I have been teaching galvanic etching for several years now and am
having great success in my classrooms. We use a copper sulfate bath
for etching copper and copper alloys and copper nitrate for etching
silver. Other than having to occasionally strain the sludge from the
bottom of the container (I use a coffee filter in a funnel) and
rarely adding some copper sulfate or nitrate (when needed) I can use
the same bath for years and countless etchings.
I also find batteries expensive and find them environmentally a
problem, so I have use a small 30V 5A rectifier. These are available
on ebay for about $65. For the attachment to the anode, you can tape
copper wire on to the back, solder it on or drill holes in the
corners of your work and make hooks on the ends of the wire to hang
the piece. We usually use a full sheet of copper for the cathode and
just bend over one end to hang on to the edge of the container.
The etchings my students are able to get are amazing. Very clean and
can be very deep. We use PnP, vinyl, paint pens, stickers, paint,
fingernail polish, and stamps as resists. Some hold up better than
others, but we have gotten all to work.
I have attached the checklist I laminate and use at each station in
the classroom – just to make sure everything is is taken care of
properly! This might help with some of the issues some of you are
having with galvanic etching.