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Etching and red and brown stains on brass


#1

I’m hoping someone really knowledgeable will weigh in on this, but
for now here’s my suggestion.

Is the brown a real smutty sludgey layer? If it is, it’s that same
coat I get when etching brass in Ferric Chloride. You need a
chemical method of removal, rather than mechanical, to save your
texture. Use a good copper cleaner, like Penny Brite, or a homemade
vinegar /salt / flour solution (like Alma suggested here on Orchid,
the other day when I posted about running out of Penny Brite.). It
will take the brown right off. Then RINSE immediately and rub down
with dish soap: for some reason a new layer of brown (and some new,
prettier, but still unwanted colors) re-forms if you don’t wash it
well. I usually finish it off with a soak in water with a scoop of
baking soda dissolved in it. I was told this would neutralize any
ferric chloride lingering in the crevices. I soak overnight or a at
least a few hours.

(If anyone knows more about when and how long this should be done,
let me know too. I’m just doing what I was told.)

There’s 2 possibilities for the red stains you’re talking about.

One: if you’re soldering YELLOW brass, some of the copper in the
alloy migrates and makes those marks, which can look a lot like
little squiggles or lines, and seem to be fractionally below the
level of the surrounding brass. You cannot sand those out: they seem
to go deep inside. I have never been able to get rid of them, just
try to hide them with the patina. Use red brass whenever possible:
it doesn’t do that. Sometimes you’re stuck if using tubing, rod, or
machined shapes; they seem to be made only in yellow brass, which,
yellow brass multiple times or with high heat makes it worse.

TWO : If the red is more of a rosy flush, then what you have is
copper plating on top of the brass. If it’s on a large flat area,
sanding it off is still faster. Otherwise, use the Hydogen Peroxide
Pickle recipe in the Archives. It’s also listed on the Reactive
Metals website. Do this only after all soldering is complete. It is
stinky. It will also etch the surface lightly and leave it looking a
little grainy, or like you could see the crystal structure of the
brass. Which you then have to… sand off. But at least heavy
sanding will not be necessary. The red staining is worse if you
pickle the piece; you can wash it instead. But it will turn red from
the heat alone, too.

If you are going to have a patina in the low recessed etched areas,
then don’t worry about the copper stain in there. Most patinas will
work much better on the copper plate anyway: so use it to your
advantage. After the patina it won’t even look like copper in the
recesses. Just polish the high parts to look like the original brass
color.

Good luck…
Lin


#2

Yes, I know what you mean about that brown smudgy color after
etching with Ferric Chloride. I have been able to get rid of it by
soaking the etched piece in pure (not diluted with water) ammonia,
then scrubbing with an old toothbrush, or a brass or steel bristle
brush for the recessed areas. A scotchbright pad is sufficient for
the high areas… Then before enameling on the etched piece, I clean
it with my salt/vinegar/flour concoction, and neutralize with a brew
of ammonia, detergent, 409, and simple green. It works for me. Just a
suggestion. for those who have access to lemon trees Lemon juice
instead of vinegar is even more effective for cleaning the copper.
Probably more acidic.

Alma


#3

ZUD in the small kitchen cleanser type can at the supermarket or
hardware store, Also Barkeepers Friend from the same places. Zud
is a little less abrasive. You don’t need the abrasive action to
take off iron and copper stains – just the cleanser and a little
water and very light rubbing.

This is another plus for the Edinberg etch formula that adds a
little citric acid to the ferric chloride. see:

http://www.polymetaal.nl/beguin/mape/edinburgh_etch.htm

Related Pages:

jesse


#4

Help. I’m so frustrated I can’t see straight.

I don’t seem to be having much luck solving my brass "staining"
problem. When I solved one problem I seem to create another.

I tried several of the suggested Hydrogen Peroxide Pickles, both
using Sparex and/or vinegar and then the Sparex dip. They partially
worked (removed about 60% of the red stain and brown sludge) but did
leave a grainy texture which I don’t like (which is why I removed the
piece at 60% clean). But beyond that, it seemed to eat away the
solder seams at a faster rate, so now the joins are recessed which of
course looks horrible.

The solder is a whole other problem. I’m using silver solder because
I can’t find a brass one that will flow. I bought some brass solder
from Rio but the melting temperature is higher than the brass that
I’m using. I’ve had the same experience with other various bass
solders I’ve tried. With so many people making all kinds of things
out of brass it’s hard to believe there isn’t a brass colored solder
that doesn’t involve hording pre 1981 pennies(rolling one and using
it as solder was suggestion I was given). Any new ideas on the
subject?

I’ve made this same box in silver several times without incident.
But attempting to make it in brass was a complete disaster. Actually,
this project went more “wrong” then any other project I’ve worked on
in the last 6 years. This is driving me crazy; I’ve seen etched or
textured brass hollowware that is clean, polished, not grainy and
doesn’t have big silver seams. What is it soldered together with and
how is it cleaned up?

Is using brass really 200% more effort and work to use then silver
or am I just completely handling it wrong? I feel like I’m missing
some vital piece of

Thanks for any advice you may have and tolerating my venting. :slight_smile: It
wasn’t a good day.

Regards,
Sandra


#5
    Is using brass really 200% more effort and work to use then
silver or am I just completely handling it wrong? I feel like I'm
missing some vital piece of 

Yes. Brass is the devil. I never use brass.

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#6

Hi, Sandra,

Sorry to hear you are tearing your hair out over brass!

I’ve never constructed a brass box, but I (and my students) have
worked with it a good bit. We’ve always been able to clean it up
after soldering with the peroxide “bright dip”. I find myself
wondering whether part of the problem may be the brass you are
using. It seems to me that the kind called “nugold” suffers less
from copper-plating in heat than the others I’ve used, so maybe that
would help…

There actually is a brass-colored solder: gold. Not necessarily an
economical solution, but the amounts are pretty small.

Other than that, Indian Jewelry Supply sells “fos-flow #7”. It is
dark grey, but seems to take on color fron the metal it is used on,
oddly enough. I’ve used it on brass and copper and had it pretty
much disappear. It has a low melting point, as well. Plus, it is
very cheap.

Good luck on your project!

–Noel


#7
The solder is a whole other problem. I'm using silver solder
because I can't find a brass one that will flow. I bought some
brass solder from Rio but the melting temperature is higher than
the brass that I'm using. I've had the same experience with other
various bass solders I've tried. With so many people making all
kinds of things out of brass it's hard to believe there isn't a
brass colored solder that doesn't involve hording pre 1981
pennies(rolling one and using it as solder was suggestion I was
given). Any new ideas on the subject? 

Sandra, if your brass solder is not flowing, you’re not heating
it enough. I can’t imagine what brass sheet you’re using that
would melt before the solder (is it red brass? That’s what Rio
sells – 15% Zn, 85% Cu). The flux for silver soldering should work
fine with the brass, although if your box is quite large, you may
want to buy the black flux (available at any welding supply store)
which lasts longer at the higher heats you will need for soldering
brass.

I use paillons of hammered brazing rod for much of my brass
soldering. The color match is quite good, but it requires even
more heat than the available brass solders and will only work with
red brass, not the “standard” brasses that have a higher zinc
content (and possibly some lead).

Pennies are for trying to get a copper-colored solder for copper,
not brass. That is tricky, because their melting points are quite
close (but it does work for simple seams in copper).

If you don’t mind working with a cadmium-containing solder (cadmium
is dangerous… wear a mask for metal fumes and vent your area),
Indian Jewelers Supply still has some. The Easy-Flo does flow
very nicely, at a lower temperature, and it has a somewhat brassy
color.

As for the problem of the etched look, can you tumble-polish your
final product? It’s a lot easier than wheel-polishing.

All the best,
Judy Bjorkman


#8
Brass is the devil.  I never use brass. 

I love brass, work with it all the time, and my customers like it,
too.

There actually is a brass-colored solder: gold. Not necessarily an
> economical solution, but the amounts are pretty small. 

Right, Noel – it is a good color match, until the brass begins to
tarnish a bit. The solder line, however, will always stay bright.

Peace,
Judy Bjorkman


#9
   I tried several of the suggested Hydrogen Peroxide Pickles,
both using Sparex and/or vinegar and then the Sparex dip.  They
partially worked (removed about 60% of the red stain and brown
sludge) but did leave a grainy texture which I don't like (which is
why I removed the piece at 60% clean). But beyond that, it seemed
to eat away the solder seams at a faster rate, so now the joins are
recessed which of course looks horrible. 

I usually etch first, then solder. Peroxide pickles attack copper
bases, but not silver. It is a weak etch, which is why you get the
slightly frosted appearance. This is why it’s useful for lifting
firescale. But–since you don’t want it to etch your soldered seams,
you can use a quick brush up with some fingernail polish before
putting it in the pickle, which can be removed, after cleaning up
the stains from the pickle, with fingernail polish remover.

   The solder is a whole other problem. I'm using silver solder
because I can't find a brass one that will flow. 

A nicely colored brass solder is available from Rio, Thunderbird and
IJS. However, it’s not brass solder nor Foss-flo. It’s silver
solder, #45 and #30, which contains 45% and 30% silver respectively.
Their high copper and zinc content gives it a brass color that
closely matches red brass. It has a high cadmium content to lower
the solder flow temperature, and you must have adequate protection
from the fumes. These low-temp flow solders will prevent staining on
red brass soldering. This staining is probably the result of getting
your brass too hot, in order to solder with high-temp flow solders.
This causes the copper to rise to the surface from the alloy.