On 28 Oct 2011 01:42:54 GMT, "DoN. Nichols"
wrote:

On 2011-10-27, wrote:
http://www.flickr.com/photos/2768312...in/photostream

Previously when I saw pits like these I thought it was caused by pin
holes in the resist. There was some discussion about its here. I
firmly believed that it was the hydrogen bubbles cavitating causing
this. However, in this case there is *no* resist!

Are those truly pits, or are they projections? I could imagine
air bubbles (or hydrogen) forming on the surface which would prevent as
much access from the etchant.

Either tapping the edge every so often, or applying ultrasonics
from a cleaner might break them up fairly quickly.


They are pits and quite deep at that. The main reason I have the
cathode on top now is to allow for the hydrogen to escape without
coming into contact with the work-piece.

I am going to try a few things tomorrow and see what pans out.

Michael Koblic,
Campbell River, BC