Etching sterling with ferric nitrate

Jewelry Discussion
21

Ian,

You can also just duct tape the back of the piece, use some double
sided tape and tape the polystyrene. It floats very nicely. Mark the
time on the top so you can remember how long your piece is etching.
This creates a nice handle for picking up your metal.

-kj

Karen Christians
M E T A L W E R X
50 Guinan St.
Waltham, MA 02451
Ph. 781/891-3854 Fax 3857
http://www.metalwerx.com/
Jewelry/Metalarts School & Cooperative Studio

22 
I gotta say, it isn't clear to me why it might be better to go
through all that than to etch with nitric acid in 10-15 minutes.
Is there an advantage to the ferric, in your opinion?

I’ve done a fair bit of etching with nitric acid on previous
projects, and it is waaay faster, but I found the ferric nitrate a
much gentler process - there was almost NO undercutting, which was
the major headache I encountered with nitric acid. Case in point:
the last time I used nitric acid, I was etching the continents on a
pair of hemispheres for cufflinks. I needed a deep etch, since I
would be making domes from the etched discs, so I etched them for
about 30 minutes. When I was done, the Great Lakes had grown to the
size of an inland sea, and Indonesia and Japan were reduced to
skinny little ridges.

Also, the ferric nitrate worked well with PnP, which reportedly
doesn’t stand up to nitric acid. The PnP allowed for a much faster
and more accurate design transfer, even if it did need to be
repainted after a while. A disadvantage: the ferric nitrate was
totally kaput after about 30 - 40 hours of continuous use, while the
nitric acid I have is about ten years old and still going strong!

    did it still etch OK through the residue you described, or did
you have to keep cleaning that off?

I cleaned off the residue at least once an hour, if not more
frequently. I think it will slow or even prevent the etching process
if left alone.

         I use a used magnetic stirrer (bought cheap on eBay) with
copper and ferric chloride; it speeds the etch considerably,
though on large pieces, you may see uneven depth from the
"currents" of the spinning liquid.

This is a GREAT idea! It crossed my mind while I was fiddling with
the aquarium pump (I had used stir bars often in microbiology labs),
but I dismissed it because I thought the stir plate would be too
expensive. Time to visit eBay!

I forgot to mention in my earlier post that, stir bar or no stir
bar, I also got ripply patterns in the etched areas. They seemed to
radiate outward from the center of the piece or from the edges of
design lines. Other posts or articles I read about etching indicated
that this might be caused by the high strength of the etchant.
Actually, I quite liked the patterns the ripples formed, which added
a nice organic touch to some pieces and provided a good “tooth” for
the Durenamel on others.

Cheers,

Jessee Smith
www.silverspotstudio.com
enjoying a cool night near Lecanto, FL

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23 
Actually, I quite liked the patterns the ripples formed, which
added a nice organic touch to some pieces and provided a good
"tooth" for the Durenamel on others.

I have found that this ripply pattern also looks quite lovely under
transparent enamels. I like having some sort of texture on the
metal as it adds more depth in my opinion.

Vicki Embrey

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