I haven't done a lot of etching as I may have mentioned and
haven't any experience with the toner method. It seems a little
indirect for my tastes but I will be watching for your results!
Just a thought . . . Has anybody tried using toner directly,
instead of transfering it from a photocopy?
Sprinkle powdered toner (available at Staples & Office Depot)
over the entire piece to be etched. Use a piece of fine mesh
screen to get an even coating. Next, draw your design into the
toner coating. You could use just about anything to do this --
the end of a tooth-pick, small paint brushes, or perhaps pencil
erasers carved into different shapes.
When you are satisfied with the design, pop the piece into a
toaster oven (or fairly cool kiln -- whatever) for a minute or
so to set the toner. (It can't take much heat to melt the stuff,
or else laser printers and copiers would set fire to the paper.)
Finally, etch the piece as normal, and then buff off the toner.
Alternatively, you could coat the piece in toner and bake it on,
and then use a hand piece with fine tipped polishing points to
clean off the parts you want to etch.
I've never done etching, so I have no idea whether this would
work, but it seems logical enough. . .