My ferric chloride etchant was obviously exhausted, when I was etching a
couple of small boards this afternoon, so I sloshed in some H2O2, reasoning
that it would oxidise any cuprous chloride to cupric chloride - an etchant
in its own right. There was a lot of fizzing and the board finished etching
in seconds. I had previously added some HCl to prevent sludge build-up, so
the excess chloride and oxygen ions might be doing all the work.
Leon
--
Leon Heller, G1HSM
leon_heller@...http://www.geocities.com/leon_heller