Producing verdegris using malachite and azurite

Hi Lois,

Impressed with your persistence! I’m also interested in whether this
would work well to join sheets or sheet and wire. I took a look at
the wikipedia article on “Verdegris.” It states:

“Verdigris is a variable chemical mixture of compounds, complexes and
water. The primary components are copper salts of acetate, carbonate,
chloride, formate, hydroxide and sulfate. The secondary components
are other metallic salts, acids (organic and mineral), atmospheric
gases and water. All the components are in an ever-changing and
extremely sophisticated electrochemical reaction equilibrium that is
dependent on the ambient environment.”

So, like most common reactions, it produces a witches brew of stuff.
The exact composition of one batch of verdegris is probably not
reproducible and probably doesn’t matter that much for most
applications, but who knows for sure? The article also details old
methods of making verdegris, evidently for paint pigments.

An 18th cent. method involved putting copper plates into clay pots
filled with “distilled wine,” which would have been high alcohol
wine, 30-65% alcohol. There would have been iron in the clay pots,
possibly leached out by the alcohol, so I wouldn’t worry too much
about the purity of the reaction.

I think you could try immersing copper strips in vinegar (5% acetic
acid) or get some glacial acetic and dilute it to 15% [always add
acid to water, not the other way round]. Or try immersing the copper
in some high alcohol solution.

You can get various forms of denatured alcohol or use vodka or
brandy, which is actually distilled wine. You can warm the solution
to get a faster reaction or even file the copper to get copper

Since there are lots of compounds here, as per the Wiki quote, I
would put this somewhere outside, such as on a sheltered porch,
while it works and would solder with good ventilation, as there may
be small amounts of some stuff you don’t want to breath a lot of. The
chemical used to denature the alcohol would also be an issue, but
probably not a major one. You’d just have to look at all the MSDS’s
for all the compounds and make a reasonable decision. Since the main
component of the verdegris seems to be copper acetate and since you
would use small amounts of the verdegris and use some ventilation
when using it, your exposure to anything would be small. Certainly
there are various copper and other metallic salts, formates, etc.
all around us.

Although most of this stuff is something you could find in an
ordinary kitchen, use common sense and eye protection as needed.

If you go further with this is would be interesting to hear of your

One can simply use deep blue used pickle as well! Most of us keep
some around just for granulation purposes. I mix it with a bit of
tragacanth gum (powdered) and a pinch of crystalline borax (if a
silver is the metal being attached in a granular form). If I am
working with high karat gold and the granules are tiny I add gum to
the ‘used pickle’,If they are large and/or high karat gold to high
karat gold they need almost nothing more than the clear deep blue
copper saturated pickle. the gums that can be used add the sticking
power. I have used diluted metal clay slip mixed with deep blue
pickle too - with excellent results.

It is always a good idea when you have saturated pickle to keep a
bit in a sealed container out of the sunlight. If you choose a glass
jar, make sure the metal lid is enamelled on the inside (it is
usually white save for the ring around the edge that contacts with
the edge of the jar) or the pickle will eat away the clear thin
coating on the cap and rust can contaminate the solution if it is
inadvertently shaken or accidentally knocked over.

When the pickle is no longer useful (it is also good for plating
things and has other uses as well) it should be neutralised with
sodium bicarbonate (baking soda) before disposal: pouring it into any
drainage system- particularly if the output flows into a stream or
septic system as it can harm beneficial bacteria that digest oils,
grease and solids.

Even diluted it can be toxic to aquatic life… rer

Here is some basic info on soldering with copper compounds.

James Binnion

How do jewelers dispose of spent pickle? It contains copper and
silver, which are both toxic to fish and plants. I work in a lab, and
we have standard procedures for disposing of toxic waste.

Dear James,

The saying, “when the student is ready the teacher appears”,
certainly applies to me. Thank you for bringing this to
my attention. Many months ago I did read it but my eyes glazed over
and very little penetrated. Today, I understood every word. How the
granulation process works is no longer amystery. Now to implement the
techniques. I do love challenges.

Kind regards,

Dear RER,

have used diluted metal clay slip mixed with deep blue pickle too -
with excellent results. 

Great The blue pickle with a little glue to hold the
high karatconnection is an excellent tip. Will try your suggestion.
The gum tragacanth has arrived so I am all set to start

What is metal clay slip?

Kind regards,

Hi Karen,

The recycling center in my town has S. T.O. P. (Stop Throwing Out
Pollutants) Day available to residents twice a year. I throw some
baking soda in the spent pickle and store it until I can take it to
the dump.

Kind regards,

Hello Lois,

A brief summary: Metal clay is talcum powder fine metal "particles"
suspended in a binder and sold in lump form. Metal clays include:
fine silver, sterling silver, 22k gold, bronze, copper, steel. Metal
clays are formed, dried, and then fired in a kiln. The binder burns
away, the metal particles sinter (fuse), and after firing what
remains is solid metal.

Some of these also come in a more liquid form called Slip or Paste,
which is similar in use, though not material, to the Slip used by

It is possible to make one’s own Slip by adding a little distilled
water, in very small increments, to lump metal clay. Slip is used:
to join individual pieces of dried metal clay, before firing; to
make repairs to dried metal clay; etc.

For more about metal clay, check out

Hope this is useful,
Linda Kaye-Moses

P. S. I’m teaching my Chasing the Rainbow class at Snow Farm
beginning this Sunday, a class on metal clay and enameling,
partially supported by a grant from the Enamelist Society.

How do jewelers dispose of spent pickle? 

Add baking soda to neutralize and throw away as solid waste in the

Unless you have a hazardous waste drop off place in your town.


Sorry, the Link I had wanted to send re: metal clay was
somehow dropped from my message. Here is it again

Linda K-M