have seen the situation happen several times ......as you have suggested .....
clean out the bag ........ but another condition also can lead to this
symptom. when high aspect ratio work is being produced for an extended period
at low current density. I have witnessed over the years that when low current
density is applied for distribution of the copper plate on the surface, the
actual anode current density when drops below 10asf - will cause a thick
cupric chloride film to form. eventually the film being so thick will fall off
the anode and into the bag - sludging as some people call it - block the bag -
and voila!!! FORMATION of copper sulfate - as you have indicated. think
someone should actually take a look at the number of anodes are in the tank -
lot of other reasons why this occurs - but the one u had mentioned - is  a
primary reason - with several conditions occurring as to why it happens.


Richard Fudalewski

Atotech Canada Ltd

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