On Tue, 05 Apr 2005 08:04:22 -0700, in |õ Ted Frater wrote:

Are you sure you want ferric nitrate?
Because its ferric chloride thats used in the printed circuit board
industry to selectively remove the copper to make the circuit tracks.

If Charlie is wishing to etch a copper based alloy, then you're correct Ted, ferric
chloride is the right stuff. But for etching silver, and a number of other metals, then
ferric nitrate is the one. In both cases, these are safer to use salts of respectively,
hydrochloric, and nitric acids. HCl doesn't work well to etch silver, and neither will
it's salts. The salts, in addition to being safer to use (primarily in that they don't
produce the same level of nasty fumes in their concentrated forms), also offer a more
uniform etch with generally fewer problems with undercutting and lifting of resists.

Peter