I asked a little while ago about safe etching solutions but got no
responses. I work in a room where the only means of ventilation is a
window and a fan so I don’t want to be using any solutions that are
particularly harmful to breath. I have looked through the archives
but haven’t found anything that answers my question - although,
perhaps I am just using the wrong search terms?
I have looked up the website for an electronics retailer in my area
and have found that they sell Ammonium Persulphate and Ferric
Chloride for etching circuit boards… can anyone shed any light on
how well either of these would work with brass and silver -
especially how deeply they would etch if they would etch at all?
Also, and importantly, are these solutions relatively safe to use?
I use pool acid/salt for my pickle and so haven’t tried the various
pickles available from suppliers - might one of these pickle
solutions do the job? My local jeweller’s store has in their online
catalogue a pickle solution that they say does the same work as
sulphuric acid without the hazards - but they don’t list the
"ingredients" in the solution. Any ideas what this one would be and
if it might be useful? Also, what about citric acid - is this strong
enough to do an etch?
and have found that they sell Ammonium Persulphate and Ferric
Chloride for etching circuit boards... can anyone shed any light
on how well either of these would work with brass and silver -
Ferric Chloride will etch copper, not silver. Don’t know about
brass. Yep, pretty safe to use. Try searching the archives on just
ferric chloride. Lots of info. there and on the web in general.
I use pool acid/salt for my pickle and so haven't tried the
various pickles available from suppliers - might one of these
pickle solutions do the job?
There has been a lot of discussion on this very issue quite recently,
in fact.
If you go to www.ganoksin.com and search for Etching in the 2005
archive, you will find 174 hits, including these few. I can’t paste
the entire thing in here, of course, but if you do that search, you
can read the rest of the articles and discussions on the subject, and
there may be even more if you search the entire archive. The thing
is, you can’t go by the title of the discussion because of something
called Topic Drift which is the nature of Internet discussions: we
start out talking about one thing and pretty soon we are off in yet
another direction:
Re: [Orchid] Rio’s Etching resist problem
Etching sterling with ferric nitrate
Etching on Metals
Silver Etching Supplies
The bottom line is, though, that using any etching solution in an
environment without adequate ventilation is a bad idea. The area I
work in has better ventilation than what you describe for your work
area, and there is no way I would use nitric acid - one of the
solutions that works for silver - inside unless I had a huge
industrial ventilation system. I can’t speak from personal experience
for ferric nitrate, which I haven’t tried yet. And, wearing a mask is
not a solution, as you will discover in reading these articles. There
is no mask that is safe for nitric acid. Here is the pertinent quote
from one of the articles:
Inconsistent Etching Results
I purchased an AOSafety respirator at my local hardware store but
couldn't find any about whether or not it worked with
nitric acid on the box or on their Web site. So I called them and
they told me that it wasn't possible to make a respirator that
worked with nitric acid because the cartridges use charcoal and
there was no way to get the nitric molecules to attach to the
charcoal. So now I'm wondering whether the person I talked to knew
what they were talking about. Does the package of your respirator
say that it's for nitric acid?
After doing some research, they don’t make a mask for this type of
nitric acid usage, but you should be using the bath under a hood or
with very good ventilation. For higher concentrations of nitric acid,
they tell you to use a self-contained breathing apparatus. But if you
are working under a ventilation hood you should be fine. I usually
don’t breath when I’m putting my plate in and out of the bath. And I
try not to look in the bath because it irritates the eyes. This info
came from MSDS sheets, NIOSH, and 3M. The package of my respirator
cartridges (with P100 filter) actually does cover other acids but not
nitric.
Pickle solutions will not give you a satisfactory etch. Pickle mixed
with peroxide, used to remove copper from silver or brass, will etch
a little, but the fumes are no less unpleasant than typical etching
mordants, maybe worse because it must be hot. It is probably safe to
assume that anything that can eat through metal is not beneficial to
breathe.
That said, ferric nitrate is much less fume-producing than nitric
acid, albeit slower. It is used, like nitric acid, to etch silver.
Ferric chloride, used to etch copper, will do just fine on brass as
well, and it seems pretty innocuous, on the whole. I would still
keep a lid on it, and use it right in front of your window fan (with
the fan blowing out).
Citric acid works just fine as pickle (though it will not etch-- a
good thing, on the whole). I have been using it for a couple of
years now with no problems at all. I don’t recommend breathing it,
either, but better that than normal pickle or pool acid.
I have no experience with ammonium persulphate, can’t comment on it,
but see last sentence of paragraph one.
an anyone shed any light on how well either of these would work
with brass and silver - especially how deeply they would etch if
they would etch at all? Also, and importantly, are these solutions
relatively safe to use?
Ferric Chloride will etch brass, nickel silver, and copper. If
possible, hang the metal upside down or lay on the green kitchen
scrubby mesh. This helps to keep the sludge from staying on the
metal and slowing the etch. You can get a deep etch. I know nothing
about the others as far as etching a pattern.
Many of our processes have hazards inherent in the use of them. Use
common sense and ventilation. I think that a lot depends on how much
etching you are going to do.
Ferric Chloride will etch brass, nickel silver, and copper. If
possible, hang the metal upside down or lay on the green kitchen
scrubby mesh. This helps to keep the sludge from staying on the
metal and slowing the etch. You can get a deep etch. I know
nothing about the others as far as etching a pattern.
Can I ask that you please be cognizant of where your fan blows the
products of your work? I have neighbors that do NOT appreciate
poisonous fumes, and neither do I. In addition, I have strong
allergies to citrus products - and don’t particularily like arriving
at the emergency ward at the local hospital, unable to breathe. Well,
I’m through venting now (pun intended).
I know from bitter experience that sparex spiked with hydrogen
peroxide will etch the heck out of brass. I once made a nice brass
watch chain and dropped it in a fresh batch of the above. Seemed to be
reacting a little slow so I went off to have lunch, which turned into
martini hour and… well suffice it to say that I ended up with a
chain that looked like it had been retrieved from a sunken pirate
ship: deeply corroded and etched away. I tried the same solution on
a brass buckle, painted it on this time using packing tape as a
resist, and it did the same again. It’s crude and the etch will be
very pitted and uneven but it does work.
I use Ferric Chloride to etch copper, brass and bronze. I use Ferric
Nitrate to etch sterling silver. These chemicals are often referred
to as “non-acid” and “non-toxic” etchants. But they are corrrosive
salts - so much be treated with caution and care. From what I read,
there are no appreciable dangerous fumes from either etchant. If you
are interested I have notes on my website about etching with ferric
chloride. Ferric nitrate works much the same way only seems to take
much longer to etch silver.
You might also search online for the name Keith Howard. He is a
printmaker who has done a lot of research on non-toxic etching and
printmaking. Also search the Orchid archives for “Edinburgh Etch” -
an etchant using ferric chloride with citric acid added.
One source of about brass etching is the model railway
hobbyists. Model railroad enthusiasts photoetch thin brass to make
custom trains & carriages as well as fine accessory bits & pieces.
If you do a search on photoetching or photoetching model railroad you
will find several interesting links. Try the search with “photo etch”
as well as photo etch “model rail” as well as “model railway” as well
as “model rail way” as well as “model rail road” etc The quotes are
intentional as they cause the search to be for a phrase and not just
the words scattered through an artical. You want to search on the
railway, railroad, photoetch as both a single word & split as two
seperate words as common usage can be either. I think that you will
find that covers what you want.