Yesterday I just bought a couple of pounds of ferric nitrate at
Bryant Labs in Berkeley for $22.95 each pound. I live in the area so
I didn’t have to pay the hazmat shipping fee of $25 which someone out
of the area would have to pay. I don’t know of another supplier
although I’m sure they’re out there. Bryant Labs’ contact info is
(510) 526-3141, 1101 Fifth St., Berkeley, California.
Using an earlier jar of ferric nitrate I’d bought there, I found
that my silver etched quite quickly – several batches etched quickly
for up to a total of 5 hours. After that, just as when you etch
brass/copper with ferric chloride, the etching slowed dramatically.
I left the very last batch of earrings I did in the solution for a
couple of days, total. The ferric nitrate still etched, but ever so
slowly. (I have a setup with an aquarium pump duct-taped to the
container to agitate the solution, so I was doing that right). It
just seems like the stuff slows down after 5 hours use.
I’m wondering whether to add new ferric chloride to the spent
solution (acid to water, like you oughter) or just take the old
solution to the hazardous waste disposal site and start afresh. Does
anybody recommend one way or the other? The guy at Bryant Labs (who
clearly had a degree in chemistry) was very helpful and started
talking to me about adding potassium to the spent, silver nitrate
laden solution, and precipitating everything out (presumably this
renews the original ferric nitrate), but sorry to say he lost me