Nitric Acid

Jewelry Discussion
1

The recent thread Re: nitric acid has prompted me to ask some basic
questions…

Would someone please explain the “pros and cons” and “how tos” of
dealing with nitric? I have been given conflicting on
how to use it, when to use it and how to handle it. I have seen
people afraid to be in the same room as nitric acid as well as people
who are fearless around it. And, because a friend of mine had a
frightful accident (in which she could have easily lost her eyesight
or worse) I am very nervous around nitric.

Do you folks find it a frequently needed item in the studio? What do
you use it for? How do you store it? How dangerous or volatile is
it? ANY and ALL info would be appreciated.

Thanks, Alice from Wisconsin’s cloudless, cooler by the Lake,
eastern shores.

2

One place I know of to get nitric acid is Graphic Chemical and Ink
Company in Villa Park, Illinois. Their number is 800-465-7382. This
is a printmaker’s supply house, so they carry acids and everything
else for the art of printmaking. They may not have the strength you
require already premixed but you can mix it yourself. I hope you
have the right mask and ventilation… I make my etchings with it
and it is highly toxic.

By the way, everyone else, Graphic Chemical also has wonderful
engraving tools.

I do not work for this company. I have been buying my supplies from
them for years and they are a helpful, down to earth, friendly group.
If you have any techincal questions, ask for Dean.

Diana Widman at Birch Tree Studio

3

Hi Alice, You stated I am very nervous around nitric and gave a sound
reason.

Normally I don’t rant about chemicals, but I make an exception with
nitric acid. Your example is precisely why can’t caution people
strongly enough about using concentrate nitric acid. It is a very
strong oxidant and its fumes in high enough concentration can be
toxic. Why use it when there are much safer acids or mordents such as
ferric chloride or ferric nitrate (rhetorical question) when etching
is required.

In British Columbia nitric acid is considered a dangerous good. You
are prohibited by law from carrying more than (I believe) 250 mls
aboard a ferry unless you are a bona fide carrier.

The link below might help to inform you.

http://www.efma.org/Publications/NitricAcid/Section03.asp

If one is determined to use nitric acid that one must use eye
protectors. Take a pair of glass, sand them, put them on and now try
to do that fine bit of polishing or soldering.

Now let’s hear from the other side.
David in Victoria where finally it is sunny.

4 
    Would someone please explain the "pros and cons" and "how tos"
of dealing with nitric?

G’day Alice Sauer et al; I have worked with and around nitric acid
from when I became a lab assistant at the age of 14 - and I still
occasionally use it now at 80.

But let there be no mistake; nitric acid is a very hazardous
chemical, especially in untrained and unknowledgable hands. I discuss
the strong acid:-

  1. It is a very strong acid and as such will eat holes in clothing
    even when diluted down to 10%. If allowed to come into contact with
    flesh it must be washed off with plenty of water, but will leave a
    bright yellow stain which can only be removed by wear - or the
    application of pumice. If washed away quickly it will do no harm.
    When 15, I put my arm into a tall jug which I thought was empty, but
    was half full of concentrated nitric acid. After a good wash I was
    none the worse except for a bright yellow arm and hand which became
    it’s more usual dirty colour in a week.

  2. It is a very powerful oxidising agent. If a little is poured
    into warm, dried sawdust it will burst into flame. Same with pure
    turpentine. With oils it can possibly form explosive, and
    spontaneously flammable compounds.

  3. It constantly gives off a vapour of choking fume which is acid
    and poisonous and which is bad for lungs. It will eat away corks and
    rubber stoppers in a day or two.

  4. It dissolves (etches) copper and brass very quickly giving off a
    noxious and very poisonous brown gas called nitric oxide, or nitrogen
    dioxide; (NO2) very bad for the respiratory system. The acid does not
    dissolve iron easily, for it covers the surface of the metal in a
    coating of oxide which it penetrates no further unless strongly
    heated. This is used industrially and is called pacification.

  5. Nitric acid will easily dissolve silver, also giving off the brown
    poisonous fume, leaving silver nitrate, which can be crystallized
    out. A mixture of nitric and hydrochloric acids is called aqua regia
    (Royal Water) will dissolve gold, giving a solution of auric (gold)
    chloride.

  6. A mixture of nitric and sulphuric acids combines with many organic
    oily substances like glycerine to produce explosives such as nitro
    glycerine which are extremely sensitive to rough handling and explode
    violently. (Alfred Nobel began the Nobel Prize tradition to atone for
    inventing dynamite, which contains the substance.)

I have been given conflicting on > how to use it,
when to use it and how to handle it.

So handle it with care, wearing protective goggles with side pieces,
wear rubber gloves and a plastic apron, washing them afterwards. I was
never told about that as a lab boy, and topped up about 30 reagent
bottles of it every morning for several years with no protection at
all, except a cotton lab coat which was always full of holes. And
which we had to supply ourselves.

As it will quickly eat away cork and rubber, it used to be supplied
in glass stoppered bottles, but polythene plastic lasts well - and is
cheaper!

    Do you folks find it a frequently needed item in the studio?

Few jewellers use it. It is however, used in the famous ‘acid test’
for golden metals. Streak the metal on a bit of slate and look at the
streak; certain shades provide clues to the metal. Add nitric acid
to the streak, and again observation of the streak can tell one about
the carat value of the metal if a gold alloy

What do you use it for?

Etching, some cleaning up of jewellery; See above

   How do you store it?

In glass bottles with ground glass or polythene stoppers. Or
polythene bottles of heavy high grade polythene. Keep it in a cool
dark place away from the sunshine which will help it decompose. When
removing the stopper, avert the face (complete with eye protection) as
a little pressure may have built up, causing a small spray of acid. If
one has to use it often, it is preferable to store it in small bottles
rather than the 2� litre bottles I used to have to cart around the
labs. As when any acid is in frequent use, have a large plastic
bottle of baking powder (sodium bicarbonate) always handy. In the
case of spillage simply tip an excess of the dry powder over it, leave
a while, then sweep up the mess - which will still be a powder if
you’ve used plenty; it’s cheap enough. Wash down the drain (No it
won’t hurt the pipes, the septic tank or the sewer lines.) Later in
my laboratory life I supervised the cleaning up of smashed half gallon
bottles of conc. nitric acid; about 3 kilos of baking powder dropped
on the mess made it easy to clear up. (didn’t do the parquet flooring
much good though)

Well, there you are; I could even go on, but enough is sometimes too
much. If there is anything I haven’t covered, just email me
personally. – Cheers now,

John Burgess; @John_Burgess2 of Mapua Nelson NZ

5 
    Would someone please explain the "pros and cons" and "how tos"
of dealing with nitric?  I have been given conflicting information
on how to use it, when to use it and how to handle it.  I have seen
people afraid to be in the same room as nitric acid as well as
people who are fearless around it.  And, because a friend of mine
had a frightful accident (in which she could have easily lost her
eyesight or worse) I am very nervous around nitric.

Nitric is extremely hazardous. I think probably the only more evil
thing out there is Hydroflouric Acid.

If you handle it incorrectly, you can get many a problem. It is
toxic, very corrosive, and can burn you badly. It also fumes, and you
wouldn’t want to breathe it in.

    Do you folks find it a frequently needed item in the studio? 
What do you use it for?  How do you store it?  How dangerous or
volatile is it?  ANY and ALL info would be appreciated.

If you can live without it, do so. Keep it out of temperature
extremes, and tightly sealed. Only handle while wearing gloves, face
shield and breathing protection, in a well ventilated area.

Don’t mix it with ANYTHING but water. You can create a lot of ugly
chemicals (including explosives) with Nitric Acid. And when you mix
it with water, add acid to water ALWAYS, NEVER the other way around.
And do it very, very slowly, a bit at a time.

If you put a lot in, the dilution of the acid will release a lot of
heat, causing it to boil. When it boils, bad things happen.

Note that Nitric will dissolve silver, and will violently dissolve
copper. For example: tossing a penny into a cup of 50/50 nitric
solution will cause the acid to boil, and the penny will be gone in
about 10 seconds. Don’t do this, and treat it with respect, because it
has teeth and will bite.

  • darcy
6

Hello Marjorie (JL & MA Lord) I asked the very same questions re:
nitric acid just two months ago. Please check the answers I received
from:

Eileen Procter on 7/10/01
John Burgess on 7/11/01
David Popham on 7/11/01
and Darcy Brockbank on 7/12/01
You'll find wonderful, complete info there!

Alice in WI, sharing our nation’s heartache

7

Hi Susan, As an Analytical Chemist (my properjob!), and work with
concentrated acids all the time. I really wouldnt advise you to keep
your 100% nitric acid in the garage. The precautions you need to
dilute from the large container would be very specific and cause you
some severe safety concerns in the pouring and diluting. If you were
to dilute it, which I wouldnt advise. You would need a special
delivering pipette, safety goggles, thick nitrile gloves
,definately a fumehood( as conc Nitric Acid fumes alot), and other
protective equipment/lab coat/rubber apron, aswell as proper glass
containers etc.

I have seen some horrific acid burns , so extreme care needs to be
taken. My advice would be to donate it to the university, and buy a
strength more suited to your etching needs.

As for etching strengths, I havent done any etching yet, but im sure
other orchid members could advise you.

I you cant get the exact strength you need for etching from a
supplier, maybe you could order dilute Acid closer to the final
strength you need for etching.? And then carefully dilute that (
which would reduce the risk from your stock solution).

Handling guidelines for any acid strength are important to follow,
make sure you are near a supply of running water. Any spillages on
the skin should be flushed immediately with running water for at
least 15 mins before seeking medical help. The damage to the skin
continues fr a long time after the initial spillage. A spillage of
acid on a work bench should be neutralised with sodium bicarbonate
(NaHCO3) , baking soda which you should have nearby when working
with acids. In case of eye contact, promptly flush the eye with
plenty of water for at lest 5 minutes, and as soon as possible seek
medical help.

When diluting acids, ALWAYS ADD THE UNDILUTED ACID (OR STRONGER
ACID) TO WATER. NOT THE OTHER WAY ROUND. which causes dangerous
violent splattering and fuming. Add the acid to water slowly into a
glass heat-resistant container whilst striring with a glass rod. Take
care what container you are mixing in , acids and water together
produce heat which can crack the container,and you could end up
witha very dangerous spillage.

storage of Acids, concentrated or dilute should be well labelled,
in a well ventilated place, where it will not be subjected to heat.

Containers can be sourced from lab equipment suppliers such as BDH
or Fisher, you are looking for pyrex heat resistant beakers, and
they also sell safebreak glass bottles ( coated in plastic) for
storage of your diluted acids.

I hope I havent scared you with this posting, but Acids definately
need to be treated with respect and the correct safety controls
taken. If you had come accross a nasty Acid burn as I have, you would
have the upmost respect for these chemicals.

If you have any questions regaring the dilution factors/etc or
anything else dont hestiate to ask, I will try to answer them for
you.

play safely!

Nikky

8

Hello all… I was wondering if anyone could help me with a
question… I have made some rings out of silver chenier, and in
order to make them, I used copper wire inside of the chenier in
order to retain its form. I need the rings to be hollow, and know
there is a way to etch out the copper wire through submerging them
in a Nitric Acid bath, but am wondering if anyone knows the solution
ratios to use with Nitric Acid, as I am sure it wouldn’t just be
using straight Nitric Acid. Can anyone help me with this? I have
looked through my books and am not able to find anything.

Thank you
Catherine Chandler

9 
   I have made some rings out of silver chenier, and in order to
make them, I used copper wire inside of the chenier in order to
retain its form.  I need the rings to be hollow, and know there is
a way to etch out the copper wire through submerging them in a
Nitric Acid bath,

G’day Catherine; DON’T use nitric acid! It will dissolve both
copper and silver! Try using a warm fairly strong solution of ferric
chloride, but it will take time even if frequently stirred.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ

10

I can’t help with proportions but I wanted to urge caution with the
reaction between nitric acid and copper. It releases a red=brown,
very poisonous gas called nitric oxide. A few minutes of breathing
50 parts per million of nitric oxide in air is enough to start a
reaction in your lungs that can lead to death within a matter of
weeks.

I am not knowlegable enough to know whether the smell of the gas at
lethal levels is enough to give you warning. I did smell it once;
it is very acrid smelling. Hopefully, someone else can contribute
about dangerous levels of this gas and how to use the
process safely.

Howard
Eagle Idaho

11

I’m not sure how much of a help this is, but there is an acid that
you can buy at Radio Shack that etches copper. If you leave the
piece in long enough, it may etch out all the copper, but there could
be something more powerful that would do it faster.

12

Please forgive my intemperate response…

        A few minutes of breathing 50 parts per million of nitric
oxide in air is enough to start a reaction in your lungs that can
lead to death within a matter of weeks.

Where did this come from? I don’t think it is correct
at all!

First of all the reaction talked about only occurs when using
concentrated nitric acid. Etching away copper in the workshop uses
the diluted acid.

Nitric oxide is certainly an irritant, it can kill you instantly at
very high concentrations by dissolving in the liquid of the lungs and
forming an acid that scars and causes breathing difficulties - like
sulphur dioxide does. You should avoid breathing the fumes - but the
amounts of gas in a well ventilated room are very low (especially
with the weights of copper you are using.)

Last of all nitric acid will eat away the silver as well as the
copper.

I think it important that when we post here we really check our
facts and not repeat workshop mythology.

Tony Konrath
Key West Florida 33040

13

I apologize for not reasearching toxicity of nitric oxide before
sending my response. I depend a lot on my memory an haven’t much
time for research on weekday mornings. The point I should have
clarified in my original message is that the lower levels of
toxicity are rather rare and more chronic than acute. The lowest
acute death in mice was 320ppm.

Chronic effects have to do with progressive lung edema and/or immune
reactions in the lungs. It appears that these effects are more
treatable now than they were a few (too many) years ago when I
studied these subjects. This morining’s research did not verify my
original statement that 50 ppm could be lethal but I don’t believe
that I was too far off. The following is an excerpt from a MSDS
that I found using google. I would encourage anyone that has no
experience with nitric acid that intends to use it to read the
entire MSDS for nitric oxide. It is very interesting. Here is the
excerpt:

90 ppm: for 40 minutes has caused moderate irritation to the eyes
and mucous membranes and potentially fatal delayed pulmonary edema.
The delay may be up to 70 hours when symptoms of cyanosis (turning
blue), shortness of breath, restlessness, headache and frothy yellow
or brown sputum appear. If untreated, fluids or froth can flood the
lungs (i.e. drowning) or can be infected by viruses or bacteria
resulting in bronchitis or pneumonia which may be fatal to a
weakened patient.

88 ppm: LC50/4 hour inhl-rat.

70 ppm: for 8 hours has caused permanent corneal opacities
(blindness) in rabbits.

50 ppm: is moderately irritating to the eyes and mucous membranes
within 10 minutes and long exposure can cause permanent eye damage.
IDLH (Immediately dangerous to life and health).

30 ppm: LC50/1 hour inhl-guinea pig.

4-5 ppm: for 15 minutes will cause increased airway reactivity
(constriction of airways), airway resistance (more effort needed to
breathe), and decreased diffusion of gases in the lungs.

4 ppm: for 10 minutes anaesthetizes the nose so it can no longer
smell.

1-5 ppm: sweetish acrid odour.

0.1 ppm: for 2 hours can result in increased airway reactivity for
asthmatics or people with chronic bronchitis.

DELAYED SYMPTOMS Some individuals who had symptoms of acute exposure
with or without edema developed an immune reaction (bronchiolitis
fibrosa obliterans) 10 days to 6 weeks after exposure. Symptoms
include severe cough, cyanosis (turning blue), fever, hypoxemia (low
oxygen level in blood), reduced pulmonary function, decreased
pulmonary diffusion and X-rays may show fine scattered nodes in the
lungs. Also, lungs are vulnerable to virus and bacterial infections
for several weeks after exposure resulting in recurrent bronchitis.
If pneumonia sets in, there is a potential of death.

14 
        Please forgive my intemperate response.... I think it
important that when we post here we really check our facts and not
repeat workshop mythology.

Bravo! and ‘Good on you, mate!’ That wasn’t intemperate, it was damn
good advice. www.snopes.com is my favorite website for chcking ‘urban
legends’

David Barzilay, Lord of the Rings

15 
The following is an excerpt from a MSDS that I found using google"

Thank you - can you give me the source please? Tony Konrath Key West
Florida 33040

16

Here it is: Nitric oxide MSDS(Joshua B. Halpern)

An interesting thing is that the MSDS was an attachment to the main
paper. The main paper dealt with the myth that nitric oxide is one
of the most toxic gases known to man. It is not; There are gases
orders of magnitude more toxic. However nitric oxide is considered
immediately dangerous to life or health at levels below 100 ppm.

The main danger in the shop is trying to use it to dissolve any
significant quantity of copper. Low levels can dissolve beneath
contact lenses and cause blindness. My calculations (that would
need checking) is that my small room (30 cubic meters) could reach
toxic levels dissolving 3 to 4 grams of copper.

I do want to thank you for giving me incentive to research the
subject and improve my knowledge. I was wrong to various degrees
about 3 facts:

Brown gas is nitrogen dioxide, not nitric oxide. Both have similar
toxicity and both are released by the action of nitric acid on
copper.

50 PPM could cause death. I am not sure this is wrong but 90 PPM is
the lowest level of documentation I could find.

Certain death: The edema and or immune reaction is treatable by
modern medicine. Death is by no means certain. Death risk
increases if the effects are left untreated.

Thanks for the rigorous discussion
Howard Woods
Eagle Idaho