Vibration to speed etching

Hi, folks-- A few days ago there was a post that suggested taping an
aquarium pump to your etching container to agitate it. This swounds
like a good idea to me–plus, if you arrange your piece to be etched
on edge so it can’t trap bubbles, the air from the pump can be
channelled into the mordant to circulate it. I would just like to warn
against a “brilliant” idea I had. I taped the etching container onto a
little stand that is intended to vibrate casting investment in the
absence of a vacuum. The first time, it seemed to work great. The
second time, however, I noticed that it had a rheostat to controll the
vibration. More is better, right? I turned it up–and the mordant
suddenly formed the most beautiful little fountain in the middle,
shooting up maybe two inches, then arching out in all directions, well
past the edge of the container. The switch was under the shower, and
the plug was behind it. I could not immediately turn it off. I found
some long enough gloves to reach through the spray and shut it down,
but it was quite a mess, acid everywhere.

Maybe no one else would be so boneheaded, but you never know,
so…anyway, now it makes a good story. Best of luck to all!
–Noel