Originally Posted by Mr Gazza

Thank you for that Nick.
Thank goodness I will be able to sleep soundly tonight, assured that it's not my Oberon slave that's blacking my fluid!

So what are we going to do about the master chaps? As far as I know it's not possible to anodise inside a bore for the same reason that you can't electroplate inside a bore or tube. There is no electrical potential, the electrolyte is only exposed to the polarity of the tube or bore wall. Or am I wrong?

First thoughts are to line the master bore with something. A stainless sleeve perhaps?.. Shouldn't be beyond the wit of man, if a little fiddly!