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Redoing a failed patina


#1

Hi folks–

I’m brand new here, and I hope I’m not re-asking a question that’s
already been thoroughly discussed. If it has, feel free to point me
to the relevant material in the archives.

Anyway: I did my first patina yesterday. I’m making a bracelet from
8 segments of 20-gauge copper sheet, and attempted to give them a
blue patina using ammonia and salt water. The results were… well,
less than great. “Failed” may be too strong a word, but only one of
the 8 pieces was completely covered in blue, and only on one side.
The rest had just patches of blue, with generally less than 50%
coverage.

So I’d like to try again. The main question is, can I just apply
more salt and set the pieces in the ammonia fumes again, or do I need
to remove the patina I’ve got and start over from zero?

The other thing I’m not satisfied with is that I spent a fair amount
of time stamping a texture in the metal, but the patina completely
obscures the texture in most places. Can I lightly polish the piece
(for example, with a green 3M bristle disc) and keep the patina, but
also expose the texture? If that means having patina only in the low
spots, and bare metal in the high spots, I’m okay with that. I can
experiment, of course, but I thought I’d ask as long as I’m here.

Oh, one other thing: does ammonia lose its potency as it evaporates?

Thanks in advance for your insights!
Matt Gushee


#2

I’m certainly no expert with patinas, but thought I would share my
experience with the same patina compound you used.

I was trying to make a blue patina on copper chain. However, I left
the copper in there too long, and it came out with a heavy bright
blue coat that was almost hairy. I also had spots that were not
covered (that’s because I failed to clean the copper thoroughly
first.) If I had attempted a second patina over the first in order to
get the coverage, it would not have worked. The coverage failed due
to dirt or oil the prevented it from adhering. So, to answer your
question, can you just do it again, “no.” You must remove all the oil
from the metal first.

First, I tried removing the patina with a wire brush, but it left a
lot there in the crevices. Then I tried tumbling it, but that still
left some. Then I soaked it in an acid cleaner, which worked. So,
that put me back at step 1 and cleaned the metal, so it was ready to
try again. I don’t remember why, but I put the thing back in the
tumbler. That gave me 100% perfect patina coverage, because a lot of
the patina was left in the shot, which adhered to the metal perfectly
100% because it was cleaned properly.

It did mess up all following tumble jobs because the shot applied
patina to those items also. I think I’ve tumbled about 20 or so more
times, and have had to clean up each job with acid cleaner
afterwards, but it appears that my shot is now finally clean again.

Lessons learned: 1. clean the metal first with an acid cleaner to
remove ALL oils and other things that can inhibit the patina, 2.
don’t leave the metal in the patina mixture for long without checking
it 3. buy some shot cleaner

Since then I did buy a book on patina, but have not yet played with
it again. I won’t until I get some shot cleaner and a new wire brush
(wore out the first one.)

Susan
Sun Country Gems LLC
http://www.suncountrygems.com


#3

I’d be interested in this, too. I read about it in Jinks McGrath’s
book on surface treatments and tried a couple she described.

I scrubbed the metal quite a while with bon ami and a 3m scrubee in
water. However, my patinating copper and brass with either a combo
of ammonia and vinegar in tobacco leaves with the metal placed in it
few a day or two, and with sprinkling salt and vinegar on the metal
and placing in an airtight container with ammonia sitting in a cup
inside to fume it, have been pretty hit-or-miss.

The blue color has tended to flake off (particularly when trying to
get the tobacco off the metal), and since patinas are supposed to be
in the surface of the metal, something isn’t right in my approach.

But it’s interesting, kind of fun, and the colors are indeed pretty.

Bill Mack


#4
and since patinas are supposed to be in the surface of the metal,
something isn't right in my approach. 

Bill, Patinas are not IN the surface of the metal. They are ON it.
Hopefully, though, they adhere well enough to stay there. But they
ARE a surface layer, not the outer surface of something inherently
imbedded into the metal surface. With those nice blue/greens,
getting it too thick is often a problem. Even Liver of sulphur black
patina on silver or copper based metals will flake off if you get it
too thick, going on too fast… And many of those decorative colored
patinas are fragile, needing overcoats of lacquer or some other
protectant, to become reasonably durable in use.

Peter Rowe


#5

Bill

I have just reheated a piece with a funky patina, and then pickled
and that worked. You could try that.

Dave Leininger


#6

Whenever I patinate a piece of bronze or copper I don’t recall ever
having placed the object in the patina solution. After the object is
quite clean (acid wash will usually do), I pour an aliquot of the
patination mixture in to a small container and use a brush to paint
the chemical on the object. This has several advantages. The first is
that you can observe the reaction with the metal and stop it when it
is dark enough. The second is that if a portion of the object doesn’t
develop enough color, you can place more of the chemical on that
spot. Usually you can continue the reaction at that particular spot.
It doesn’t hurt that the rest of the object dries while you do this.
A final point is that some patination formulas are expensive or
difficult to get. When you put a piece of metal in the soup,
chemical reactions occur which leave precipitates in the solution.
Usually the solution will still work but I prefer to leave my stock
solutions uncontaminated and fresh for each new use. I also like to
patinate different portions of an object with different solutions. On
section may be red/orange with others being being black, blue, green
or whatever I choose (or cause by accident. I do see unexpected
colors from time to time.) It is possible to clean a portion of an
object of oil or grease with solvent and to use the brush to match it
with the rest. I enjoy this process.

Gerald Vaughan


#7

Hi Gerald, I found your post interesting and it made me wonder about
a couple of things.Do you have any insight on masking off areas when
using multiple/different patinas on one piece? I have often get
bleeding or unsuccessful results, so I’m curious what you use.

My second question is when you paint on the patina, don’t you get
uneven tone, even double lap lines when a second dab of solution is
added? Do you use a big brush in relation to the size of the piece? I
paint on as you describe, as well as dip (LOS), so would love to know
any tips you have.

Lastly to the original poster, regarding blue patina on copper and
brass my favorite is Copper Nitrate (bright blue crystals are mixed
with water) this is applied while gently warming the piece with a
torch and dabbing the piece with a moderately loaded brush, it takes
a bit of practice, but you can reapply in areas until you get it
right w/o stripping. The solutions kind of sizzles and dries right
away, however, linger too long and it will burn the color and you
will need to redo that area. Practice and you will get the feel. Then
a coat or 2 of wax with help protect the patina. The wax darkens it a
bit. It would solve the problem that you are having with partial
coverage or 2 heavy in areas. I believe this process results in a
more permanent blue patina. Others may have different experiences,
granted most patinas have a limited life.

Kay Cummins
Out And About Girls


#8

Hello, Kay----You mentioned difficulties with “painting” a workpiece
with different patina materials to get a variety of colors. You are
correct. In a fashion it reminds me of watercolor painting where the
colors tend to blend or smear. Use the lightest colors first, wash
and dry the metal and go on to the next material. Most of the pieces
upon which I use multiple colors are relatively large. First, I let
gravity help in that I hold the piece in such a way that the part I
am coloring is at the lowest point so that fluid tends to drip off
rather than affect another part of the piece. I also point out that
the color can be selectively removed by application of acid with a
fine brush followed by a quick rinse. I also use abrasives to clean a
spot with which I am not happy and reapply the fluid. One should be
sure that the two or more chemical mixtures you are using are
compatible.

Applying acidic mixtures next to alkaline mixes can make a mess. It
helps in most cases to warm the piece before and even during
application so that the fluids react more quickly and dry faster. One
problem that I have is my impatience. I often find it difficult to
wait long enough for color to fully develop.

I truly find no problem with shadowy edges resulting from multiple
applications in problem areas. These can be usually be hidden, if
you wish, by “blending” using a small brush or piece of cloth.
Perhaps the reason I like to do things this way is that I rather
like some of the serendipitous designs that evolve. I find it easy
to use green against black, or blue with green. Orange/red can be
more difficult to achieve next to other colors. One can mask areas
with wax or shellac but I seldom bother (you must remove the mask to
proceed–organic solvents work best but come with their own setof
problems.).

Our patination processes are made to imitate the natural processes
that occur when brass, copper and bronze age in the corrosive air
and water of our planet (even more corrosive in recent centuries).
One color will quite naturally mutate/change to another in time. Wax
coatings can retard change but not stop it. Clear polymers or
plastics will last longer and be more protective. However, things
will change. I have found that bronzes I worked hard to patinate 40
or so years ago are different but better in that colors have blended
to richer and deeper tones. I always wonder how they will end up.
There are those and I am not sure that they are wrong, who advocate
using paint and pigments to color metals. There are strong
historical precedents for this technique.

I feel that I have not done the best job of explaining myself in
this note because it is largely experience and intuition that guide
me in this process, a difficult thing to explain. I did not bother
with recipes for colors since you obviously are familiar with them.
There are lots of recipes on the net and on Ganoksin.

Good luck—Gerald Vaughan


#9

Gerald Vaughan - Thanks for the patina response

Gerald, I completely understand your explanation. Thank you so much
for the detail. I don’t know why your response didn’t come through on
the daily digest.but I found it. My apologies to the rest of the
group, I would have responded directly to Gerald, but couldn’t figure
out how when I was in the archives!

Kay Cummins
Out And About Girls