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Mordants


#1

I have a problem with it too. Ferric chloride works on copper. Ferric
nitrate works on silver. I bought some ferric chloride at Radio Shack
and tried it out. The bottle says: Contents: Ferric Chloride, so I
assumed it is undiluted ferric chloride. I dropped a very little
piece - appr. a half square inch of 18 ga. - copper in what I
consider to be a generous amount of the ferric chloride. In the
beginning, the copper started to bleed somewhat - it was very minimal

  • but then the reaction stopped. This piece has been sitting in
    ferric chloride for 2 days by now and nothing happens. The info on
    the bottle says that it takes appr. 20 minutes to etch copper
    connections away - it’s for computer people. Warming doesn’t help
    either. What do you think is wrong? Thanks and best, Will

#2

I had the same problem with feric chloride. My copper sat in it
for several days and nothing happened—it just changed color. I
then got so me ferric chloride from another source—used to supply
the computer indust ry with theirs, and it worked fine. It may be
that the stuff from Radio Sha ck is old. Does Ferric Chloride have a
shelf life:. Alma


#3

Will, You say your copper has been “sitting” for two days. What is
it “sitting” on? If your piece is lying on the bottom, you will
never get a decent etch. There are two things you need for a good
etch.

  1. your piece needs to float image side down

  2. the acid needs to agitate

Both can be solved quite easily. Take some double sided sticky tape
and tape the back of the piece to a piece of styrofoam. This will
act as a lovely little pontoon.

Get a cheap aquarium pump, and strap that puppy to the outside of
your plastic container. Plug it in and let it vibrate away. Now
the acid is gently agitating, taking away the little metal bits that
are etched by the copper.

I guarantee this will work.

-k Karen Christians M E T A L W E R X 10 Walnut St., Woburn MA 01801 Ph.
781 937 3532, Fx. 781 937 3955 http://www.metalwerx.com/
Jewelry/Metalarts School & Cooperative Studio


#4

When I used the radio shack etching solution on copper it worked
well. For the best results suspend the piece and if you can aerate
it with a fish tank pump.


#5

Morning Will, I have a few thoughts about the ferric chloride you’re
using. It might be that you’ve exhausted the solution and there is
no more ferric chloride left to react with the copper. This being
the case, you’ll need to change the solution. Did you know that
etching with ferric chloride causes sedimentation? The copper does
not go into solution as it would with acid but precipitates out. If
your piece is lying face up, the sediment stays on your piece and
prevents access of the mordant to the copper surface to be etched.
To prevent this, you can either remove the piece occasionally and
rinse it in water, agitate the solution on a regular basis or
install a mechanical agaitor (such as an aerator for a fish tank).
Lastly, there has been some research posted on the web about etching
with ferric chloride with a citric acid additive. The latter is a
food-grade acid and can be purchased in health-food stores. The
revised process is called the Edinburgh Etch method. I apologise
for not posting the site but my notes are at home… I hope this
helps Eileen