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Etching


#1

Hi folks,

I followed the thread on etching that appeared here a little
while ago and printed out the instructions that “Fishbre” was
kind enough to post. Shortly thereafter a customer came in with
a custom job that seemed ideally suited to this technique, so I
thought I’d give it a try.

I used a standard DC transformer (usually used for the operation
of model trains) and found that this technique seems to work well
for etching lines, but not for larger areas. The background of
my test piece came out looking like a silver version of Van
Gogh’s “Starry Night” with blobs and whorls all over the place.
After grinding down the highest spots with the flex shaft and
darkening the area with Silver Black, the piece looked
presentable, but not up to my expectations.

The other interesting things I found were that this process eats
alligator clips at a very fast rate. I ended up having to coat
them with resist and tried to keep them above the water as much
as possible. If I use this method again I will allow a much
longer tab for the clip. This process was confusing to me at
first as it seemed to be plating rather than etching the piece,
but I found that the build up was easily removed and that the
underlying silver had indeed been etched.

Anybody else tried this yet? I’d appreciate any tips on getting
this to work better. I do like the fact that I did not have to
purchase any acid or end up with the problems of disposal of
same.

Thanks to everyone on this forum for sharing helpful

Elaine (MoonStones)


#2

I’ve never tried large open areas . . . but, I also had the same
good results with small lines. I have to say, also, that I
wasn’t very impressed with the “acid etching” we did in class. I
expected to see very defined lines, but what we got (with nasty
acid . . . and now that same acid is over 4 years old, and still
at the ART center where I learned the regular method, and in a
glass gallon jug! I dread the thought of some “unknowing” soul
dropping that glass jug!) was very undefined! I can do better
using an electric etching thingie from Sears!!! (It’s shaped
like a dremmel tool, but has a carbon point, there are various
settings for vibration - not easy to control) but it will ETCH.

Sorry, I forgot to mention that the salt/water etching method
does eat alligator clips . . It will desolve those suckers in
no time! I was considering just soldering the copper wire (from
the battery ) to the piece I wanted etched, but haven’t had time
to try that! (I am not sure whether copper is eaten away at the
same rate as alligator clips!, which are not copper.)

I haven’t had a lot of time to try this method . . . too busy
doing other things . . .

 The other interesting things I found were that this process
eats alligator clips at a very fast rate.  I ended up having to
coat them with resist and tried to keep them above the water as
much as possible.  If I use this method again I will allow a
much longer tab for the clip.  This process was confusing to me
at first as it seemed to be plating rather than etching the
piece, but I found that the build up was easily removed and
that the underlying silver had indeed been etched.

Are you referring to the “black water” which appears? Yes, there
is a lot of that, but most of it will wash off, or will be
removed after the piece is dropped into pickle.

    Anybody else tried this yet?  I'd appreciate any tips on
getting this to work better.  I do like the fact that I did not
have to purchase any acid or end up with the problems of
disposal of same.

I’m happy to hear that someone else had the same results as I
did, I’m sure if we work on it, we can perfect this method!!! ; )


#3
 Are you referring to the "black water" which appears?  Yes,
there is a lot of that, but most of it will wash off, or will
be removed after the piece is dropped into pickle.  

I’m not sure what you meant by the above. The water certainly
did turn some unlovely shades of black, rust, and greenish scum,
however, I was referring to a solid deposit on the exposed
silver. It has to be some metallic compound, but I’m not sure
exactly what metals make up the alligator clips or the metal pan
used in this process and wouldn’t like to take the chance of
contaminating the pickle. I found that the stuff would peel of
pretty easily in most areas once I managed to lift an edge with
my soldering pick.

Thanks for sharing the

Elaine (MoonStones)


#4
  I'm not sure what you meant by the above.  The water
certainly did turn some unlovely shades of black, rust, and
greenish scum, however, I was referring to a solid deposit on
the exposed silver.  It has to be some metallic compound, but
I'm not sure exactly what metals make up the alligator clips or
the metal pan used in this process and wouldn't like to take
the chance of contaminating the pickle.  I found that the stuff
would peel of pretty easily in most areas once I managed to
lift an edge with my soldering pick. 

Hmmm, I did not encounter this, Yes, I was referring to the
color of the water (black water). . . I wonder . . .would
soldering the copper wire directly to the piece being etched
solve any of the problem of any metalic compound buildup??? I
don’t know . . . I’ve never tried doing that.


#5
  I found that the stuff would peel of pretty easily in most
areas once I managed to lift an edge with my soldering pick.

hi elaine,

are you sure your silver was new metal? do you pour your own
ingots and make your own sheet? are you observing the 50/50 rule
of new and old metal?

it sounds to me, and i’m just guessing that your metal wasn’t
melted in a non oxidising way or the metal wasn’t clean prior to
melting, i.e. melting benchsweeps without observing proper
precautions to ensure reasonably clean metal.

i’ve never personally etched anything in my life, but have done
a fair amount of refining. one of the methods i’ve used is the
simplicity system by shore (not reccomended by me). when one
would melt bench sweeps into an ingot without using highly toxic
ammonia chloride for flux, the ingot wouldn’t dissolve at all.
the result would be be a flakey ingot, like the flakes you’ve
described.hth best regards,

geo fox


#6
   This process was confusing to me at first as it seemed to
be plating rather than etching the piece, but I found that the
build up was easily removed and that the underlying silver had
indeed been etched. 

In this case, you need to reverse the leads so the current flows
in the opposite direction.

Penny


#7

Hi George:

In reply to your posting, the silver I’m using is sterling sheet
which I purchased from Rio. I’ve never had any problem with
"flaking", etc., except when I tried the saltwater/electric
current method of etching, so I still think that the deposit on
the silver was due to the process. The dissolved alligator clips
had to go somewhere and I suspect the buildup on my silver was
partly composed of whatever metal they were made of.

Elaine (MoonStones)


#8
   This process was confusing to me at first as it seemed to
be plating rather than etching the piece, but I found that the
build up was easily removed and that the underlying silver had
indeed been etched. 
   In this case, you need to reverse the leads so the current
flows in the opposite direction. Penny 

G’day - here I go again, jumping in! When plating or
de-plating electrically (etching, stripping), remember that the
mobile metal is always attracted to the NEGATIVE pole or
terminal. So, think of it as the positive terminal positively
pushing the metal ions OUT. Cheers,

        /\
       / /    John Burgess, 
      / /
     / //\    @John_Burgess2
    / / \ \
   / (___) \
  (_________)

#9
   In reply to your posting, the silver I'm using is sterling
sheet which I purchased from Rio.  I've never had any problem
with "flaking", etc., except when I tried the
saltwater/electric current method of etching, so I still think
that the deposit on the silver was due to the process.  The
dissolved alligator clips had to go somewhere and I suspect the
buildup on my silver was partly composed of whatever metal they
were made of.  

hi elaine,

thanks for replying, i love to know when i’m right or wrong in
my guesses. i agree that the mtal itself is not the problem.

if metal is being deposited on your workpiece, the leads are
reversed as some one pointed out on a earlier post. i’m not an
electrical engineer, but i think d.c. current flows from
positive to negative. or from anode to cathode. the workpiece
for etching would be the anode. one could immerse a copper
cathode in the electrolyte solution to plate out the removed
metal onto the cathode. again, i’ve never etched anything and am
not completely familiar with the method you are using. i have
done a lot of plating, or at least enough to know i dislike
doing it intensely.

best regards,

geo fox


#10
  The dissolved alligator clips had to go somewhere and I
suspect the buildup on my silver was partly composed of
whatever metal they were made of.  

Greetings,

The alligator clips (for some applications unless made of
platinum, yeow!) are NEVER intended to be immersed in etching
solution! If the alligator clips ARE immersed you are PLATING
with the steel and chromium that make up most alligator clips!!

Some simple solutions include: Leave a tab of metal that will be
ABOVE the etching solution and then you can attach there &
alligator clip the nite away ABOVE the solution (watch for
splashes on the a-clips).

Platinum (in general) is very non-reactive and you can make a
simple tension clip to hold your work in the solution and then
alligator clip to the platinum. You will get a very small amount
of platinum plating. If you use very strong acid and current then
you MIGHT move more of those tight, expensive platinum atoms to
your work piece.

Here’s hoping this is adding to (plating) rather that detracting
from (etching) the Orchid awesome psyche or is it
libido…NEVERMIND…

Wm.

             Mystical Grits
         Wm. Augustus Mason

Metaphysical Jewelry, Crystals & Gems,
url: http://www.concentric.net/~lightone/
Easley, South Carolina
Original Spiritual Space Jazz Heart Music
Furniture Design
Food Design & Creation
Ideas, Fantasies, Visions, Conscious Creations
Feel Good, Be Happy, Enjoy LIFE!


#11

Hi again, and thanks to everyone who took the time to add to
this thread. My apologies for obviously not being clear enough
in my postings.

I thought at first that I might have gotten the wires reversed
(especially since I was using a transformer for model trains —
the positive and negative poles are determined by the direction
switch). I double checked the instructions and the polarity of
the terminals before I tried again.

The important point is that this process does work although it’s
better for etching lines than for removing larger areas. Once I
removed the mystery build-up I found that some silver had been
removed from the areas left exposed. My designs show up pretty
well and the only remaining problem is that the etching was very
uneven over larger areas and I had to use the flex shaft to even
out the lumps and bumps in these places. I only mentioned this
"plating" effect so that other people who try this won’t be as
confused as I was before I discovered that it was easily removed
and etching had taken place underneath.

Thanks again!

Elaine (MoonStones)


#12
   Once I removed the mystery build-up I found that some silver
had been removed from the areas left exposed.

If you’re etching silver in a salt (Chloride of any sort)
solution, then as the silver dissolves, it form silver chloride.
Silver chloride is completely insoluable in water, and will
immediately form a precipitate. I’d guess that your mystery
layer is silver chloride. Unless the etching process is causing
considerable bubbling action to physically carry the chloride
away, it will stay right there on the surface. Trying to etch
silver with hydrochloric acid by itself, for example, doesn’t
work because the silver forms a chloride film and etching stops.
It may be that with electrical current, etching action can
continue through a porous chloride layer. The other thought
that occurs to me would be to wonder if by error, the transformer
is actually an AC one, instead of DC. If that were the case,
then you’d get etching on one half cycle, and an attempt to
replate on the other. Since, as I said, silver chloride isn’t
soluable, the redeposit part might be rather poor, yet still
lead to some sort of weird effects…

Just wondering…

Peter Rowe


#13

Hi Peter,

Thanks a lot for your comments. I thought that I was getting a
metallic salt of some kind, but it’s been a long, long time since
I took any chemistry courses.

There was no mix-up of the DC and AC terminals on the
transformer since they were clearly marked and only the DC
terminals (which I used) responded to the rheostat (I checked my
setting with a battery tester in order to run at approximately 12
volts).

The second project I did with this method turned out better
than the first because I checked partway through and found that I
was getting some bubbles between the silver and the layer of
deposited material. Removing the deposit in these areas seemed
to eliminate most of the bumps and lumps that dotted the
background in the first piece I had etched. At any rate, my
customer was happy with the finished product. I hope his wife
likes it as much when she finds it under the Christmas tree!

Elaine (MoonStones)


#14

Bobert,

I would like to check out a “real” electronic parts store for
the Ferric Chloride, thanks for the tip; great price! If I have
trouble locating one, maybe I’ll ask you for a source.

About your method of tilting the piece every 5 or 10 minutes, by
doing this are you able to avoid the textural marks that the
ferric seems to make in the etched areas? There can be a
disadvantage to disturbing a piece if it has very delicate
resists (certain soft grounds, for example) or very fine texture
where the resist is in the form of tiny specks. Just breaking the
surface tension with these resists/areas is enough to cause some
of it to come off. I think it depends on how long you’re etching.
I tend to do deep etches where I leave the peice in for 3+ hours.
To come back to it every 5 or 10 minutes would wreak havoc with
my work schedule.

Rene


#15
   About your method of tilting the piece every 5 or 10
minutes, by doing this are you able to avoid the textural marks
that the ferric seems to make in the etched areas? 

If ripples and waves are forming, use a more dilute solution.
Cut your mordant strength another 5-10 degrees on a Buame
hydrometer. Slower etch requiring more time, but more even for
large open areas.

   There can be a disadvantage to disturbing a piece if it has
very delicate resists (certain soft grounds, for example) or
very fine texture where the resist is in the form of tiny
specks. 

I don’t use grounds, but I use asphaltum. I slow dry it until it
is hard. On top of a refrigerator or with the oven pilot light
dries without melting it. K.P.


#16

A friend of mine who etches a lot of circut boards built a tank
that constantly rocks back and forth from a motor and gears
salvaged out of a broken tape recorder. He gets very thin traces
with this.

Ben Brauchler
Western NY State


#17

G’day Pam and others; If you mix ammonium bifluoride and battery
strength sulphuric acid, it will etch glass when warmed a little to
give a frosted effect. Because that mix results in hydrofluoric
acid, though dilute, it is best to work in rubber gloves with eye
protection, and close to a ventilator… A personal respirator would
be a good idea. Ammonium bifluoride is a white crystalline water
soluble solid that is very poisonous, but is not as noxious as
hydrofluoric acid. Just needs care. It might interest you to know
that my wife worked in an industrial lab for about ten years doing
analysis of silica and alumina using hydrofluoric acid in poor
ventilation… She is now 83.

However, I think that good results are obtained using a small sand
blaster. I would make a closed but well lit box with an exit filter,
two holes for hands and long rubber gloves to manipulate the job and
the little blasting gun. I made one such box from sheet aluminium
for weighing moisture sensitive substances (bacteriological culture
media) in conditions of zero moisture. – Cheers for now, John
Burgess;
@John_Burgess2 of Mapua, Nelson NZ