[Regia-NA] copper for cooking

[rmhowe]

santell juan wrote:
> Copper is fine for cooking as long as you know the
> kind of solder that was used in assembly. Many
> overseas producers of cheap copper implements
> sometimes use solder with lead which is a definite no
> no if you wish to stay healthy. One way to use the
> piece if you really like it is to heat it up with a
> torch, remove the old solder completely and re-solder
> with a safe kind readily available at the hardware
> store.
>                 juan Santell

They also have a tendency to coat the interiors with
tin to prevent the copper from dissolving and tainting
the food. This is the silver stuff you see. It is applied
by coating the thoroughly scrubbed inside with sal ammoniac
and then ladling in melted tin while the container is
heated over tin's melting point over a fire, the stuff is
jiggled about and it covers the interior, then is poured
back into the container of melted tin.

Pure Lead has a higher melting point than many of the solders
that replaced it as I recall. If it were me I think I
would just have it -brazed- or silver soldered. I would
try to stay upwind of any lead fumes. You could always
overheat it and let it burn off. If it has zinc or lead
in the metal then it will boil out of the pores.
Expect the copper to be very malleable afterwards.

How do I know? I've collected oriental coins for very
many years. One time I got in a really badly corroded
box of them and cleaning the stuff with a pin pointed
tool to identify them was a real pain. So I asked a
chemistry professor who was also in our coin club how
to clean them. Heat them red-hot and drop them into
alcohol. You can see the zinc and lead sweat out and
gas. Left the coins an unnatural red copper color though
so I didn't do it to too many.

I've also made a few copper bowls long ago by beating.

As an example the Japanese Barkufu (tent government)
produced a document that discussed how many metalworkers
that smelted silver with a lead process were going to die
off each time they devalued the silver by remixing it
with a higher percentage of copper. Not that they cared
about the lower classes (they didn't) but skilled
workers dying off in large amounts were hard to replace.

To hide the increased copper content they leached the
surface of copper content by soaking the money (usually
stamped silver bars) with plum vinegar that restored
the silvery look.

As usual, bad money drives out good and everyone soon
hoarded the good stuff. No one wants to trade with the
new stuff.

Lead fumes definitely are a governmental no-no and
are liable to turn one into an idiot a bit faster
than alzheimers. It's really doubtful though that doing
it upwind in an outside workspace is gonna get you.

Magnus, who has collected such stuff over thirty some
years.