Homebrew PCBs

>
> Can I ask why are you trying to produce hydrogen gas at all ?
> Are you saying that no visible signs of copper are plated without also
> producing hydrogen gas at the cathode ? If this is the case then you must
> have very little copper dissolved in the solution, such it would almost
> look very pale clear green.
>

no, i get copper with no hydrogen too.
I aim for a area ratio that starts to produce hydrogen and chlorine at the 
same time,
and then use current slightly below that point.
It is better if i get hydrogen before chlorine because that means the 
copper area
is the absolute minimum. if i get clorine earlier then the copper could 
still be made
smaller.


> that's correct. When metal and gas co-deposit you get metal sponge.

correct, with lower current (no gas) i get no sponge, but a rough solid.
>
>>
>> I have also another question about chlorine, what are those tablets made
>> of for the swimming pool?
>
> calcium hypochlorite. This may regenerate CuCl2 etchant but I'm not sure
> the effect of byproduct, calcium chloride. It may not make a truly 
> reusable
> etchant. commercially, they sometimes use sodium chlorate, which is 
> similar
> except it is a more powerful oxidant, (more economical), and the 
> byproduct
> is sodium chloride.


i only ask because i have some leftover...
I might try it, but also might not. I guess it would not exactly decrease
clorine gas production.....


Yesterday i let it run for several hours with some 200mA and at then end i 
got visible regeneration.
I didn't want to run it overnight without supervision so i turned it off 
and pulled ou the copper.
now i will go and switch it on again i think.

The lid for the vertical tank seems to be set now, but i have still some 
work to do before i can
activate it.
It will hold 1 liter of etchant, and accept boards up to 35cm x 20cm which 
is more than i need.
It is also about the size i can make a TT (A4).
I'm stuck right now with creating the lid, it got more complicated since i 
aimed for electrolytic
regeneration. Right now i think i will seperate the lid in 3 sections, the 
middle conaining
the pcb clamp and the outer 2 containing the electrolysis electrodes. This 
way i can input/output
boards without disturbing electrolysis and i can also completely remove 
the electrodes if i should
once need the whole 35cm length. I will most likely make the copper 
electrode holding lid twice,
one holding a wire, the other blank, because obviously the copper needs to 
b taken out
if there is no current present.


I'll write again when there are new results or questions.


I would have one other question now - do you think the etchant penetrates 
the welding rods?
I connected them by drilling a hole and inserting a wire. then i sealed it 
with silicone.
If the etchant seeps through this is no good of course.

ST