Dear Richard Furrer,
I just came back from Jordan, were a very interesting and fruitful archaeometallurgy and archaeology conference was held in Amman and Faynan. It was very nicely planned and organized by Dr. Bill  Finlayson, Head of C.B.R.L.
Opening the e-mail today, I was very glad to see the interest in my article on recasting the Nahal Mishmar Hoard. 
Now for your qwestions:
We choose the investment material after  examining (Rungwe Kingdon, his wife Claude and myself) the surfaces of the original objects in the Israel Museum and after analyzing (Peter Northover and myself) the metallography and the chemical composition of these objects. 
By combining the results we could identify from were and how the objects were cast and what was the original roughness of the investment material and that it was pressed to the wax surfaces and not painted on them (remains of sprues, unpolished surfaces, casting defects, remaining core material, etc.).
As for the mixture, we consult with Steve Hurst, an expert in traditional casting. According to the ethnological parallels of existing lost wax techniques in traditional societies, we had two major options: a coarser investment material of clay (circa 50%) mixed with one stomach animal  dung (horse, in our experiment) like in Africa, or a finer material of clay mixed with more than one stomach animal (sheep, in our experiment).  As Peter Northover mentioned in his reply, we tried first to add also some chopped straw which was not needed with the wonderful properties of the Cu + Sb and As in running like water as melt and filling every part of the mould and duplicating in great details the inner surface of the investment. After presenting the experiment and submitting the article, we continue to experiment with finer investment material of clay mixed with sheep dung. Just recently  I analyzed some medieval Islamic cores and investments remains, showing the same use of animal dung mixed with the clay. 
For polishing, we tried mainly the effect of various stones (lime, Sand, etc.) on this hard material, as mentioned in the article. You are more than welcome to contact me directly and we could discuss in more details the grinding and polishing possibilities and maybe experimenting some more.
Let me use this opportunity to remind us all that field experiments like this could never prove how things were actually done in antiquity, the most we could do is to come as close as possible to some probable options of how those ancient metals could have been made. 

I hope this answer some of your questions (as well as Aaron Shugar interest in the subject),  Happy Passover,          Sariel. 

P.S. I would much appreciate if you could send me a Xerox copy of my article. The book + the offprint was probably sent by Andreas to the dept. in Oxford instead of Weizmann Inst. in Israel.  

>>> [log in to unmask] 04/19/00 01:10am >>>
Well,
Thilo Rehren was kind enough to arrange purchase of the book "The beginnings of
Metallurgy"  and in it was the paper by Dr. Shalev on the Nahal Mishmar hoard
find. I'm no archeologist and actually have very little advanced schooling, but
was curios as to the casting techniques and finish work after the casting.

The castings pictured in the paper seemed a bit rough and it reads like a
mixture of dung, grog and clay was used to coat the wax model. I have done some
"native" casting and I found it much better to use a fine clay mix. The finer
the clay slurry the better the transfer of detail and it would seem to me that
the ancients would have known this. A dip in the slurry seems to pick up more
detail then brushing it on. I have not seen any original casting molds and do
not know if the slurry layer immediately surrounding the wax (or whatever the
positive would have been) would survive the passage of time or what tests would
show composition.

Also I was wondering if the casting was cleaned with abrasives (grit in an
oiled cloth) or files or scrapped clean of casting residue.
My last question involved burnishing of the surface -- i.e. was abrasive used
to bring out a bright finish or was the artifact planished and burnished?

I have no idea how much can be known, how much was recorded or how much
reproduction knowledge has been accumulated. I do know that I am very pleased
that such experimental investigations are being done. Someday I would like to
take part in them.

Richard Furrer
Sturgeon Bay, Wisconsin
USA

Aaron Shugar wrote:

> Richard,
>
> I would hope that I am not the only one that would also be interested in
> the questions you have about the re-casting of the Nahal Mishmar metal
> objects.
>
> would you mind posing your questions to the group?
>
> Aaron Shugar
> Institute of Archaeology
> University College London
> London, WC1H 0PY
>
> At 11:13 AM 4/18/00 -0400, you wrote:
> >Hello all,
> >I have just read Sariel Shalev's article on recasting the Nahal Mishmar
> hoard finds
> >and have a few questions. Is Sariel on the list or could someone aid me in
> more
> >personal communications?
> >
> >Richard Furrer
> >
> >
> >





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