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Gary Coffman
 
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Default Copper Casting In America (Trevelyan)

On Mon, 28 Jun 2004 09:04:49 +1200, Eric Stevens wrote:
On Sun, 27 Jun 2004 03:03:50 -0400, Gary Coffman
wrote:
On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald wrote:
Eric Stevens wrote:
On Fri, 11 Jun 2004 22:57:04 GMT, (Gary Coffman)
wrote:
But that said, casting pure copper is a bitch.


This from the guy who has just written that the task can be undertaken
by low-skilled workers?

Eric, I read that to mean that casting, in general (as with
iron, silver, bronze, gold, etc.) can be done by folks with
fewer skills than smiths. However, copper appears to present
particular problems with casting that are not so pronounced with
other metals, and which require higher skill levels than would
be required by those who cast other metals.


Exactly, and further, skill alone isn't sufficient to make sound
castings of pure copper. The proper equipment is also required.
Specifically, an inert atmosphere furnace. That technology
didn't exist until the late 19th century.


Just as well the ancient egyptians didn't know that they couldn't do
what they were doing. :-)


So, are you claiming to have evidence that the ancient Egyptians
successfully cast pure native copper?

The metallurgical references I have say that native copper was
extremely rare in Egypt. Almost all of the copper they had was
refined from ores (smelted), and the results were *not* pure
copper. Rather, they were alloys, whether intentional or not,
of copper, arsenic, zinc, iron, or tin. These alloys behave *very*
differently from pure native copper when casting is attempted.

Gary