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Etching and ammonia


#1

I am wanting to etch at home and have a dilemma of where can I buy
industrial strength ammonia if I am not a business? Here in the KC
area, the company I fill tanks with told me that NO ONE will sell
ammonia to an individual. One book I have says you can use baking
soda instead. Can Iuse baking soda?? The Ganoksin site has a few
articles, but will not let me copy and paste.

I am using the kind of already mixed and reusable liquid etching
mordant from Radio Shack. Can I use baking soda with the same
results as ammonia?

thx!
brenda


#2

Hi Brenda! Just a few wks ago i was also on a delemma, neeeding
amonia, to clean a white gold ring i repaired 4 someone. What worked
4 me, although the process takes longer than wot it wld with amonia,
was apple cider vinegar! Hope u find help where u r. I’m in the UK!

Hilda


#3

Brenda check out the orchid archives - you will find lots of article
about etching copper.


#4
I am wanting to etch at home and have a dilemma of where can I buy
industrial strength ammonia if I am not a business? Here in the KC
area, the company I fill tanks with told me that NO ONE will sell
ammonia to an individual. 

That’s pretty much the case these days, since anhydrous ammonia
(your industrial strength) is one of the key materials required in
the making of methamphetamines. So to combat the proliferation of
kitchen drug labs, getting that ammonia is now very very difficult
unless you’ve a legitimate and proven business reason.

But what the heck do you need ammonia for anyway? It’s NOT what you
use to etch metal. Ammonia is a great cleaning agent you can use to
de-grease the metal before applying whatever you are using as an etch
resist, but it’s not needed. any good cleaning agent will work. One
of the best is simply scrubbing the surface with pumice powder until
you get it “water break free”, meaning water flows over it without
pulling away or beading up on areas. And this level of cleaning is
only required for photo etching or some resists that are especially
sensative. Many resists don’t require much cleaning at all, and the
actual etching does not either.

The etching is done with acid mixtures. For copper, generally a
ferric chloride mix is used, but you can use nitric acid or
hydrochloric acid as well, and those work well too for metals like
bronze and brass. For silver, nitric acid or it’s salt, ferric
nitrate, are the usual etchants. You can get ferric chloride solution
for etching copper from electronics supply companies. It’s used to
etch circuit boards. For the others, any chemical supply shop can
sell it, as do some jewelry supply companies. Even your local
pharmacy can order small quantities of the acids, unlike your pure
ammonia.

One book I have says you can use baking soda instead. Can Iuse
baking soda?? 

Yes, if you’re out of toothpaste. Or if you’re neutralizing odors in
the fridge or cat box. Also it can be used to help scrub metal clean.
In etching, it’s use would be in neutralizing the used acid prior to
disposal. You could also dip an etched piece in a baking soda
solution to neutralize any acid on the piece, but generally, just a
good rinse would do the same.

The Ganoksin site has a few articles, but will not let me copy and
paste. 

PDF files often are locked to not let you alter or edit them, so
they usually don’t allow cutting and pasting unless you’re using
professional level PDF software rather than something like the free
Adobe PDF reader. But that reader, while it may not allow cutting and
pasting, certainly does allow you to print the document. So try just
printing the whole page. The PDF reader or web browser will send the
document to your printer’s software, and often you then get a print
window that will let you determine things about the print task,
including which pages or range of pages you wish to print. Use the
print preview functions to figure that part out if it’s many pages
long and you don’t want to just print the whole article.

I am using the kind of already mixed and reusable liquid etching
mordant from Radio Shack. Can I use baking soda with the same
results as ammonia? 

Your Radio Shack solution is ferric Chloride as described above.
Works well for etching copper. It contains no ammonia, and has
nothing to do with ammonia chemically (or anything to do with baking
soda either). Neither ammonia or baking soda is required to etch
metal with ferric chloride.

Etching happens with acids or acid compounds that can dissolve the
metal. Both ammonia and baking soda are bases. They neutralize acids,
and don’t etch metal. (one exception to that statement is that
cyanide compounds can be used to etch gold and silver alloys, and
cyanide is a base. But this is unusual for bases. Most don’t react
much with metals. And I really don’t suggest you try working with
cyanides at your experience level. Besides, they too can be
difficult to purchase)

By the way, high strength ammonia is not something to handle lightly.
Really really nasty stuff if you don’t know what you’re doing (as I
suspect may be the case here…)


#5
But what the heck do you need ammonia for anyway? It's NOT what
you use to etch metal. 

It etches copper beautifully, it is what we used to use to etch
copper from printed circuit boards at HP wen I was a plating shop
tech in the early 70’s. But it is way too nasty to use in a home
studio. You truly need industrial strength ventilation or it will
seriously injure your lungs and could potentially kill you.

James Binnion
James Binnion Metal Arts


#6
By the way, high strength ammonia is not something to handle
lightly. Really really nasty stuff if you don't know what you're
doing (as I suspect may be the case here...) 

Doubled and re-doubled, Peter. There’s a good reason household
ammonia is only 5%, while industrial ammonia is 95%. I worked with
that (and anhydrous) in my younger days, and have had the burns to
prove it. There’s a reason for its use being reduced year by year…

Blessed be…


#7

I have a gallon on industrial strength ammonia that I got years ago
at a janitorial supply place, I think it’s 27%, strong stuff. From
what I’m reading here, it sounds like it’s hard to get now. The other
thing about etching. I use H2O2 and a little sodium bisulfate
(pickle). Throw it away when you’re done, it doesn’t keep. Etching
for pennies, works like a charm. It etches copper and silver. And
watch it so it doesn’t bite too much.

Tim M.


#8

Tim,

I have a gallon on industrial strength ammonia that I got years
ago at a janitorial supply place, I think it's 27%, strong stuff.
From what I'm reading here, it sounds like it's hard to get now. 

Wow, 54 Proof beverage, aged in aluminum for over a decade? Don’t
throw it away! I know this friend from Vega 5, a Jovian class
planet, who I think would really appreciate the stuff to take with
him to the next Superbowl. It would probably go well with a plate of
Vegan hot-dogs and Vegan chocolate chip cookies.

Andrew Jonathan Fine


#9

Tim,

H2O2 (hydrogen peroxide) and pickle to etch metal? Seems so safe and
innocous why don’t we all know about this? What strength H2O2 do you
use? Can’t wait to try this!


#10
H2O2 (hydrogen peroxide) and pickle to etch metal? Seems so safe
and innocous why don't we all know about this? What strength H2O2
do you use? Can't wait to try this! 

Most of the rest of us, I think, who’ve followed orchid for a while,
DO already know this, and you may too, although it may not be with
the word etching. However, it’s not just peroxide. It’s a mix of
peroxide and sodium bisulphate pickle. You mix up new, ordinary
strength pickle, warm, and add some peroxide. The more concentrated
stuff you get from beauty supply shops works best, rather than the
drugstore version, which is so dilute it has almost no peroxide in
it. Proportions aren’t critical, just add a glug or two to your
pickle container (it’s mostly still pickle with peroxide added,
rather than half and half, etc) The peroxide acts to increase the
ability of the sulphate ion in the pickle, to dissolve copper based
alloys. In effect, you’re super charging the pickle to behave a bit
more like actual sulphuric acid (which will also etch copper alloys
just fine) instead of the more benign sulphuric acid salt that it
is.

We normally don’t think of this as an etchant. Instead, it’s been
frequently recommended as a more active pickle that is capable of
removing the copper color stain on brass after soldering, or on
silver that’s been accidentally pickled along with iron to plate it
with copper. But that, of course, means the peroxide/pickle mix is
dissolving copper, which means it would work too, as a gentle
etchant.

Peter


#11

Or look to a chemical supply company in a major city. You may meed a
sales tax license, letter head to prove you are a business. Look for
Aqua Ammonia Solution 26 Bume. (Baume is a density measurement.) You
will want to pick it up, shipping is not practical. We use Hills
Brothers Chemicals in the southwest.

Bill
Reactive Metals Studio, Inc


#12

Hi dear friends, where could I find more on this topic ammonia +
peroxide for etching, I use nitric acid ( very dangerous and toxic)
mostly on copper and brass and every thin in behalf of safer methods
is welcome.

Regards,
Thor Hedderich


#13

Thor,

where could I find more on this topic ammonia + peroxide for
etching, I use nitric acid ( very dangerous and toxic) mostly on
copper and brass and every thin in behalf of safer methods is
welcome. 

Apparently you have misunderstood the thread’s topic. The original
poster wondered where she could find industrial strength (anhydrous)
ammonia, since she was under the impression that it could be used in
etching. The rest of the thread since then has branched off from
this, including mentioning the use of peroxide mixed with sodium
bisulphate (like Sparex) pickle as a supercharged pickle which will
lightly etch copper.

But the thread has been a little confusing.

The bottom line is that Ammonia is NOT normally used for etching,
either with, or without, peroxide. Anhydrous ammonia is sometimes
used in industry, such as in etching the copper on electronics
circuit boards, as Jim Binnion pointed out (which I hadn’t known.
thanks Jim), but be aware that anhydrous ammonia is an extremely
toxic and dangerous material, which can be safely used only with
proper ventilation and usually, industrial equipment. It’s not used
in jewelry work for etching. Ammonia does have some potential uses in
refining and in photography or the refining of silver containing
photo paper, since ammonia is able to dissolve silver chloride, which
is not generally soluble in water. But this does not have, so far as
I know, any application to etching for jewelry use. It is also used,
when dilute, as a cleaning agent, such as in many household
cleaners, and it can be used, again when dilute, in some methods of
putting blue or green patinas on various metals, especially copper,
bronze, and brass. As anyone who’s used it for cleaning knows, even
when very dilute like this, the odor can be noxious, and if used in
closed spaces without ventilation, even dilute ammonia has safety
issues.

As I noted above, hydrogen peroxide can be added to ordinary pickle
to make it more aggressive. The most common use is when people have
accidentally had some iron in contact with their silver when
pickling, which can leave a copper coating, or when brass is soldered
or annealed, which leaves it with a copper color instead of the brass
color. In both these situations, the peroxide/pickle mixture will
etch the copper enough to remove that, without damaging the silver.
With brass or actual copper, it does continue to attack the metal.
Whether this would be useful for actual etching, where some depth of
cut is desired, is questionable, but you could try it.

For safer alternatives to nitric acid for etching, you can use
ferric nitrate, an acid salt of nitric acid. This is actually a
preferred etchant for silver, since it cuts more smoothly with less
undercutting.

For etching copper, rather than nitric acid, you can use either
sulphuric acid, though this is not that much safer than nitric acid,
or more commonly, an acid salt of sulphuric acid, ferric sulphate.
This is a dark brown solution, which you can buy as a dry chemical
and mix with water, which makes shipping it much easier. It’s
commonly used in electronics as the etchant used to remove copper
from circuit boards, and can be obtained from electronics suppliers,
the sorts of companies that sell to hobbyists and experimenters who
wish to make their own circuit boards. Ferric sulphate does not have
the risks of really nasty fumes that sulphuric acid or nitric acid
does. It still is acidic, of course, and should still be used with
ventilation, and rubber gloves, but this would be expected. Either
way, it’s much safer and easier to use and store than are the
straight acids.

Hope that helps.
Peter Rowe


#14
The original poster wondered where she could find industrial
strength (anhydrous) ammonia 

Yes and this in itself was a misunderstanding, Anhydrous ammonia is a
gas or if stored at high pressure or low temperature it can be a
liquid but it begins to boil at -33 C. Anhydrous means no water.
Liquid ammonia the OP was looking for is ammonium hydroxide which is
actually ammonia gas dissolved in water. This is around 10 percent
for household ammonia and the high strength stuff we used for etching
is around 30% if I remember correctly.

James Binnion
James Binnion Metal Arts


#15
For etching copper, rather than nitric acid, you can use either
sulphuric acid, though this is not that much safer than nitric
acid, or more commonly, an acid salt of sulphuric acid, ferric
sulphate. 

I think more often folks will use ferric chloride (iron salt of
hydrochloric acid) for etching copper and brass and ferric sulfate
for zinc and steel

James Binnion
James Binnion Metal Arts


#16
I think more often folks will use ferric chloride (iron salt of
hydrochloric acid) for etching copper and brass and ferric sulfate
for zinc and steel 

Thanks for catching that, Jim. I knew that, but the typing fingers
sometimes have a mind of their own… I’ve used ferric chloride
often enough. Call it a senior moment… And one might add that
hydrochloric acid itself will also etch copper…

Peter


#17
The original poster wondered where she could find industrial
strength (anhydrous) ammonia 

It’s bee a few years since I’ve done this, but some architects used
to print their larger blue prints with printers that used ammonia in
a very pure form. I believe the fumes were the necessary element for
these units to work. When the ammonia was spent they had to dispose
of it by pouring it down the drain or sending it out to be disposed
of properly. I would use a half cup per ultrasonic bath plus soap
and would be stronger than any other available. I buy my current
ammonia at the grocery store. Not as concentrated but still adequate
for cleaning.

This ammonia was available for free and was the most concentrated you
would ever find. It still worked fine for all jewelry applications.

I think the more modern printers don’t need ammonia, but you might
call some local architects and ask. There may be some old units
still being used and a new source for possible free ammonia in its
strongest form.

Best Regards,
Todd Hawkinson
Southeast Technical College


#18
It's bee a few years since I've done this, but some architects
used to print their larger blue prints with printers that used
ammonia in a very pure form. 

Yes that is the 30% form of ammonium hydroxide.

James Binnion
James Binnion Metal Arts


#19

I can’t imagine why any one would even dream about etching copper
with ether stronger (28%) ammonia, a standard industrial water
solution or anhydrous ( 100%) liquid ammonia.

neither is friendly a material !! copper does react with ammonia but
— The reaction product will dissolve cellulose. This is the basis
of the old viscose rayon process. AS far as I know there are no
working viscose plants in the US.

You may be thinking of ammonium persulfate. This is used by some for
etching Printed circuit boards:
http://www.ganoksin.com/gnkurl/4e

An excellent on line guide to etching is :
http://www.ganoksin.com/gnkurl/4f

Etching is a common technique for making art printing plates. The
printmakers have done a lot of the work in developing safe
techniques.

The product may be different but process is the same. This site
covers everything except etching silver. Silver is not a good
material to use with chlorides but the galvanic method works fine,
but you must use a non chloride mordant. Ammonia may be a bit tricky
as it will strip some resists.

jesse


#20

Ammonia simply causes the fats, waxes and greases present on
materials to saponify (turn into soap.)

Its the same type of reaction that we use in making soap at home
(lye plus a fat.)

Almost any alkali (sodium hydroxide for example) will work in this
way - but a weak solution of ammonia is the safest. Sodium
hydroxide, for example, will also attack metals.