Subject: Re: "pot metal" - what (exactly) is it?

From: [email-masked] (john O. Kopf)
Date: 22 Jan 1995 21:22:48 GMT

In article <[email-masked]>
[email-masked] (Robert Ryan) writes:
> There was a thread for a while regarding uses, properties, etc. of pot 
> metal, and an indication that pot metal is a zinc alloy, but I would 
> like to know as exactly as possible what "pot metal" is. I don't know if 
> there is a precise definition, or just an understanding of general 
> meaning.

A book I highly recommend is:

Turning and Mechanical Manipulation; Volume I:
Materials, Their Choice, Preperation and Various Modes of Working Them
By Holtzapffel
(published in 1843, reprinted by Astragal Press, available from
Lindsey)
It covers all of the craft materials (wood, bone, ivory, metals &
alloys,
etc. in common use 150 years ago.

About POT-METAL, he says:

"Again, the same proportions, namely two parts of copper, and one of
lead,
make a common inferior metal, called POT-METAL, or cock-metal, from its
employment in those respective articles.  This alloy is much softer
than brass, and hardly posssessses malleability; when for example, the
beer-tap is
driven into the cask, immediately after being scalded, the blow
occasionally
breaks it in pieces, from its reduced cohesion."

JK

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From: [email-masked] (David Adams)
Date: 23 Jan 95 17:04:26 CST

Pot metal usually refers to a zinc alloy.  Different alloys
might go by this name.  Zamak is a common one.  

I get the following from a nice periodic table of the elements
maintained at Los Alamos National Laboratory
found on the web at http://www-c8.lang.gov/periodic-main.html

Click on the table entry for Zn:

	". . . Large quantities of zinc are used to produce 
	die castings, used extensively by the automotive,
	electrical, and hardware industries.  An alloy
	called Prestal (R), consisting of 78% zinc and 
	22% aluminum is reported to be almost as strong
	as steel but as easy to mold as plastic.  It is
	said to be so plastic that it can be molded into
	form by relatively inexpensive die casts made 
	of ceramics and cement.  It exhibits superplasticity. . ."

-- 
	-David  [email-masked]

---

From: [email-masked] (Barry Workman)
Date: Wed, 25 Jan 1995 07:12:16 GMT

>Thanks

>Rob Ryan

Pot metal is any metal mixture that can be melted without the aid of
a foundry furnace.  After many long and exhausting hours of trying to
find a "real" definition this is the only conclusion that fits.  
Plumbers call any lead or lead alloy mix pot metal.  Many hardware
stores that claim to have "pot metal" acutally have plumbers lead.
Trophy shops call the zinc/lead alloy they use pot metal.  Elsewhere
I have read reference to babbet as being pot metal.  When all is said
and done, the only common ground that the different metals share is
a melting temp around 800F or lower.  This temprature is easy to get
on a plumbers stove or similar device.  Good kitchen stoves will also
produce temps that will melt most pot metals.  So it's anything that's
in the pot and melts.
-- 
    - Barry Workman