Re: Copper Casting In America (Trevelyan)

From: Gary Coffman (ke4zv_at_bellsouth.net)
Date: 07/03/04 

Date: Sat, 03 Jul 2004 04:54:31 -0400

On Thu, 01 Jul 2004 12:26:31 GMT, Seppo Renfors <Renfors@not.com.au> wrote:
>Gary Coffman wrote:
>>
>> On Wed, 30 Jun 2004 14:53:00 -0400, Yuri Kuchinsky <yuku@trends.ca> wrote:
>> >Gary Coffman wrote:
>> >
>> >[snip]
>> >
>> >> The apparent fact that the Native Americans *didn't* cast native
>> >> copper
>> >
>> >This is a "fact" only if you disregard all evidence to the
>> >contrary, as you appear to be doing.
>>
>> Virtually all of the evidence presented to date in this thread is
>> against casting of ancient Michigan native copper artifacts. If
>> you have conclusive evidence showing characteristic porosity
>> in all the items claimed to be cast, if you have evidence showing
>> a chemical analysis of true alloying between the native copper
>> and other metals (mainly silver) found with it in the halfbreed
>> ore matrix, if you have evidence of large numbers of identically
>> dimensioned artifacts representative of a casting provenance,
>> etc, then present it. Otherwise you have no case.
>
>You cannot claim "you have no case" UNLESS you prove there is no "true
>alloying between the native copper and other metals" and that takes an
>analysis of the metals in the artefacts found. It works both ways you
>know.

Actually, I can make the claim, because heavily alloyed copper is no longer
native copper.

>> What we do know is that ancient Michigan artifacts have been
>> found with silver inclusions. That precludes the possibility that
>> they were ever melted.
>
>No, it precludes that item from having been melted only. You cannot
>extrapolate that beyond the artefact itself.

It is a conclusive indication for any case where silver inclusions are
found.

>> We do know that of the artifacts which
>> have been put forward as evidence of copper casting, all but
>> one do *not* show the characteristic porosity of atmospheric
>> melting of copper, and that one does not appear to be a deliberate
>> casting.
>
>We see TWO artefacts being claimed as being cast - one being conceded
>as being cast. We don't know the composition of the metal of the
>second artefact to be able to discard it as "not cast".

Neither Tom or I have conceded R666 was cast. We've agreed it shows
all the characteristic signs of atmospheric melting, but it doesn't automatically
follow that it was deliberately cast.

>You have claimed it is the sign of "copper" being overheated - ie to
>melting point else bubbles cannot form. At the same time you have also
>stated the heat source has to be forced air type to get it hot enough
>to melt copper.

Copper does not need to be heated to melting for blisters to form.
Please go back and reread Neubauer for examples of native copper
which blistered on annealing *without* being raised to melting
temperature. You can blow bubbles in bubble gum without melting it,
you can do the same in copper. It merely has to reach a sufficient
state of plasticity for the gas pressure from inclusions to deform it
into a blister.

>I see those two statements as being inconsistent with each other. If
>the Copper was simply hammered and annealed, the temp should NOT be
>able to get high enough to cause any bubbling.

Well, then you're wrong.

Gary

Relevant Pages

  • Re: Copper Casting In America (Trevelyan)
    ... >>Those pictures do not show any evidence of the characteristic ... >>porosity copper casting would produce. ...
    (sci.archaeology)
  • Re: Copper Casting In America (Trevelyan)
    ... > Virtually all of the evidence presented to date in this thread is ... > against casting of ancient Michigan native copper artifacts. ... We see TWO artefacts being claimed as being cast - one being conceded ...
    (sci.archaeology)
  • Re: Copper Casting In America (Trevelyan)
    ... > Virtually all of the evidence presented to date in this thread is ... > against casting of ancient Michigan native copper artifacts. ... We see TWO artefacts being claimed as being cast - one being conceded ...
    (sci.anthropology)
  • Re: Copper Casting In America (Trevelyan)
    ... >> Virtually all of the evidence presented to date in this thread is ... >> against casting of ancient Michigan native copper artifacts. ...
    (sci.anthropology)
  • Re: Copper Casting In America (Trevelyan)
    ... Virtually all of the evidence presented to date in this thread is ... against casting of ancient Michigan native copper artifacts. ...
    (sci.anthropology)