What is the concentration of copper chloride? How much free acid is there (approximately)? Are you generating the copper chloride in situ using hydrogen peroxide and HCl?
With fresh etchant and under reasonable conditions, it is hard to imagine that the etchant became exhausted with just one board. I suspect it is something else.
Can you post a picture of your etchant that stopped working against a white background. A drop or two on clear glass with white background would be even more informative. Can you show the board?
Is your resist toner or a photosensitive resist? Positive or negative acting? If your developer is alkaline (e.g., sodium hydroxide, sodium carbonate, etc.), then your partially etched boards should be stable once washed. No need for darkness, but I would't lay them in bright sunlight.
As for regenerating the etchant, the easiest way is to just bubble air through it. Hydrogen peroxide will do the same a bit quicker, but you may want to use a more concentrated, such as 30% or more as mentioned before.
John
Hi There
Thanks for your help. Im sorry if i cant answear all your questions correctly as i am new to this but here goes;
I started with
600 ml hydrochloric acid (28%)
400 ml hydrocgen peroxide (9%)
I am using posotive photosensitised resist. The developer is sodium hydroxide 10grams in 1L. The board developed
niclye showing sharp dark lines where they should be.
I have done some test boards. Though i did not get the "fizz" i was expecting after wathing videos on you tube. I did get some fizz but not as much as i was expecting.
I cannot get any pictures at the moment. The etchant is green though not hugley dark green.
I think i have made a few mistakes that i can see.
Firstly I poured all of the solution I made into my etching tray. i think I may have been better just using what I needed.
Secondly i made the solution using all of the peroxide I had in stock. this has left me little room for regeneration.
Thirdly I did some test strips to get comfortable witht the process.. probably used 2 160x200mm cards. Maybe this has exhausted the ethcant.
How long does it take to regenerate using air?
I have seen ething tanks with air diffusers in, i think making one of those will be my next task.
Thanks again
your help is appreciated.