Hmty Km, the original black copper alloy

2017-05-02 14.51.03In working on our MMA reconstruction piece, I’ve been researching ancient bronze to better understand the composition of the tools we will be making. There is very little information out there on Etruscan era tools, and according to other who have studied this the tools were either melted down or corroded beyond recognition. I contacted two experts in ancient metallurgy from Academia.edu (a treasure trove of free information that I turn to often) and Dr Alessandra R G Giumlia-Mair has some helpful analysis she is willing to share. I find scientists to be incredibly helpful and willing to share information. It’s a great example to emulate in projects like this.

In reading some of her research papers, I came across the topic of Hmty Km (pronounced “hempty kem”) an Egyptian black copper alloy that is the predecessor of Shakudo in Japan, wu tong in China and was called Corinthian copper in the West. Apparently its use died out in the western world after it traveled to asia. This is the reason it is considered a Japanese technique today, its Egyptian and western beginnings being largely forgotten. It is primarily copper with small amounts of precious metals like gold and/or silver. Even percentages as small as 1 or 2 % gold greatly alter the patinas you can achieve. Of course, I was intrigued and had to whip some up right away. There are many, many recipes to choose from so I started with a few straightforward ones. An important element in many of the original alloys  is arsenical copper, or copper ore with arsenic in it, as it occurs in nature. Yikes! From my research so far, it seems the arsenic makes a harder alloy. Unless or until I can figure out a way to use the arsenic safely (which is doubtful) I will make do with a softer arsenic-free alloy. It remains unclear to me what effect, if any, the arsenic has on the patina of the finished piece but I might not be able to test that for safety reasons. It’s all fun and games in the studio until you give yourself arsenic poisoning….

The recipes I made are 94% Copper 6% Gold, 93% Copper 6% Gold 1% Silver and 70% Copper and 30% gold. We will see how they turn out when patinated but the shades are very lovely as is. Of course, if I wanted to keep them this shade they would have to be waxed or lacquered to seal in the color and keep them from oxidizing.6% Au 94% Cu alloy

left 6% right 30% AuLeft 94% Copper 6% gold, right 70% Copper 30% gold

 

 

 

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Construction details in Etruscan discs

Untitled-2Hi all,

Take a look at another one of the detail shots! From this view we can see two things clearly about their construction.

First, as indicated by the two arrows, you can easily see the seam between the thinner top layer and thicker back sheet.

Granulation works best on thin sheets (we usually use around 30 gauge) so we usually work on thin sheets and then solder them to a thicker

(sometimes lower karat) back sheet for strength; just as this ancient goldsmith has done.

Secondly, as indicated by the red rectangle, you can see the outer edge is not granulation but beaded wire. Beaded wire is an ancient technique

we haven’t practiced. It involves making relatively short lengths of wire (there will be more about how the ancient goldsmiths made wire in future posts)

and then using a tool to score horizontal indents along the length of the wire. This tool, along with the wire, was handmade and I feel like you can see how the same

toolmarks are repeated on each “bead”. You can also see how there is a typical looking fused connection between each bead and the backsheet.

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Check out the peg underneath one of the granulated discs

Untitled8aThis is a closeup of one of the concave granulated discs. At this level of magnification, you can easily see the peg it is resting on. This peg goes through the backsheet and is covered up by a small dome on the back. Also notice how easily you can see the seam in the wire circling the dome. Some slight damage to the back pushed this particular peg up a bit, making it a little higher and easier to see than the others. Although pristine ancient pieces are beautiful to look at, damage often reveals construction details that are difficult or impossible to see otherwise. Hurray for damage!

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The back of the earring from the MMA

14b14aHere is a back view of the disc earrings from the MMA. Seeing the backs of things is so instructive. For example, you can see that the concave granulated discs on the front are attached to the back with pegs then covered up with the small domes you see here. The center flower is attached the same way with the center dome. The backsheet of the center section is probably separate as well. For those of you who granulate, it’s easy to see the rational here. I use the same concept when making elaborately granulated pieces. It’s much easier and safer to granulate smaller parts and then assemble them using solder than to attempt a lot of granulation on one large piece.

The only evidence I see of any method of attachment for wearing these earrings is the two holes in the edges of the center circle. Presumably the ear wire was a separate piece. (?)

I’ll try to find another similar apparatus in some other  ancient examples.

Till next time!

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Lecture and Book Signing at Jewelry Arts by Author Anna Tabakhova

“Clasps, 4000 years of fasteners in jewellery” a story told for the very first time

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The author Anna Tabakhova, coming from Paris, will give a lecture on Clasps history and will sign her book.

Thursday June 8th 7:00pm

at Jewelry Arts Inc studio

22 East 49th street fourth floor NY NY 10017

At the crossroads of art book, historical research and technical manual, a book designed as a jewellery walk through time and space. From the Early Bronze Age to Fine Jewellery, 4,700 years surveyed, 32 historians consulted, 22 museums involved; 76 contributors, jewellers, artists and designers from 30 countries. Four millennia of inventiveness in jewellery are unveiled and illustrated with unpublished photographs; the operation of an ancient Egyptian clasp and the origin of the box clasp are finally revealed.

A book of 288 pages, 356 color photos, completed with a glossary of 28 original illustrations.

Anna Tabakhova is a jeweller-designer, born and working in Paris. Her approach is both that of a jeweller at her bench and that of a collector who likes to share her discoveries. She carried out her research starting from her own jewel collection – focused on interchangeable clasps – and documented this history of clasps through museums and private collections, meeting jewellers and designers from all over the world to make this book possible. She has exhibited at the Grand Palais in Paris a clasp that she designed and developed, inspired by the jewellery worn by Egyptian Princess Sat-Hathor-Yunet nearly 4,000 years ago.

The National gallery of Art in Washington said :

It is truly spectacular: rigorously academic on the one hand, and stunningly beautiful and entertaining on the other. Very, very well done.

The Victoria and Albert Museum in London said : Beautifully produced, and very carefully structured. You have done both makers and historians a huge service. The glossary will be extraordinarily useful. It’s a triumph.

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Progress on new project with The MMA

Untitled10bI was lucky enough to be granted access to photograph these glorious disc earrings last week and here is the first of the detail shots.

I’m obsessed with details and I’ve been fangirling over these shots all week. Mike and I will use these photos to riddle out what methods and tools were used.

We are also waiting for some micrographs (microscopic pictures) and other tests ordered by the MMA to truly reveal the secrets behind all the connections in the piece and the exact alloy.

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Exciting new project with The Met

We are embarking on an exciting new project with the help of the Metropolitan Museum of Art! Michael Ellis and I are attempting a recreation of these Etruscan beauties (earrings)using only ancient methods and tools. It should be a fascinating project and we hope to learn a lot. I’ll keep you all posted.2017-03-16 14.39.30-1

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Is Your Pickle Contaminated?

Does this ever happen in your studio?

You (or someone else) unthinkingly plunges your (ferrous metal) tweezers in the pickle? Or, someone absentmindedly puts something in the pickle pot with (ferrous metal) binding wire on it. Either way, everything in the pickle pot is now copperplated.

Does that mean your pickle is “contaminated” and must be changed?

No.

I have read in many sources and been told by many jewelers that once copperplating has happened in your pickle, it is “contaminated” and must be changed. The problem is, no one was ever able to answer my questions of what contaminated meant. Did it mean the pickle would no longer work? Could it damage my piece in some way? What negative effects could be expected? No one was ever able to answer any of my questions. That made me think it might be a myth, so I decided to test it out.

As it happens, my studio, Jewelry Arts Institute, does quite a bit of deliberate copperplating. One of the techniques we specialize in is 22k gold granulation. I’ll digress just a tiny bit for those who don’t know about how gold granulation is done. Granulation is accomplished by a technique called “colloidal soldering”. This means that the backsheet is heated and pickled a few times to raise a layer of pure gold to the surface. The granules or wires that are to be fused down are given a coat of copper in some way. This has a variety of possibilities, using powered copper carbonate, copper oxides, etc. The method we prefer as the neatest and most precise is copperplating in an acid bath. Copperplating in pickle works just as a basic battery does. Ferrous metal introduced into an acid solution creates an electrical charge. If the acid solution (the pickle we use is sodium bisulfate) has copper dissolved in it (as it will if you have been using it) the copper will be deposited on your metal. I was taught to take a small amount of used pickle, do my copperplating, and then discard the pickle.

I started testing in my home studio, copperplating in my main pickle and not changing the pickle afterward.

What happened?

Nothing.

The copperplating stopped just as soon as I removed my tweezers or binding wire. My pickle then performed as it always had. It lasted for a few months, depending on how heavily it was used, just as it had before. It cleaned off oxidation in a few minutes, quicker when warm, just as it did before. I have never yet been able to discern any difference between how pickle acts if copperplating has or has not occurred. Once I was sure of my results, we started doing the same thing in the school pickle and the pickle acts as it always has.

So, stop wasting your time and money and just change your pickle when it needs to be changed!

For more useful tips and insights into how things REALLY work in the studio please take a look at my new book, Soldering Demystified, available on Amazon.com.

 

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Is your Third Hand Ruining Your Soldering?

For some of you, the answer is yes! Here’s why:

Third hands (or arms) are made of steel which has a much higher melting point than the jewelry metals, silver, gold, brass, and copper. That’s a good thing or it wouldn’t be helpful in holding elements while we solder. However, third hands act as a heat sink meaning they can draw a lot of heat away from your piece and into themselves. Often, when solder refuses to flow properly it is because of the third arm drawing away too much heat from your soldering seam. You can use this feature to your advantage –for example, you can protect a previously soldered seam from reflow by clamping the third arm over it – but you need to know how to position the third arm properly when you do need your solder to flow unimpeded. The key concept is to position the third hand as far away as possible from your soldering seam. Here are a few examples:

RIGHT

finalrightdome

 

 

 

 

 

 

 

 

 

WRONG

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RIGHT

rightthird-arm-for-ring

 

 

 

 

 

 

 

 

 

WRONG

wrongthird-arn-for-ring

 

 

 

 

 

 

 

 

That’s all there is to it! So, be mindful of where you place your third hand and it will never again ruin your solder flow.

To learn more about how to always solder successfully, please take a look at my book Soldering Demystified.

You can also join me this August for Soldering Demystified Boot Camp.

Happy Soldering!

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The Best Jewelry Soldering Tip Ever

How many times have you soldered on a finding youalignment2
thought was perfectly lined up with the rest of your piece,
only to find it is several degrees off center? (And why
does this become so easily visible only after you have
soldered it on?!!!) Aligning elements for soldering is one of
the biggest obstacles confronted by students and
professionals alike, and yet the problem has a really easy
solution. In fact, when this idea finally occurred to me about
ten years ago, my first thought was, “what took me so
long?”! When I made a video about it for the Jewelry Arts
Institute’s YouTube channel, I called it The Best Jewelry
Soldering Tip Ever, and I still believe that to be true.
For more helpful tips and information about soldering,
check out my new soldering book, Soldering Demystified available on Amazon.com.

1 Get a new Solderite board and line up the
end of a metal ruler with the edge of your
board. Draw the line using a ballpoint pen
(the X axis).
Note: Ballpoint pens write best on this surface.

alignment8aa

 

 

 

 

 

 

 

 

2 Line up the edge of your ruler with the
bottom edge of your block, at 90° to the
first line, and draw this line with your pen
(the Y axis).

alignment9aa

 

 

 

 

 

 

 

 

3 For more complicated setups, use an angle
ruler to draw in 4 more lines at 45 degree
angles to your first lines. (Your lines will fade
with use, so freshen them up occasionally.)

That’s all there is to it and this technique will help

with lots of different kinds of set-ups.

Happy Soldering!

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