Greetings.

I'm new to this forum.  Since I'm not an EE and only last week
purchased a Picstart programmer, I don't even know enough to ask
relevant questions yet.  In time....

Being a chemist by profession, I found the recent thread on PCB
chemistry quite interesting.  Electrolytic rejuvenation of FeCl3
etchant is something that I've been meaning to try for ages.
Pleased to hear that it actually works.

It should be pointed out that there are two processes that must
occur: 1) removal of copper ion from solution; this happens by
reduction to copper metal at the cathode; 2) more importantly,
oxidation at the anode of Fe+2 back to Fe+3.  If the latter does
not occur, the etching power of the solution will not be
restored.

Which leads to the following point: what should the anode be made
of?  One gent mentioned using steel. With all due respects, I'm
surprised that that works, unless the steel is the "right" kind
of stainless.  The problem is this: oxidation occurs at the
anode, and if the anode is made of an easily oxidized metal, the
anode itself will oxidize and erode.  (For the purposes of this
argument, iron and many types of steel classify as "easily
oxidized.")  Because the current is serving to oxidize the
material of the anode, little or no rejuvenation of the etchant
will occur.

Anyway, I would be interested in hearing any other stories of
success in this process, especially what people have used for
anodes.

Steve Turner

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