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Etching with salt solution


#1

Was: Difficulty sourcing ferric chloride

You could try a 7% pure salt in distilled water with a 1.5 to 9
Volt power supply like in this link:
http://www.navaching.com/forge/etching.html 

I just tried this and it etches sterling quite well! I have been
using a solution of phosphoric acid (Ospho) and distilled water and
a Radio Shack 13.8vdc power supply with excellent results.
(Instructions how to do this can found in the archives.) The salt
solution seems to work just as well. It might be a little slower, but
that’s just a feeling not an actual measurement. I’m going to have to
check this out a little more.

John
Juneau,AK


#2

That looks very useful. Thanks. What would you recommend for a resist
for copper or brass?

RC


#3
What to use as a resist on copper and brass

Answer: There are several things that you can use as a resist on
copper and brass when etching with a corrosive salt solution. When I
took print making in college we mostly etched large copper plates. I
found that I really liked using an even coat of black spray paint as
a resist for the back of my plates. Another option is to use clear
packing tape or contact paper. When using contact paper and packing
tape be really care full to get rid of all the air bubbles and make
sure that the edges are pressed down well. For the front of the piece
that gets the design you can use liquid asphaltum. You can buy this
from print making and art suppliers. Liquid Asphaltum can be painted
on the piece. You can also get it in a ball form, with this you have
to warm your plate and roll it on. When the asphaltum is dry you can
use a scribe and scratch through to the copper to create the design
you want etched. A black sharpie can also be used as a resist for
small areas. I am sure there are other things you can use too, these
are the methods that I am familiar with. Hope this was helpfull.


#4
I just tried this and it etches sterling quite well! 

Hmmm… I just tried it, and the silver got covered with a blotchy
crust that caused the background to come out looking like it had
leprousy. I used kosher salt (what I had) and my anodizer at about 3
amps and 10 or 12 volts. It did etch, but the background was
seriously awful. What did I do wrong?

Noel


#5

I already warned that you can’t use this with choroids as the
electrolyte on SILVER… Common Salt is sodium chloride - sea salt
has a lot of magnesium chorded which isn’t any better. The reason is
that silver forms a solid precipitate with chlorides --the crusty
mess. It can work on copper and brass.

jesse


#6

Noel:

I just tried it, and the silver got covered with a blotchy crust
that caused the background to come out looking like it had
leprousy. I used kosher salt (what I had) and my anodizer at about
3 amps and 10 or 12 volts. It did etch, but the background was
seriously awful. What did I do wrong?

I tried it too. Mine etched but only so slightly that it polished
off right away. I tried again and let it etch for longer (2 hours)
and it ate through the copper wire that was suspending it in the
solution and it fell to the bottom in the salt residue and got
totally goofed up. Furthermore, I used Permanent marker only to find
that the part that was etched was totally black, the permanent marker
was easily removed using rubbing alcohol, but I couldn’t get the
black out of the ever so slightly etched part. Finally just sanded
the whole thing off so I would have a piece of scrap silver to try it
again. It won’t etch much longer than 3 hours as the cathode needs
constant cleaning, and after 3 hours, the solution is nearly copper
colored and is just not strong enough to etch. I wrote to Ron who
wrote the article in Art Jewelry and he said he had etched silver
with it and had a moderate result after two hours.

So don’t know, guess I will keep trying as long as the scrap holds
out and eventually guess it will work. Tried using nail polish for
the resist and while it kept the background clean, it didn’t scrape
off too well for the design I wanted to etch and the piece didn’t
etch all that well either. I was using 20 ga metal scrap so don’t
know if that had anything to do with it or not.

I’ll try again this weekend when I have more time to worry with it
and “watch the pot”.

K


#7
I tried it too. Mine etched but only so slightly that it polished
off right away. 

Mine etched noticably (though maybe half the depth I’d like) in 20
minutes or so. My resist was a photocopy on acetate that I
transferred with an iron, and it held up just fine. So I guess what
you did wrong was different from what I did wrong. It sure would be
nice to etch without those nasty chemicals, but there’s probably a
reason (or three) people go on using them.

Noel


#8

I used copper soldered onto the corner of my sheet for the first
piece I etched, and I was not impressed. The copper, although
seemingly well masked, still gunked up my solution quickly. I think
it’s best to only use metals of the same kind – I just now leave a
"tab" of the sheet I’m etching to attach my lead to. Also, if your
alligator clip was touching the water at all, it was being etched
away, too, contaminating your solution.

I used the warm 7% salt solution for several of my first etchings. I
wasn’t that excited by the results – it didn’t etch particularly
evenly, and was leaving some areas that didn’t even have resist
unetched. We got good results with pieces that had very fine lines,
and not a lot of them. Overall, though, it was just a little too
corrosive, I think. Last night my husband and I tried warmed sodium
bisulphate (Sparex under the brand name, but waaaay more expensive
than regular ol’ sodium bisulphate), and we got really nice results.
The etch was a bit slower, but much more even and the nice thing is,
it basically pickles the work, so you don’t have a thick layer of
corrosive crud gumming up your work. The resist also doesn’t seem to
get “consumed” and undercut like it was with the salt. It is, of
course, irritating to lungs and mucous membranes, so doing this
under a hood or outside would be the most desirable.

It’s also important to keep an eye on your amperage. If you’re
pushing too much current, it can blow out your resist and just
create a mess. We have been using PnP Blue, touched up with Sharpie
in the small areas, and nail polish in the larger ones. Packing tape
or Scotch tape on the backs seems to be working just fine. A
fiberglass brush works well for removing resist. We’re still in the
learning process, but with each piece it seems to be getting better!

Jennie


#9

I used the 7% salt solution for several of my first etchings. I
wasn’t that excited by the results – it didn’t etch particularly
evenly, and was leaving some areas that didn’t even have resist
unetched. It was just a little too corrosive, I think. Last night my
husband and I tried


#10
Last night my husband and I tried warmed sodium bisulphate (Sparex
under the brand name, but waaaay more expensive than regular ol'
sodium bisulphate), and we got really nice results. 

To my mind, if I have to use toxic chemicals anyway, I’ll just stick
with nitric acid. It works extremely well, no messing with electrodes
and voltages. And, by the way, I find a paint pen best for touch-ups,
much much better than Sharpie. And if you pre-etch for 1 minute in
nitric before applying the resist, the resist will hang on better.
So, I’m confused. Salt doesn’t work with silver? Someone said they
got good results. I’ll try some more as soon as I get a chance, but
wouldn’t be averse to benefiting more from other people’s experience!

Noel


#11

Noel,

I’m the person that said I got good results etching with salt
solution. Since I said that, I have learned that the results are
entirely unpredictable. My first try, a dragonfly on sterling turned
out good. Since then I have had hit or miss results, mostly miss. For
some reason, the PnP gets eaten up most of the time resulting in a
ruined piece.

I like electro etching but have given up on the salt solution and
I’m going back to phosphoric acid.

John
Juneau, AK


#12

Hi Noel,

I am nervous about nitric. Although I know it’s not any worse than
most of the acids, I got a pretty nasty burn from it (in a much
different application), and have been leery of it since. I suppose
there’s no time like the present to get over that… but, anyway…

I am going to mosey on down to Artisans today and see what all they
have in they way of paint pens. I’ve seen them recommended many times
now, so I think I’ll buy a variety and see what works best. I do like
the Sparex/electro-etching, as it doesn’t seem to eat through the
resist too badly, if at all.

The salt DOES work with silver, but it can leave behind a thick,
nasty layer. The first pieces I tried in the salt water had large
areas of open surface to be etched, and I didn’t get a particularly
even etch on them. I think the build-up of crud probably contributed
to this. The ones with the finest lines did just fine in the salt
solution – our 8-year-old daughter is in love with that Pokemon
character Pikachu, so we made her a pendant with a line drawing of
the little thing on it. It came out gorgeously in the salt water.
Anything big – not so much. The sodium bicarbonate didn’t do much
of anything (we’d read that someone used baking soda in hot water
with good results somewhere on a website – they must have some
awesome baking soda!). I’m still doing a lot of experimenting… I
was in veterinary medicine for many years prior to this, so I think
it’s replacing the lab time I would normally have. :stuck_out_tongue: I’ll continue
to post as I come up with more on different trials.

Jennie


#13

There is an article in the current Jewelry Art Mag on etching copper
in a salt solution. Anyone tried using their directions? I’m trying
to gather the materials to give it a whirl. Would love to hear from
others who have used this method with copper successfully.

Beth in SC


#14

Hi all,

I use diet coke when electro-etching sterling.

Cheers,
Larry Bima


#15

I’m the person that said I got good results etching with salt
solution. Since I said that, I have learned that the results are
entirely unpredictable.[snip] For some reason, the PnP gets eaten up
most of the time resulting in a ruined piece.

If the etching part works, but the resist comes off, you might try a
different resist before you give up. I iron my image onto the silver
from a photocopy on acetate (overhead projector or report cover
sheets). I pre-etch the silver slightly (one minute in nitric acid,
dunnoin salt) before applying the resist. This alone might change
your results.

Noel