Etching non-flat surfaces

I have some rings that I am designing and would like to etch them.
I’ve heard that the best way to use PNP or other etching techniques
is to etch a flat piece. However, if I etch the band before I shape
it and solder it, I’m going to have troubles lining up the edges and
matching the etched patterns. Has anyone had success using PNP paper
on non-flat surfaces?

Don’t even try it. PNP if not that flexable, nor does it stretch
around curves. You have a much more complicated problem; what with
masking the inside, seams of overlaping mask, etc. It would be a
nightmare. Careful planning should net you two ends that match. At
most a touch with a bur to clean up any solder is all that should be
necessary. There are charts available that will give you the exact
length of the band for it size and thickness. Getting the ends to
match should be easy. Bill

Reactive Metals Studio, Inc.
PO Box 890 * 600 First North St. * Clarkdale, AZ 86324
Ph-928/634-3434 * Ph-800/876-3434 * Fax-928/634-6734
@Michele_Deborah_Bill

Catherine, I’ve etched small copper bowls, ash trays, etc (round and
square). I’ve never tried to etch rings, although if you used a
forgiving pattern with a bit of detail, you might be able to fudge
enough to make it work (or you can be really, really careful about
where you place the PnP!) When I’ve etched small, steep round bowls,
my usual method of suspending the piece upside-down in a bath of
ferric chloride won’t work. However, I keep filling the bowl with
ferric right to the brim, letting it etch, then refilling it with
fresh, and so on. The etched patterns I get are subtle and soft, but
they still look nice. Another thing to do would be to etch the piece
(changing the liquid in the bowl every 20 minutes or so) in hot,
direct sunlight. That speeds up the etching process like crazy.