- 
> Matthew Smith
>