Subject: silly theoretical Brass question

From: [email-masked] (David Adams)
Date: 17 Jan 95 15:24:48 CST

According to an online table of the elements
zink boils about 1664 deg. F and copper doesn't
melt until abt 1982 deg. F, so how in heck do
they manage to mix the two to make brass???

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	-David  [email-masked]

-- 
	-David  [email-masked]

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From: [email-masked] (Daryl Bender)
Date: Wed, 18 Jan 1995 17:00:02 -0500

> 	-David  [email-masked]

My guess is they heat copper to 1982+ deg F add in zinc in the correct
proprtion, stir until mixed (trying not to breath the fumes) then cool and
serve. It will likely solidify at a third temperature. As you mix two
metals in different proportions the melt (solidify) temperature changes
with the proportions. Usually at some point there is a minimum (eutectic
point). 

Daryl 
-- 
Working, but not speaking for BNR.

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From: Alberic6 <[email-masked]>
Date: Mon, 23 Jan 95 00:09:34 -0500

Mike Schechter <[email-masked]> writes:
 
>In article <[email-masked]> Daryl Bender, [email-masked] writes:
 
Greetings:
 
The general advice I was given when I was learning to be a jeweler was
that yo always melt the hottest component, and then work your way down.
(for example, to make sterling silver, you melt the fine silver, then add
the copper.)  If you add the alloying agent first, you run the risk of
having the hotter one not go into solution completely and then it never
will, because the temprature you'd have to get the melt up to would be bad
for the rest of the batch.  (In open air, with sterling, anyway.)
 
The advice I remember for making brass is to add 33% (or so?) more zinc than
you really need, and also to float charcole dust on the surface of the melt.
The charcole will help keep the zinc from burning out completely, but it
still burns out enough that you apparently need to add a lot more than you
really think you need.  Having once mistakenly tried to cast brass without
doing this, I can say that the zinc comes out of solution almost explosively
in small enough batches.  (How did I discover that what I'd been told was
bronze was in fact brass?  When it started spitting chunks at me!)
(Never trust a smiling supplier!)
 
Later-
Alberic